International Severe Acute Respiratory And Emerging Infections Consortium Research Articles

Changes in hospital mortality in patients with cancer during the COVID-19 pandemic (ISARIC-CCP-UK): a prospective, multicentre cohort study

Patients with cancer are at greater risk of dying from COVID-19 than many other patient groups. However, how this risk evolved during the pandemic remains unclear. We aimed to determine, on the basis of the UK national pandemic protocol, how factors influencing hospital mortality from COVID-19 could differentially affect patients undergoing cancer treatment. We also examined changes in hospital mortality and escalation of care in patients on cancer treatment during the first 2 years of the COVID-19 pandemic in the UK. We conducted a prospective cohort study of patients aged older than 19 years and admitted to 306 health-care facilities in the UK with confirmed SARS-CoV-2 infection, who were enrolled in the International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) WHO Clinical Characterisation Protocol (CCP) across the UK from April 23, 2020, to Feb 28, 2022; this analysis included all patients in the complete dataset when the study closed. The primary outcome was 30-day in-hospital mortality, comparing patients on cancer treatment and those without cancer. The study was approved by the South Central-Oxford C Research Ethics Committee in England (Ref: 13/SC/0149) and the Scotland A Research Ethics Committee (Ref 20/SS/0028), and is registered on the ISRCTN Registry (ISRCTN66726260). 177 871 eligible adult patients either with no history of cancer (n=171 303) or on cancer treatment (n=6568) were enrolled; 93 205 (52·4%) were male, 84 418 (47·5%) were female, and in 248 (13·9%) sex or gender details were not specified or data were missing. Patients were followed up for a median of 13 (IQR 6-21) days. Of the 6568 patients receiving cancer treatment, 2080 (31·7%) died at 30 days, compared with 30 901 (18·0%) of 171 303 patients without cancer. Patients aged younger than 50 years on cancer treatment had the highest age-adjusted relative risk (hazard ratio [HR] 5·2 [95% CI 4·0-6·6], p<0·0001; vs 50-69 years 2·4 [2·2-2·6], p<0·0001; 70-79 years 1·8 [1·6-2·0], p<0·0001; and >80 years 1·5 [1·3-1·6], p<0·0001) but a lower absolute risk (51 [6·7%] of 763 patients <50 years died compared with 459 [30·2%] of 1522 patients aged >80 years). In-hospital mortality decreased for all patients during the pandemic but was higher for patients on cancer treatment than for those without cancer throughout the study period. People with cancer have a higher risk of mortality from COVID-19 than those without cancer. Patients younger than 50 years with cancer treatment have the highest relative risk of death. Continued action is needed to mitigate the poor outcomes in patients with cancer, such as through optimising vaccination, long-acting passive immunisation, and early access to therapeutics. These findings underscore the importance of the ISARIC-WHO pandemic preparedness initiative. National Institute for Health Research and the Medical Research Council.

Symptomology following COVID-19 among adults in Alberta, Canada: an observational survey study

ObjectiveFatigue, headache, problems sleeping and numerous other symptoms have been reported to be associated with long COVID. However, many of these symptoms coincide with symptoms reported by the general population,...

Event rates and incidence of post-COVID-19 condition in hospitalised SARS-CoV-2 positive children and young people and controls across different pandemic waves: exposure-stratified prospective cohort study in Moscow (StopCOVID)

BackgroundLong-term health outcomes in children and young people (CYP) after COVID-19 infection are not well understood and studies with control groups exposed to other infections are lacking. This study aimed to investigate the incidence of post-COVID-19 condition (PCC) and incomplete recovery in CYP after hospital discharge and compare outcomes between different SARS-CoV-2 variants and non-SARS-CoV-2 infections.MethodsA prospective exposure-stratified cohort study of individuals under 18 years old in Moscow, Russia. Exposed cohorts were paediatric patients admitted with laboratory-confirmed COVID-19 infection between April 2 and December 11, 2020 (Wuhan variant cohort) and between January 12 and February 19, 2022 (Omicron variant cohort). CYP admitted with respiratory and intestinal infections, but negative lateral flow rapid diagnostic test and PCR-test results for SARS-CoV-2, between January 12 and February 19, 2022, served as unexposed reference cohort. Comparison between the ‘exposed cohorts’ and ‘reference cohort’ was conducted using 1:1 matching by age and sex. Follow-up data were collected via telephone interviews with parents, utilising the long COVID paediatric protocol and survey developed by the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC). The WHO case definition was used to categorise PCC.ResultsOf 2595 CYP with confirmed COVID-19, 1707 (65.7%) participated in follow-up interviews, with 1183/1707 (69%) included in the final ‘matched’ analysis. The median follow-up time post-discharge was 6.7 months. The incidence of PCC was significantly higher in the Wuhan variant cohort (89.7 cases per 1000 person-months, 95% CI 64.3–120.3) compared to post-infection sequalae in the reference cohort (12.2 cases per 1000 person-months, 95% CI 4.9–21.9), whereas the difference with the Omicron variant cohort and reference cohort was not significant. The Wuhan cohort had higher incidence rates of dermatological, fatigue, gastrointestinal, sensory, and sleep manifestations, as well as behavioural and emotional problems than the reference cohort. The only significant difference between Omicron variant cohort and reference cohort was decreased school attendance. When comparing the Wuhan and Omicron variant cohorts, higher incidence of PCC and event rates of fatigue, decreased physical activity, and deterioration of relationships was observed. The rate of incomplete recovery was also significantly higher in the Wuhan variant cohort than in both the reference and the Omicron variant cohorts.ConclusionsWuhan variant exhibited a propensity for inducing a broad spectrum of physical symptoms and emotional behavioural changes, suggesting a pronounced impact on long-term health outcomes. Conversely, the Omicron variant resulted in fewer post-infection effects no different from common seasonal viral illnesses. This may mean that the Omicron variant and subsequent variants might not lead to the same level of long-term health consequences as earlier variants.

Assessment of the state of children after COVID-19 and other acute respiratory infections using the ISARIC COVID-19 survey

Introduction. The state of children had suffered from COVID-19 causes various persistent symptoms affecting on patient well-being and quality of life which is a significant healthcare issue. &#x0D; The aim of the work. To assess health and well-being of children following COVID-19 and other acute respiratory infections. &#x0D; Materials and methods. This is a case-control study including children with history of PCR-confirmed COVID-19 (n = 261) and other acute respiratory infections (n = 198). Patients were assessed 6 months and 1 year after the infection using the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) COVID-19 questionnaire for children. The prevalence of symptoms including fatigue, weakness, lack of energy, as well as the emotional well-being, social relationships, and social activity of children was evaluated. &#x0D; Results. Children with history of COVID-19 in six months had significantly higher rates of weakness and decreased school attendance compared to children with other acute respiratory infections. 12 months after infection, children in the case group were significantly more likely to experience poor concentration, weakness, a decreased sense of belonging and school attendance. However, 12 months after infection, control group had significantly higher rates of fatigue. &#x0D; Conclusion. Children with a history of mild COVID-19 and other acute respiratory infections may experience ongoing health problems for 1 year after the infection, requiring greater attention from healthcare professionals and family members.

Implementation of Recommendations on the Use of Corticosteroids in Severe COVID-19

Research diversity and representativeness are paramount in building trust, generating valid biomedical knowledge, and possibly in implementing clinical guidelines. To compare variations over time and across World Health Organization (WHO) geographic regions of corticosteroid use for treatment of severe COVID-19; secondary objectives were to evaluate the association between the timing of publication of the RECOVERY (Randomised Evaluation of COVID-19 Therapy) trial (June 2020) and the WHO guidelines for corticosteroids (September 2020) and the temporal trends observed in corticosteroid use by region and to describe the geographic distribution of the recruitment in clinical trials that informed the WHO recommendation. This prospective cohort study of 434 851 patients was conducted between January 31, 2020, and September 2, 2022, in 63 countries worldwide. The data were collected under the auspices of the International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC)-WHO Clinical Characterisation Protocol for Severe Emerging Infections. Analyses were restricted to patients hospitalized for severe COVID-19 (a subset of the ISARIC data set). Corticosteroid use as reported to the ISARIC-WHO Clinical Characterisation Protocol for Severe Emerging Infections. Number and percentage of patients hospitalized with severe COVID-19 who received corticosteroids by time period and by WHO geographic region. Among 434 851 patients with confirmed severe or critical COVID-19 for whom receipt of corticosteroids could be ascertained (median [IQR] age, 61.0 [48.0-74.0] years; 53.0% male), 174 307 (40.1%) received corticosteroids during the study period. Of the participants in clinical trials that informed the guideline, 91.6% were recruited from the United Kingdom. In all regions, corticosteroid use for severe COVID-19 increased, but this increase corresponded to the timing of the RECOVERY trial (time-interruption coefficient 1.0 [95% CI, 0.9-1.2]) and WHO guideline (time-interruption coefficient 1.9 [95% CI, 1.7-2.0]) publications only in Europe. At the end of the study period, corticosteroid use for treatment of severe COVID-19 was highest in the Americas (5421 of 6095 [88.9%]; 95% CI, 87.7-90.2) and lowest in Africa (31 588 of 185 191 [17.1%]; 95% CI, 16.8-17.3). The results of this cohort study showed that implementation of the guidelines for use of corticosteroids in the treatment of severe COVID-19 varied geographically. Uptake of corticosteroid treatment was lower in regions with limited clinical trial involvement. Improving research diversity and representativeness may facilitate timely knowledge uptake and guideline implementation.

428. Risk Stratification and Clinical Outcomes in a Mixed Vaccination Cohort of COVID-19 Patients Admitted in a Tertiary Hospital Using ISARIC 4C Scores

Abstract Background The risk of clinical deterioration and death with the use of prognostic tools remain necessary for strategic planning among COVID-19 patients. The International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC) developed and validated Coronavirus Clinical Characterization Consortium (4C) scores to predict clinical deterioration and mortality. ISARIC 4C scores uses readily available clinical parameters. With the increasing uptake of COVID-19 vaccine, there is a need to evaluate these tools. The study examined a cohort of fully vaccinated (FV), partially vaccinated (PV) and unvaccinated (UV) COVID-19 patients and determined their clinical outcomes and stratified risks using ISARIC 4C scores. Methods We reviewed medical records of confirmed COVID-19 patients admitted to a single tertiary hospital between May 2021 and April 2022. Vaccination status were classified as FV, PV and UV. The primary outcome was in-hospital mortality. Baseline data were collected and predictors recorded upon admission were used to calculate the 4C scores. Multiple logistic regression analysis was used to determine the association of vaccination status and 4C Deterioration and Mortality scores with in-hospital mortality. STATA 14 was used for data analysis and p&amp;lt; 0.05 was considered statistically significant. Results A total of 301 confirmed COVID-19 patients were included and 46.5% were fully vaccinated. FV patients had significantly lower CRP (p&amp;lt; 0.0001), had higher mean oxygen saturation (p&amp;lt; 0.0001), had lower mean mortality score (p=0.004), had lower mean % risk for deterioration (p&amp;lt; 0.0001) and had significantly lower 30-day mortality (&amp;lt; 0.0001) compared to those UV and PV. Patient who died had significantly higher mean age (p=0.001), lower mean lymphocyte ratio (p=0.0004), had significantly higher mean deterioration and mortality score (p&amp;lt; 0.0001). Being fully vaccinated was associated with lower risk for mortality (OR=0.4, 95%CI=0.2 to 0.7). Conclusion Fully vaccinated patients were at lower risk for deterioration and mortality. High ISARIC 4C scores were also significantly associated with higher risk for mortality. Risk stratification tools should be utilized in COVID-19 management as they provide a helpful means to identify patients at risk for worse outcomes. Disclosures All Authors: No reported disclosures

Utility of the 4C ISARIC mortality score in hospitalized COVID-19 patients at a large tertiary Saudi Arabian center.

The International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC) 4C mortality score has been used before as a valuable tool for predicting mortality in COVID-19 patients. We aimed to address the utility of the 4C score in a well-defined Saudi population with COVID-19 admitted to a large tertiary referral hospital in Saudi Arabia. A retrospective study was conducted that included all adults COVID‑19 patients admitted to the Armed Forces Hospital Southern Region (AFHSR), between January 2021 and September 2022. The receiver operating characteristic (ROC) curve depicted the diagnostic performance of the 4C Score for mortality prediction. A total of 1,853 patients were enrolled. The ROC curve of the 4C score had an area under the curve of 0.73 (95% CI: 0.702-0.758), p<0.001. The sensitivity and specificity with scores >8 were 80% and 58%, respectively, the positive and negative predictive values were 28% and 93%, respectively. Three hundred and sixteen (17.1%), 638 (34.4%), 814 (43.9%), and 85 (4.6%) patients had low, intermediate, high, and very high values, respectively. There were significant differences between survivors and non-survivors with regard to all variables used in the calculation of the 4C score. Multivariable logistic regression analysis revealed that all components of the 4C score, except gender and O2 saturation, were independent significant predictors of mortality. Our data support previous international and Saudi studies that the 4C mortality score is a reliable tool with good sensitivity and specificity in the mortality prediction of COVID-19 patients. All components of the 4C score, except gender and O2 saturation, were independent significant predictors of mortality. Within the 4C score, odds ratios increased proportionately with an increase in the score value. Future multi-center prospective studies are warranted.

External validation of the ISARIC 4C Mortality Score to predict in-hospital mortality among patients with COVID-19 in a Canadian intensive care unit: a single-centre historical cohort study.

With uncertain prognostic utility of existing predictive scoring systems for COVID-19-related illness, the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) 4C Mortality Score was developed by the International Severe Acute Respiratory and Emerging Infection Consortium as a COVID-19 mortality prediction tool. We sought to externally validate this score among critically ill patients admitted to an intensive care unit (ICU) with COVID-19 and compare its discrimination characteristics to that of the Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores. We enrolled all consecutive patients admitted with COVID-19-associated respiratory failure between 5 March 2020 and 5 March 2022 to our university-affiliated and intensivist-staffed ICU (Jewish General Hospital, Montreal, QC, Canada). After data abstraction, our primary outcome of in-hospital mortality was evaluated with an objective of determining the discriminative properties of the ISARIC 4C Mortality Score, using the area under the curve of a logistic regression model. A total of 429 patients were included, 102 (23.8%) of whom died in hospital. The receiver operator curve of the ISARIC 4C Mortality Score had an area under the curve of 0.762 (95% confidence interval [CI], 0.717 to 0.811), whereas those of the SOFA and APACHE II scores were 0.705 (95% CI, 0.648 to 0.761) and 0.722 (95% CI, 0.667 to 0.777), respectively. The ISARIC 4C Mortality Score is a tool that had a good predictive performance for in-hospital mortality in a cohort of patients with COVID-19 admitted to an ICU for respiratory failure. Our results suggest a good external validity of the 4C score when applied to a more severely ill population.

Characteristics and outcomes of an international cohort of 600 000 hospitalized patients with COVID-19.

We describe demographic features, treatments and clinical outcomes in the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) COVID-19 cohort, one of the world's largest international, standardized data sets concerning hospitalized patients. The data set analysed includes COVID-19 patients hospitalized between January 2020 and January 2022 in 52 countries. We investigated how symptoms on admission, co-morbidities, risk factors and treatments varied by age, sex and other characteristics. We used Cox regression models to investigate associations between demographics, symptoms, co-morbidities and other factors with risk of death, admission to an intensive care unit (ICU) and invasive mechanical ventilation (IMV). Data were available for 689 572 patients with laboratory-confirmed (91.1%) or clinically diagnosed (8.9%) SARS-CoV-2 infection from 52 countries. Age [adjusted hazard ratio per 10 years 1.49 (95% CI 1.48, 1.49)] and male sex [1.23 (1.21, 1.24)] were associated with a higher risk of death. Rates of admission to an ICU and use of IMV increased with age up to age 60years then dropped. Symptoms, co-morbidities and treatments varied by age and had varied associations with clinical outcomes. The case-fatality ratio varied by country partly due to differences in the clinical characteristics of recruited patients and was on average 21.5%. Age was the strongest determinant of risk of death, with a ∼30-fold difference between the oldest and youngest groups; each of the co-morbidities included was associated with up to an almost 2-fold increase in risk. Smoking and obesity were also associated with a higher risk of death.The size of our international database and the standardized data collection method make this study a comprehensive international description of COVID-19 clinical features. Our findings may inform strategies that involve prioritization of patients hospitalized with COVID-19 who have a higher risk of death.

Relevance of prediction scores derived from the SARS-CoV-2 first wave, in the evolving UK COVID-19 second wave, for safe early discharge and mortality: a PREDICT COVID-19 UK prospective observational cohort study

ObjectiveProspectively validate prognostication scores, SOARS and 4C Mortality Score, derived from the COVID-19 first wave, for mortality and safe early discharge in the evolving pandemic with SARS-CoV-2 variants (B.1.1.7 replacing...

International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC). A new collaborative global platform for global clinical trials targeting post-COVID19 patients.

Background: In response to the pandemic caused by COVID-19, World Health Organization (WHO), together with International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC), developed research protocols facilitating global collaboration and accelerating the understanding of the disease, to identify the potential symptoms and persistent sequelae in infected individuals, which can be used in different areas of health, that is, in primary care, at a hospital or outpatient level, both public and private. Objective: To describe the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) protocol as a new global collaborative platform for global clinical trials targeting post-COVID-19 patients. Methods: The standardized forms were developed from the COVID-19 Clinical Characterization Protocol (PCC) by the ISARIC/WHO working group composed of specialist researchers with experience in clinical research in different areas of medicine and public health, especially outbreaks and infectious diseases. Conclusion: It is expected that the creation of a database composed of different populations from all over the world will help in the characterization of risk factors, in the best form of clinical intervention and in the best prevention strategies for physical, neurological and psychosocial sequelae in the medium and long term in post-COVID-19 patients.  

Extended coagulation profile of children with Long Covid: a prospective study

Emerging data suggests that endotheliopathy changes can be associated with post covid condition (PCC) in adults. Research on the matter in children is lacking. We analyzed an extended coagulation profile including biomarkers of endothelial damage in children with PCC and compared it with a control group of children that fully recovered post- SARS-CoV-2 infection. A case-control study enrolling children below 18 years of age with previous microbiologically confirmed SARS-CoV-2 infection in a pediatric post-covid unit in Italy ≥ 8 weeks after the initial infection. Samples were taken at 8 and 12 weeks after the SARS-CoV-2 diagnosis and analyzed for coagulation profiling (fibrinogen, prothrombin time, international normalized ratio, activated partial thromboplastin time, d-dimers, factor VIII coagulant activity, plasma von Willebrand factor (VWF) antigen and VWF ristocetin cofactor (RC)). We compared coagulation profiles in samples from children identified with PCC (at least one, or three or more symptoms, which could not be explained by an alternative diagnosis, at the 8- and 12-week follow-up assessment using the pediatric Long Covid International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) survey. Seventy-five children were enrolled, 49.3% were females, the median age was 10.2 (IQR 4.9) years. Forty-six (61%) of the children had at least one persisting symptom at the eight weeks post-onset, (PCC8); 39/75 (52%) had persistent symptoms for more than 12 weeks (PCC12) and 15/75(32%) had at least three persisting symptoms (PCC ≥ 3) at 12 weeks. Children with PCC presented more frequently with abnormal D-Dimer levels above the reference range compared to children that had fully recovered at the 8–12 weeks (39.1% vs. 17.2%, p = 0.04), and 12 week follow up or more (41% vs. 17.2%, p = 0.05), and in children with three or more symptoms at 12 weeks follow up compared to those that had recovered (64.3% vs. 22.2%, p = 0.002). For the other coagulation profiles, there were abnormal values detected for VWF, FVIII, RC and Fibrinogen but no significant differences between children with PCC compared to controls. Although the majority of children in our cohort showed coagulation profile within or close to normal ranges, we found that a higher proportion of children with PCC, and specifically those with a more severe spectrum characterized with three or more persisting symptoms, had abnormal D-dimer levels compared to other children that fully recovered from an acute SARS-CoV-2 infection.

Paediatric COVID-19 mortality: a database analysis of the impact of health resource disparity

BackgroundThe impact of the COVID-19 pandemic on paediatric populations varied between high-income countries (HICs) versus low-income to middle-income countries (LMICs). We sought to investigate differences in paediatric clinical outcomes and...

ISARIC-COVID-19 dataset: A Prospective, Standardized, Global Dataset of Patients Hospitalized with COVID-19

The International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) COVID-19 dataset is one of the largest international databases of prospectively collected clinical data on people hospitalized with COVID-19. This dataset was compiled during the COVID-19 pandemic by a network of hospitals that collect data using the ISARIC-World Health Organization Clinical Characterization Protocol and data tools. The database includes data from more than 705,000 patients, collected in more than 60 countries and 1,500 centres worldwide. Patient data are available from acute hospital admissions with COVID-19 and outpatient follow-ups. The data include signs and symptoms, pre-existing comorbidities, vital signs, chronic and acute treatments, complications, dates of hospitalization and discharge, mortality, viral strains, vaccination status, and other data. Here, we present the dataset characteristics, explain its architecture and how to gain access, and provide tools to facilitate its use.

Mapping of SARS-CoV-2 IgM and IgG in gingival crevicular fluid: Antibody dynamics and linkage to severity of COVID-19 in hospital inpatients

•Gingival crevicular fluid forms a useful analyte for detecting SARS-CoV-2 antibody.•There are differential patterns of antibody reactivity across NP and Spike.•Higher antibody levels in early acute phase linked to severity of COVID-19. IntroductionThe use of non-venous analytes has been a priority public health tool for the diagnosis, monitoring and surveillance of a range of pathogens. These methods, primarily based on Dried Blood Spots (DBS) and Gingival Crevicular Fluid (GCF), were first developed in the UK and have been applied to investigate outbreak and transmission events,1Haywood B. Tedder R.S. Beebeejaun K. Balogun K. Mandal S. Andrews N. et al.Oral fluid testing facilitates understanding of hepatitis A virus household transmission.Epidemiol Infect. 2019; 147: e105Crossref PubMed Scopus (1) Google Scholar,2Glynn J.R. Bower H. Johnson S. Houlihan C.F. Montesano C. Scott J.T. et al.Asymptomatic infection and unrecognised Ebola virus disease in Ebola-affected households in Sierra Leone: a cross-sectional study using a new non-invasive assay for antibodies to Ebola virus.Lancet Infect Dis. 2017; 17: 645-653Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar to improve the diagnosis of infections in underserved populations3Craine N. Parry J. O'Toole J. D'Arcy S. Lyons M. Improving blood-borne viral diagnosis; clinical audit of the uptake of dried blood spot testing offered by a substance misuse service.J Viral Hepat. 2009; 16: 219-222Crossref PubMed Scopus (34) Google Scholar,4Dodds J.P. Johnson A.M. Parry J.V. Mercey D.E. A tale of three cities: persisting high HIV prevalence, risk behaviour and undiagnosed infection in community samples of men who have sex with men.Sex Transm Infect. 2007; 83: 392-396Crossref PubMed Scopus (54) Google Scholar in addition to monitoring infection trends and informing on the impact of interventions.5Bardsley M. Heinsbroek E. Harris R. Croxford S. Edmundson C. Hope V. et al.The impact of direct-acting antivirals on hepatitis C viraemia among people who inject drugs in England; real-world data 2011–2018.J Viral Hepat. 2021; 28: 1052-1463Crossref Scopus (3) Google Scholar,6Judd A. Hickman M. Hope V.D. Sutton A.J. Simson G.V. Ramsay M.E. et al.Twenty years of selective hepatitis B vaccination: is hepatitis B declining among injecting drug users in England and Wales?.J Viral Hepat. 2007; 14: 584-591Crossref PubMed Scopus (19) Google ScholarThe ability to use non-venous analytes for antigen, antibody and nucleic acid detection and characterisation has applications to answer questions linked to SARS-CoV-2 infections. The virus has been shown to transmit efficiently between individuals and within communities,7Miller E. Waight P.A. Andrews N.J. McOwat K. Brown K.E. Höschler K. et al.Transmission of SARS-CoV-2 in the household setting: a prospective cohort in children and adults in England.J Infect. 2021; 83: 483-489Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar, 8Adam D.C. Wu P. Wong J.Y. Lau E.H.Y. Tsang T.K. Cauchemez S. et al.Clustering and superspreading potential of SARS-CoV-2 infections in Hong Kong.Nat Med. 2020; 26: 1714-1719Crossref PubMed Scopus (280) Google Scholar, 9Payne D.C. Smith-Jeffcoat S.E. Nowak G. Chukwuma U. Geibe J.R. Hawkins R.J. et al.SARS-CoV-2 infections and serologic responses from a sample of US navy service members – USS Theodore Roosevelt, April 2020.Morb Mortal Wkly Rep. 2020; 69: 714-721Crossref PubMed Google Scholar, 10Jeffery-Smith A. Dun-Campbell K. Janarthanan R. Fok J. Crawley-Boevey E. Vusirikala A. et al.Infection and transmission of SARS-CoV-2 in London care homes reporting no cases or outbreaks of COVID-19: prospective observational cohort study, England 2020.Lancet Reg Health Eur. 2021; 3100038PubMed Google Scholar with the rapid spread of SARS-CoV-2 attributed to transmissions from asymptomatic but infected individuals.10Jeffery-Smith A. Dun-Campbell K. Janarthanan R. Fok J. Crawley-Boevey E. Vusirikala A. et al.Infection and transmission of SARS-CoV-2 in London care homes reporting no cases or outbreaks of COVID-19: prospective observational cohort study, England 2020.Lancet Reg Health Eur. 2021; 3100038PubMed Google Scholar, 11Ye F. Xu S. Rong Z. Xu R. Liu X. Deng P. Liu H. Xu X. Delivery of infection from asymptomatic carriers of COVID-19 in a familial cluster.Int J Infect Dis. 2020; 94: 133-138Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar, 12Zhou R. Li F. Chen F. Liu H. Zheng J. Lei C. Wu X. Viral dynamics in asymptomatic patients with COVID-19.Int J Infect Dis. 2020; 96: 288-290Abstract Full Text Full Text PDF PubMed Scopus (135) Google Scholar, 13Putallaz P. Senn L. Bosshard W. Büla C.J. COVID-19 outbreak at a geriatric rehabilitation facility: the silent threat of asymptomatic patients with high viral loads.Geriatrics. 2021; 6 (Basel): 95Crossref PubMed Scopus (1) Google Scholar, 14Glenet M. Lebreil A.L. Heng L. N'Guyen Y. Meyer I. Andreoletti L. Asymptomatic COVID-19 adult outpatients identified as significant viable SARS-CoV-2 shedders.Sci Rep. 2021; 11: 20615Crossref PubMed Scopus (4) Google Scholar The ease of sampling with non-venous analytes and the ability for self-collection allows for rapid and accessible individual and population-based diagnostics and monitoring of prevalence. The convenience and acceptability of sample collection permit population prevalence studies, for example in school children or in immunised self-isolating individual populations, providing an important mechanism for generating data for virus surveillance with a potential to inform policy. A key role of population antibody testing would be to characterise the relationship between the development and dynamics of antibody responses to infection, vaccination, and the impact of the measures on subsequent rates of transmission.Enzyme linked immunoassays formatted for immunoglobulin (Ig) capture onto the solid phase are favoured for the analysis of non-venous analytes. In this study, we compare the application of Immunoglobulin class M (IgM) and Immunoglobulin class G (IgG) Ig-capture assays to detect antibody against the Nucleoprotein and components of the Spike protein on paired GCF and sera to characterise the acute and early convalescent antibody responses in hospitalised patients with COVID-19 in the UK, and correlate antibody reactivity with severity of disease.Materials and methodsStudy setting and approvalsThe International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC) WHO Clinical Characterisation Protocol UK (CCP-UK) study is an ongoing, prospective cohort study recruiting inpatients with COVID-19 from 348 hospital sites in England, Wales, Scotland, and Northern Ireland.15Docherty A.B. Harrison E.M. Green C.A. Hardwick H.E. Pius R. Norman L. et al.Semple MG, ISARIC4C Investigators. Features of 20 133 UK patients in hospital with COVID-19 using the ISARIC WHO clinical characteristics protocol: prospective observational cohort study.BMJ. 2020; 369: m1985Crossref PubMed Scopus (1574) Google Scholar Ethics approval was granted by the South Central—Oxford C Research Ethics Committee in England (13/SC/0149), the Scotland A Research Ethics Committee (20/SS/0028), and the WHO Ethics Review Committee (RPC571 and RPC572; April 2013). The study protocol and further details are available at https://isaric4c.net/protocols/.15Docherty A.B. Harrison E.M. Green C.A. Hardwick H.E. Pius R. Norman L. et al.Semple MG, ISARIC4C Investigators. Features of 20 133 UK patients in hospital with COVID-19 using the ISARIC WHO clinical characteristics protocol: prospective observational cohort study.BMJ. 2020; 369: m1985Crossref PubMed Scopus (1574) Google ScholarStudy participantsRecruitment procedures for the ISARIC WHO CCP-UK study have been described previously.15Docherty A.B. Harrison E.M. Green C.A. Hardwick H.E. Pius R. Norman L. et al.Semple MG, ISARIC4C Investigators. Features of 20 133 UK patients in hospital with COVID-19 using the ISARIC WHO clinical characteristics protocol: prospective observational cohort study.BMJ. 2020; 369: m1985Crossref PubMed Scopus (1574) Google Scholar Briefly, baseline demographic information and key clinical data including patient characteristics, symptom onset dates, illness severity, level of respiratory support, COVID-19-specific treatment and outcome were recorded in case report forms on a REDCap database. Samples included in this study were collected between March 2020 and June 2020 and were from 115 inpatients across five hospitals. A breakdown of patient numbers from hospitals 1 to 5 were as follows n = 53, n = 15, n = 8, n = 24 and n = 15, respectively. With consent, biological samples, including GCF and sera, were collected from recruited patients on days 1, 3, 9 and 28 post-enrolment. Samples from all four time-points were not available for all patients due to prioritisation of delivery of care over research activity early in infection or later hospital discharge or death. Only patients with matched GCF and serum samples were included in this analysis. Patients with missing data on symptom onset date were excluded. Collated data were analysed with overall trends presented.Patients were grouped into five categories of peak illness severity based on the World Health Organization (WHO) COVID-19 ordinal scale16WHO R&D Blueprint. Novel Coronavirus, COVID-19 Therapeutuc Trial Synopsis. February 18, 2020. Available at:https://cdn.who.int/media/docs/default-source/blue-print/covid-19-therapeutic-trial-synopsis.pdf?sfvrsn=44b83344_1&download=true. Accessed June 2022Google Scholar: (i) no oxygen requirement (WHO score 3); (ii) patient requiring oxygen by face mask or nasal prongs (WHO score 4); (iii) patient requiring high-flow nasal oxygen (HFNO) or non-invasive ventilation (NIV) (WHO score 5); (iv) patients requiring mechanical ventilation (WHO score 6/7) and (v) patients who died in hospital within 28 days of admission (WHO score 8).Collection and extraction of gingival crevicular fluid (GCF) from oracoltm swabsGingival crevicular fluid samples were collected by study staff by brushing Oracol™ S14 foam swabs (Malvern Medical Developments, Worcester, UK) along the upper and lower gumlines, ie the junction between the teeth and the gum, of both sides of a patient's mouth for a total of two minutes. The collected swabs were then frozen at −20 °C. On receipt in the laboratory, the GCF was extracted from the foam swab by adding 1 ml of elution buffer (Phosphate buffered saline containing 10% Foetal Calf Serum, 0.1% Tween-20, 0.5 µg/ml Fungizone and 250 µg/ml Gentamicin). The elution buffer was then moved through the foam by squeezing and agitating the swab against the swab tube wall for approximately 30 s. The swab was then placed directly into the open cap and the cap replaced in the swab tube. The swab was centrifuged at 2000 rpm for five minutes, then removed and discarded. The eluted GCF was transferred into a 2 ml Sarstedt™ tube and stored at −20 °C prior to testing.S1, Spike and NP IgM and IgG capture ELISAsImmunoglobulin capture assays for the detection of IgM and IgG were established for three targets: S1, whole Spike and NP. Horseradish peroxidase (HRP) conjugated SARS-CoV-2 full length Spike Glycoprotein (amino acids 1–1211; His-tag) and Nucleoprotein (amino acids 1–149; His-tag) were purchased from The Native Antigen Company (Kidlington, Oxford, UK). The SARS-CoV-2 S1 antigen (amino acid 1–530, C-terminal twin Strep tags)17Rosa A. Pye V.E. Graham C. Muir L. Seow J. Ng K.W. et al.SARS-CoV-2 can recruit a heme metabolite to evade antibody immunity.Sci Adv. 2021; 7: eabg7607Crossref PubMed Scopus (39) Google Scholar was produced and gifted by The Francis Crick Institute and conjugated to HRP using the Bio-Rad LYNX HRP conjugation kit, in accordance with the manufacturer's instructions. All three recombinant proteins were based on the original Victoria lineage.Solid-phase wells (NUNC® Immunomodule, U8 Maxisorp™ wells) were coated with 100μl volumes of (a) Affinipure rabbit anti-human ɣ (Jackson ImmunoResearch, Ely, Cambridgeshire UK) at 5 μg/ml or (b) Affinpure goat anti-human IgM, Fc5µ fragment (Jackson ImmunoResearch, Ely, Cambridgeshire UK) at 2.5 μg/ml in MicroImmune Coating Buffer for ELISA with preservative; (ClinTech, Guildford, UK). Coating was overnight at 2–8 °C, followed by 3 h at 35–37 °C. Wells were then washed with PBS Tween 20 and quenched with MicroImmune Blocking Solution (ClinTech, Guildford, UK) for 3–4 h at 37 °C. Wells were aspirated and stored dry at 4 °C in sealed pouches with desiccant until use.For these Ig capture ELISAs, 100 µl of GCF or 100 µl of a 1:100 dilution of the serum sample in elution buffer were added to the well, incubated for 60 ± 2 min at 37 °C prior to washing and the addition of the conjugate. One hundred microlitres of the HRP-conjugated recombinant protein for each individual assay were added to the microwells. After a further incubation for 60 ± 2 min at 37 °C, the solid phase was washed and 100 µl of TMB substrate added, incubated for 30 ± 2 min at 37 °C, the reaction was then stopped and measured at 450/630 nm. The cut off was calculated as the mean of 4x negative controls +0.1. Samples with a binding ratio (Sample/Cut Off) of ≥1.0 were considered to be antibody reactive. The GCF IgG assays have a specificity of 98% with a sensitivity of 79%, 75% and 70% for S1, NP and whole Spike tests, respectively.18Hoschler K. Ijaz S. Andrews N. Ho S. Dicks S. Jegatheesan K. et al.SARS antibody testing in children: development of oral fluid assays for IgG measurements.Microbiol Spectr. 2022; 10 (Jan 5)e0078621Crossref PubMed Scopus (6) Google Scholar Assay validation data including assignment of test cut off, correlation between GCF and serum and the impact of total IgG in GCF samples have been previously described.18Hoschler K. Ijaz S. Andrews N. Ho S. Dicks S. Jegatheesan K. et al.SARS antibody testing in children: development of oral fluid assays for IgG measurements.Microbiol Spectr. 2022; 10 (Jan 5)e0078621Crossref PubMed Scopus (6) Google ScholarEndemic seasonal coronavirus NP blockingTo mitigate potential issues with cross reactivity in the NP capture assay, four recombinant seasonal coronavirus nucleoproteins (229E, NL63, OC43 and HKU1), produced and gifted by The Francis Crick Institute, were added to the final SARS-CoV-2 NP conjugate. The seasonal NP antigens were added ‘cold’, ie unconjugated, and acted to block non-specific reactivity, a concept that has been previously described for flavivirus serology.19Tedder R.S. Dicks S. Ijaz S. Santiago de Souza N.C. Vincente de Paula A. Levy F. et al.Ushiro lumb I. Modulated Zika virus NS1 conjugate offers advantages for accurate detection of Zika virus specific antibody in double antigen binding and Ig capture enzyme immunoassays.PLoS ONE. 2019; 14e0215708Crossref PubMed Scopus (4) Google Scholar To demonstrate utility, each seasonal coronavirus NP recombinant protein was added individually and also as a four-mix combination at a final concentration of 2.5 µg/ml to the SARS-CoV-2 NP conjugate and tested on pre-pandemic samples reactive in the unblocked SARS-CoV-2 NP assay.ResultsMatched GCF and serum samples were available from 115 inpatients admitted with COVID-19. Patient characteristics are described in Supplementary Table 1. Of these patients, 34% were in severity group 1, 27% in group 2, 9% in group 3, 15% in group 4, and 14% in group 5. As expected, differences between the severity groups were noted with the overall trend for females to have lower disease severity scores than males. A total of 320 matched samples (160 GCF and 160 serum samples) were included in this analysis.Endemic seasonal coronavirus NP blockingSerum samples collected from patients with confirmed SARS-CoV-2 infection remained IgG antibody reactive in the presence of the blocking antigens when endemic seasonal coronavirus nucleoproteins were added either individually or in combination (Table 1). Some reduction in reactivity was noted when compared to the unblocked wells (Table 1). False positive reactivity observed in samples 5 to 9 was efficiently blocked with the addition of the nucleoproteins from coronavirus 229E and NL63 as well as in the test where all four endemic coronavirus nucleoproteins were added (Table 1).Table 1. ‘Blocking’ data on the NP IgG capture assay; OD values shown in bold indicate reactive samples. Each seasonal coronavirus NP was added individually and also as a four mix combination at a final concentration of 2.5 µg/ml to the SARS-CoV-2 NP conjugate and tested on samples identified to be SARS-CoV-2 antibody positive samples (samples 1 to 4) and pre-pandemic samples reactive in the unblocked SARS-CoV-2 NP assay (samples 5 to 14).SamplesNP IgG Capture Assay (OD)No Block229E BlockNL63 BlockOC43 BlockHKU1 BlockAll 4 BlockSARS-CoV-2 SamplesSample 11.1840.9520.9541.0991.0350.926Sample 22.7222.1582.2112.2512.1662.075Sample 31.2121.0771.1421.1721.0641.019Sample 41.2881.2431.2821.2420.9640.981Samples collected pre-pandemicSample 50.2550.0750.0720.2380.2710.061Sample 60.2780.0890.0970.1570.1980.053Sample 70.2880.0740.060.1160.330.051Sample 80.2340.0590.0580.1940.1960.068Sample 90.330.0560.0510.330.3310.055Sample 100.0880.0360.0360.0330.0730.086Sample 110.0530.0370.040.0410.0570.079Sample 120.1370.1010.1020.1140.150.061Sample 130.0910.0580.0630.0670.0920.051Sample 140.0840.0440.0410.0470.1510.087 Open table in a new tab Development of early antibody responses as measured in gingival crevicular fluid collected from hospital inpatientsAccess to samples collected in the 21 days after symptom onset allowed for the mapping of the early antibody responses in GCF samples. The overall trend across the three proteins from day zero through to day 21, was a rise in antibody reactivity levels (Fig. 1; Table 2) and an increase in the number of reactive samples (Table 2). Differential reactivity was noticeable across the proteins with a higher proportion of samples collected in the 14 days after symptom onset being reactive for anti-NP compared to that displayed for antibody to the Spike and S1 antigens. This was noted for both the IgM and IgG class antibodies (Table 2). The data indicated antibodies (IgM with or without IgG) are detectable in GCF within the first seven days from symptom onset (Table 2). Across the two Spike assays, 21–26%, 49–53%, and 78–82% of the samples were IgM reactive and 15–18%, 35–43%, and 56–78% were IgG reactive by day 7, 14 and 21, respectively. For the NP assay, 42%, 65%, and 65% of the samples were IgM reactive and 42%, 67%, and 87% were IgG reactive by day 7, 14 and 21, respectively.Table 2Development of antibody responses as measured against three recombinant proteins, whole spike, NP and S1, in matched GCF and serum samples collected from hospitalised patients. The percentage of samples antibody reactive (IgM and IgG) and median binding ratios (sample OD/cut off) for each analyte is shown across the early stages of infection (days 0–21 post symptom onset) and at >22 days (range: 22–80 days).Days post symptom onsetOral FluidSerumIgMIgGIgMIgGSpikeNPS1SpikeNPS1SpikeNPS1SpikeNPS1% antibody reactive samples0 to 721.142.126.318.442.115.834.250.044.723.742.128.98 to 1449.365.753.035.867.243.964.265.766.750.762.751.515 to 2178.365.282.678.387.056.5100.095.7100.095.795.7100.0> 2256.846.865.671.887.571.884.375.090.675.090.681.2median binding ratios0 to 71.372.111.871.883.811.753.034.475.472.484.952.778 to 142.63.053.822.645.182.926.775.819.564.988.777.2715 to 214.694.508.605.519.004.8110.508.3218.3210.8716.2113.80> 221.750.753.746.4210.505.287.404.8113.9010.2813.7113.10 Open table in a new tab Antibody dynamics in GCF samplesThe trend was for IgM reactivity to peak by week three after symptom onset in all assays. Overall, a more robust IgM response was noted on tests based on S1 and Spike compared to the NP assay. In the 32 samples collected after week three of symptom onset (range: 22–80 days), a decline in IgM reactivity levels was noted for antibody to all three antigens, this decrease being more marked for the NP protein (Fig. 1, Table 2). The overall trend was for IgG antibody reactivity to continue to rise even in the samples collected after day 22 of symptom onset. However, although reactivity in the S1 and Spike based assays did not increase after week three of symptom onset; a rise in median binding ratios was observed with the anti-NP assay.Comparative analysis of binding ratios across the three recombinant proteins indicated a good correlation in the two Spike based assays with both IgM and IgG (Fig. 2A). This relationship was less defined when comparing the NP to the two Spike assays (Fig. 2B,C), in particular for IgM where there was a notable trend for lower reactivity in the NP IgM assay.Fig. 2. X/Y plots demonstrating the correlation of IgM and IgG responses in GCF samples across three proteins; between S1 and Spike (A), NP and Spike (B) and NP and S1 (C). Binding ratios (BR; sample OD/cut off) have been logged.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Antibody levels in GCF stratified by disease severity scoreAntibody binding ratios were mapped against days from symptoms onset (Fig. 3A,C). A broad distribution of antibody binding ratios was noted across the three SARS-CoV-2 protein targets in both the IgM and IgG assays. The data plot was divided into nine grids split by antibody binding ratio levels (Low [L], Medium [M], High [H]) and across the days post symptom onset (Early: 0–14 days, Middle: 15–30 days and Late: 31–50 days). These data were mapped onto the corresponding severity score for each patient to investigate possible associations. Only the initial sample collected from each patient was included in this analysis with the majority of samples falling into the grids representing the early antibody response. The data suggested increased severity of disease severity scores to be linked to those patients whose samples displayed high antibody levels (H), in particular in the first 14 days post symptom onset (Fig. 3B,C). This trend was seen across all three protein targets and also for both IgM and IgG with some suggestion that the association with increased severity to be more marked in the IgM response. This observation was maintained in the middle phase (15–30 days post symptom onset), although not reaching statistical significance in all instances.Fig. 3Distribution of antibody binding ratios across the three protein targets in both the IgM and IgG assays. In panels A (IgM) and C (IgG), the data is divided into nine grids split by binding ratio levels (Low [L], Medium [M], High [H]) and across the observation period (days) post symptom onset (Early, Middle and Late). In panels B (IgM) and D (IgG), violin plots demonstrate relationships between antibody reactivity levels and disease severity demonstrating that earlier in disease higher antibody levels are associated with more severe disease. The first measurement for each patient was included in the analysis and the Kruskal-Wallis statistical test accounting for multiple testing was implemented.View Large Image Figure ViewerDownload Hi-res image Download (PPT)More limited sample numbers in the late phase restricted analysis and interpretation of the data.Antibody dynamics in matched serum samplesTesting of serum samples showed broadly comparable antibody reactivity trends to the matched GCF samples. This was observed for both IgM and IgG assays and across the three proteins (Table 2; Fig. S1). Positive antibody reactivity was shown to occur earlier in serum samples. As expected, antibody reactivity levels were higher in serum than the matched GCF samples (Table 2; Fig. S1). As with GCF samples, differential reactivity was observed between the NP and Spike and S1 assays in serum samples collected in the first 14 days after symptom onset.DiscussionThere has been a rapid evolution of antibody diagnostics over the course of the COVID19 pandemic encompassing a range of assay formats and investigating multiple targets. Whilst serum/plasma samples remain the gold standard for antibody detection, other non-venous analytes including DBS20Turgeon C.T. Sanders K.A. Granger D. Nett S.L. Hilgart H. Matern D. et al.Detection of SARS-CoV-2 IgG antibodies in dried blood spots.Diagn Microbiol Infect Dis. 2021; 101115425Crossref PubMed Scopus (11) Google Scholar, 21Marchand A. Roulland I. Semence F. Beck O. Ericsson M. Use of quantitative dried blood spots to evaluate the post-vaccination level of neutralizing antibodies against SARS-CoV-2.Life. 2021; 11 (Basel): 1125Crossref PubMed Scopus (4) Google Scholar, 22Beyerl J. Rubio-Acero R. Castelletti N. Paunovic I. Kroidl I. Khan Z.N. et al.A dried blood spot protocol for high throughput analysis of SARS-CoV-2 serology based on the Roche Elecsys anti-N assay.EBioMedicine. 2021; 70103502Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar and saliva23Vilela A.C.S. Costa C.A. Oliveira S.A. Souza M.B.L.D. Fiaccadori F.S. Leles C.R. et al.Validity and reliability of immunochromatographic IgM/IgG rapid tests for COVID-19 salivary diagnosis.Oral Dis. 2021; https://doi.org/10.1111/odi.14059Crossref PubMed Scopus (2) Google Scholar, 24Egorov A.I. Griffin S.M. Fuzawa M. Kobylanski J. Grindstaff R. Padgett W. et al.A multiplex noninvasive salivary antibody assay for SARS-CoV-2 infection and its application in a population-based survey by mail.Microbiol Spectr. 2021; 9e0069321Crossref PubMed Scopus (6) Google Scholar, 25Chiang S.H. Tu M. Cheng J. Wei F. Li F. Chia D. et al.Development and validation of a quantitative, non invasive, highly sensitive and specific, electrochemical assay for anti-SARS-CoV-2 IgG antibodies in saliva.PLoS ONE. 2021; 16e0251342Crossref Scopus (6) Google Scholar have been successfully utilised for the detection and monitoring of antibody responses. Gingival crevicular fluid has some useful advantages over these analytes. The collection of GCF is less invasive than DBS and may be better suited for sample collection in specific populations such as children. In addition, as GCF, obtained as we describe using oral fluid collection swabs, is derived directly by transudation from blood plasma, immunoglobulin levels may be higher when compared to that in saliva.The assays applied in this study are based on antibody capture formats which have been primarily used for antibody detection methods based on GCF.Being proportionality assays they are less affected by variability in sample quality and the quantity of Ig therein contained, a feature which may be associated with the collection of various non-venous analytes. Due to the close homology shared between the NP of SARS-CoV-2 and the NP of endemic seasonal coronaviruses, NP IgM and IgG capture assay based on the concept of blocking were established. The observed blocking patterns were specific as false reactivity detected in five samples collected pre-pandemic was blocked by the alphacoronavirus NP antigens (229E and NL63) but not the betacoronavirus NP antigens (OC43 and HKU1) (Table 1). Some reduction in reactivity was noted in serum samples collected from confirmed SARS-CoV-2 infected patients in the presence of the blocking antigens. However, this was not unexpected due to blocking of NP epitopes common across the coronavirus family. All recombinant proteins in our investigation were based on the original Victoria lineage. This would have been the common SARS-CoV-2 virus circulating at the time the samples included in our investigation were collected. With emerging new variants, consideration will need to be given to the choice of recombinant proteins in particular those based on the S1 with additional verification needed to ensure sensitivity.Mapping of the early antibody response indicated IgM and IgG reactivity to be detectable in GCF samples as early as week one post onset of symptoms with antibody reactivity levels, and the proportion of reactive samples increasing through weeks two and three. The overall trends were mirrored across both GCF and serum analytes demonstrating the utility of GCF for the detection and monitoring of the early antibody response.Differential patterns of antibody reactivity across the NP and the Spike based proteins were noted. Antibody responses to NP were found to appear earlier, a trend noted in both the serum and GCF analytes and for both the IgM and IgG antibody classes. These observations are in line with what has been previously described with serum as the main analyte.26Brochot E. Demey B. Touzé A. Belouzard S. Dubuisson J. Schmit J.L. Anti-spike, anti-nucleocapsid and neutralising antibodies in SARS-CoV-2 inpatients and asymptomatic individuals.Front Microbiol. 2020; 11584251Crossref PubMed Scopus (77) Google Scholar Brochot and colleagues,26Brochot E. Demey B. Touzé A. Belouzard S. Dubuisson J. Schmit J.L. Anti-spike, anti-nucleocapsid and neutralising antibodies in SARS-CoV-2 inpatients and asymptomatic individuals.Front Microbiol. 2020; 11584251Crossref PubMed Scopus (77) Google Scholar examining time to seroconversion, also demonstrated differences in antibody dynamics between various spike proteins. Antibodies targeting the receptor binding domain (anti-RBD) were the earliest to be detected with anti-RBD profiles mirroring the antibody responses to NP. Anti-S2 antibodies followed with a mean time lag of two days; antibodies to the S1 subunit were the last to be detected. The report also no

EFFICACY OF REMDESIVIR VERSUS REMDESIVIR PLUS TOCILIZUMAB IN MODERATE TO SEVERE COVID-19 PATIENTS ADMITTED IN THE CRITICAL CARE UNIT OF A TERTIARY CARE HOSPITAL IN WEST BENGAL, INDIA

Background And Aims: Severe corona virus infection is often associated with hyper immune response and liberation of inammatory cytokines. Anti-interleukin-6 receptor monoclonal antibody like tocilizumab might be effective in corona virus infection. Present study was designed to assess the effect of adding tocilizumab to remdesivir and other supportive therapy in management of critically ill covid-19 patients. Methods: This Randomized open-level clinical trial was done in 50 critically ill Covid-19 patients (from December 2020 to February 2021). They were randomly allocated in two group; to receive either injection remdesivir (Group R) or injection remdesivir plus tocilizumab (Group RT) intravenously. Patients were assessed using daily record sheets capturing data on the six-category ordinal scale and safety prole from day-1 to day28 or discharge or death. Other clinical data were recorded using the WHO International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) case record form. Primary endpoint with respect to the efcacy of the drugs was based on proportion of patients achieving clinical improvement dened as a two point reduction in six point ordinal scale from patients admission status or live discharge from the hospital, which ever came rst. Results: Baseline characteristics were identical in both R and RT group. Biomarkers, C reactive protein, IL-6 and serum ferritin levels were signicantly more in RT group as compared to R group on day 1,3 and 7. But C reactive protein (CRP), serum ferritin and IL-6 levels from day 1 to day 7 gradually decreased in RT group and increased in R group. Conclusion: In spite of higher levels of biomarkers morbidity and mortality of patients did not increase in RT group; use of tocilizumab might be responsible for the gradual reduction in the level of biomarkers in this group.

Use of an extended KDIGO definition to diagnose acute kidney injury in patients with COVID-19: A multinational study using the ISARIC-WHO clinical characterisation protocol.

Acute kidney injury (AKI) is one of the most common and significant problems in patients with Coronavirus Disease 2019 (COVID-19). However, little is known about the incidence and impact of AKI occurring in the community or early in the hospital admission. The traditional Kidney Disease Improving Global Outcomes (KDIGO) definition can fail to identify patients for whom hospitalisation coincides with recovery of AKI as manifested by a decrease in serum creatinine (sCr). We hypothesised that an extended KDIGO (eKDIGO) definition, adapted from the International Society of Nephrology (ISN) 0by25 studies, would identify more cases of AKI in patients with COVID-19 and that these may correspond to community-acquired AKI (CA-AKI) with similarly poor outcomes as previously reported in this population. All individuals recruited using the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC)-World Health Organization (WHO) Clinical Characterisation Protocol (CCP) and admitted to 1,609 hospitals in 54 countries with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection from February 15, 2020 to February 1, 2021 were included in the study. Data were collected and analysed for the duration of a patient's admission. Incidence, staging, and timing of AKI were evaluated using a traditional and eKDIGO definition, which incorporated a commensurate decrease in sCr. Patients within eKDIGO diagnosed with AKI by a decrease in sCr were labelled as deKDIGO. Clinical characteristics and outcomes-intensive care unit (ICU) admission, invasive mechanical ventilation, and in-hospital death-were compared for all 3 groups of patients. The relationship between eKDIGO AKI and in-hospital death was assessed using survival curves and logistic regression, adjusting for disease severity and AKI susceptibility. A total of 75,670 patients were included in the final analysis cohort. Median length of admission was 12 days (interquartile range [IQR] 7, 20). There were twice as many patients with AKI identified by eKDIGO than KDIGO (31.7% versus 16.8%). Those in the eKDIGO group had a greater proportion of stage 1 AKI (58% versus 36% in KDIGO patients). Peak AKI occurred early in the admission more frequently among eKDIGO than KDIGO patients. Compared to those without AKI, patients in the eKDIGO group had worse renal function on admission, more in-hospital complications, higher rates of ICU admission (54% versus 23%) invasive ventilation (45% versus 15%), and increased mortality (38% versus 19%). Patients in the eKDIGO group had a higher risk of in-hospital death than those without AKI (adjusted odds ratio: 1.78, 95% confidence interval: 1.71 to 1.80, p-value < 0.001). Mortality and rate of ICU admission were lower among deKDIGO than KDIGO patients (25% versus 50% death and 35% versus 70% ICU admission) but significantly higher when compared to patients with no AKI (25% versus 19% death and 35% versus 23% ICU admission) (all p-values <5 × 10-5). Limitations include ad hoc sCr sampling, exclusion of patients with less than two sCr measurements, and limited availability of sCr measurements prior to initiation of acute dialysis. An extended KDIGO definition of AKI resulted in a significantly higher detection rate in this population. These additional cases of AKI occurred early in the hospital admission and were associated with worse outcomes compared to patients without AKI.

Prevalence of bacterial coinfection and patterns of antibiotics prescribing in patients with COVID-19: a systematic review and meta-analysis

IntroductionEvidence on prevalence of bacterial coinfection in Coronavirus Disease 2019 (COVID-19) is controversial; previous global viral respiratory pandemics reported high prevalence of bacterial coinfection, which was associated with increased risk of morbidity and mortality (1). Data on Prevalence of antibiotic prescribing in COVID-19 indicates high antibiotic prescribing, causing a potential setback in antimicrobial stewardship and potential increase in antimicrobial resistance (2). The study protocol was registered in the international register of systematic reviews, PROSPERO, under the following ID: CRD42021261734AimTo determine the prevalence of bacterial coinfection and antibiotic prescribing in COVID-19 patientsMethodsSystematic review and meta-analysis was conducted using Covidence. Data were extracted by one reviewer. Proportion data was pooled using random effects meta-analysis approach using STATA 17; and stratified based on region and study design. Data Source: OVID MEDLINE, OVID EMBASE, Cochrane and MedRxiv between January 2020 and June 2021. Study Eligibility: English language studies of laboratory-confirmed COVID-19 patients which reported (a) prevalence of bacterial coinfection and/or (b) prevalence of antibiotic prescribing with no restrictions to study designs or healthcare setting. Participants: Adults with RT-PCR confirmed diagnosis of COVID-19ResultsA total of 1058 studies were screened, of which 22 studies were eligible. Retrospective cohort studies accounted for the majority of the studies involved (n = 18, 81%), whilst prospective cohort studies accounted for the remaining (n=4, 18%). Of the 22 studies included, 3 (13%) studies were pre-prints, whilst the remaining (n=19, 86%) were peer-reviewed. A total of 13 (59%) studies were conducted in multicentre settings, whilst the remaining (n=9, 40%) were conducted in single centre settings. All of the studies included were conducted in hospital setting, whether it be in a normal, isolation or an intensive care ward. Twenty-one out of 22 studies have been rated “Good” rating during the quality assessment process. Pooled estimates for the prevalence of bacterial co-infection and antibiotic use were 5.62% (95% CI 2.26 – 10.31) and 61.77% (CI 50.95 – 70.90), respectively.ConclusionThe prevalence of bacterial coinfection amongst COVID-19 patients is low (5.62%) when compared with previous pandemics, yet antibiotic prescribing in COVID-19 patients was high (61.77%) indicating the need for stronger antimicrobial stewardship to reduce the global threat of AMR. Prescribing of antibiotics in COVID-19 should be based on clinical and/or laboratory evidence of bacterial coinfection. Key strengths of this review, is that it included a comprehensive search strategy spanning over several databases, including both pre-prints and peer-reviewed studies. Limitations in this review was that during the screening process, a significant number of studies have been excluded due to not meeting the inclusion criteria, therefore, bacterial coinfection and antibiotic use may be under- or over-reported. In addition, disproportionate representation from North America and failure to include studies from regions other than Europe and Asia, can limit the generalizability of the results to other regions impacted by COVID-19References(1) Morris DE, Cleary DW, Clarke SC. Secondary bacterial infections associated with influenza pandemics. Front Microbiol. 2017;8:1041.(2) International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC). COVID-19 Clinical data report. 19May 2020.

Association of body mass index with COVID-19 related in-hospital death

BackgroundPatients with extreme body mass indices (BMI) could have an increased risk of death while hospitalized for COVID-19.MethodsThe database of the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) was used to assess the time to in-hospital death with competing-risks regression by sex and between the categories of BMI.ResultsData from 12,137 patients (age 60.0 ± 16.2 years, 59% males, BMI 29.4 ± 6.9 kg/m2) of 48 countries were available. By univariate analysis, underweight patients had a higher risk of mortality than the other patients (sub-hazard ratio (SHR) 1.75 [1.44–2.14]). Mortality was lower in normal (SHR 0.69 [0.58–0.85]), overweight (SHR 0.53 [0.43–0.65]) and obese (SHR 0.55 [0.44–0.67]) than in underweight patients. Multivariable analysis (adjusted for age, chronic pulmonary disease, malignant neoplasia, type 2 diabetes) confirmed that in-hospital mortality of underweight patients was higher than overweight patients (females: SHR 0.63 [0.45–0.88] and males: 0.69 [0.51–0.94]).ConclusionEven though these findings do not imply changes in the medical care of hospitalized patients, they support the use of BMI category for the stratification of patients enrolled in interventional studies where mortality is recorded as an outcome.

Liver injury in COVID-19: prevalence and association with patient-centered outcomes- an analysis of the international severe acute respiratory and emerging infection consortium (ISARIC) database

Background and Aim: Extrapulmonary manifestations are common in COVID-19 and elevations in components of liver function tests have been reported. Multiple mechanisms may contribute to these derangements. Using a large clinical dataset, we evaluated the prevalence and severity of derangements in liver function tests and their association with patient-centered outcomes. Methods: Using information available on the International Severe Acute Respiratory and emerging Infection Consortium database, we included patients with laboratory confirmed or suspected SARS-COV2 infection admitted to the hospital. The main exposure was the baseline liver function and main outcomes were hospital mortality, admission to an intensive care unit (ICU), receipt of oxygen therapy, non-invasive ventilation (NIV) or invasive ventilation, inotropes/vasopressors, renal replacement therapy, and the durations of hospital and ICU stay. We used generalized linear models to determine the association between exposure variables and outcomes. Results: From 708052 patients in the database, we included 17531 after excluding those with missing baseline information on liver function tests and outcomes. Nearly14% of patients had stage 2 liver injury at baseline and over 75% of the cohort had stage 3 liver injury. Stage 2 and 3 were associated with higher odds of mortality [ Stage 2- OR 1.82 (95%CI: 1.47-2.25) p value<0.001 and Stage 3- OR 1.50 (95%CI: 1.24-1.82) p value<0.001]. Stage 2 was also associated with higher odds of mechanical ventilation [ Stage 2- OR 1.6 (95%CI:1.34-2.06) p value<0.001] and a higher odds of ICU admission [ OR 1.13 (95%CI:0.95-1.35) p value=0.17]. For stage 3, this association with a higher probability of mechanical ventilation [OR 0.84 (95% CI:0.69-1.02) p value 0.08] and ICU admission [OR 0.24 (95% CI:0.21-0.28) p value<0.001)] was not observed. Conclusion: Liver function abnormalities are common among COVID-19 patients and are associated with worse clinical outcomes.