Laboratory-confirmed COVID-19 Cases Research Articles

Three-year Profile of COVID-19 Cases in Eastern Visayas, the Philippines (2020–2023)

This paper presents a three-year profile of laboratory-confirmed COVID-19 cases in Eastern Visayas, the Philippines, from 23 Mar 2020–31 Mar 2023 – with descriptive data on temporal trends, geographical variations, demographic factors, clinical characteristics, transmission patterns, and outcomes for vaccinated and unvaccinated cases. We analyzed data from the Regional Epidemiology and Surveillance Unit, Department of Health–Eastern Visayas Center for Health and Development to identify associations between COVID-19 severity and mortality and demographic and clinical factors. Moreover, we examined significant differences across gender cohorts and between vaccinated and unvaccinated individuals. During the three-year period, Eastern Visayas recorded 64,740 confirmed cases, with 98.93% recovery and 1.07% mortality. Most cases (61.72%) occurred in 2021 – with Tacloban, Ormoc, and Leyte having the highest attack rates per 100,000 population. Infections were asymptomatic (70.40%) or mild (21.83%), and 82.7% of deaths were linked to severe infections. Females accounted for 52.6% of the patients, with a lower mortality rate (44.5%) than males (55.5%). The 20–29 age group had the highest count (22.57%), whereas the 70–79 age group recorded the highest number of deaths (25.94%). The vast majority (93.6%) had no comorbidities. Comorbidities reported among deaths included kidney disease (11.3%), heart disease (7.6%), and hypertension (3.9%). Notably, no significant differences in recoveries and deaths were found between vaccinated and unvaccinated groups (p-value = 0.304). Logistic regression analysis showed that gender, age group, place of residence, comorbidity, and vaccination status were significantly associated with disease severity and mortality. Eastern Visayas demonstrated a relatively low COVID-19 caseload (1.59%) within the cumulative Philippine count. This is the most extensive COVID-19 case profile in the Philippines to date, hence providing essential data for pandemic preparedness, enhanced response strategies, and regional health crisis resilience.

Severe COVID-19 Outcomes in Five Latin American Countries in the Postvaccination Era.

We conducted a multicountry retrospective study using data from COVID-19 national surveillance databases to analyze clinical profiles, hospitalization rates, intensive care unit (ICU) admissions, utilization of ventilatory support, and mortality rates in five Latin American countries in the context of COVID-19 vaccination implementation. We analyzed the sociodemographic characteristics, comorbidities, clinical outcomes, and vaccination status of laboratory-confirmed COVID-19 cases from January 2021 to December 2022. We calculated the yearly and quarterly hospitalization rates per 1000 confirmed COVID-19 cases and ICU admissions, use of mechanical ventilators, and mortality rates per 1000 hospitalized cases, with their corresponding 95% confidence interval (CI) of 38,852,831 confirmed COVID-19 cases. Rates of hospitalization, ICU admission, ventilatory support, and death were higher among males than among females (38.2 vs. 32.4, 148.4 vs. 117.7, 282.9 vs. 236.2, and 346.9 vs. 320.1 per 1000, respectively); higher in 2021 than in 2022 (50.7 vs. 19.9, 207.8 vs. 58.2, 441.5 vs. 114.9, and 352.5 vs. 285.2 per 1000, respectively); and in the >50 age group (range: 5.7-18.6, 20.1-71.5, 12.2-67.9, and 353.1-577.4, per 1000) than the <50 age group (range: 2.2-9.3, 5.4-33.2, 41.4-135.8, and 22-243.5 per 1000). Hypertension and diabetes mellitus were the most common comorbidities in Mexico and Colombia. Prevention and treatment strategies for these case profiles could bring benefits from a public health perspective.

Association between meteorological variations and the superspreading potential of SARS-CoV-2 infections

BackgroundWhile many investigations examined the association between environmental covariates and COVID-19 incidence, none have examined their relationship with superspreading, a characteristic describing very few individuals disproportionally infecting a large number of people. MethodsContact tracing data of all the laboratory-confirmed COVID-19 cases in Hong Kong from February 16, 2020 to April 30, 2021 were used to form the infection clusters for estimating the time-varying dispersion parameter (kt), a measure of superspreading potential. Generalized additive models with identity link function were used to examine the association between negative-log kt (larger means higher superspreading potential) and the environmental covariates, adjusted with mobility metrics that account for the effect of social distancing measures. ResultsA total of 6,645 clusters covering 11,717 cases were reported over the study period. After centering at the median temperature, a lower ambient temperature at 10th percentile (18.2 °C) was significantly associated with a lower estimate of negative-log kt (adjusted expected change: −0.239 [95 % CI: −0.431 to −0.048]). While a U-shaped relationship between relative humidity and negative-log kt was observed, an inverted U-shaped relationship with actual vapour pressure was found. A higher total rainfall was significantly associated with lower estimates of negative-log kt. ConclusionsThis study demonstrated a link between meteorological factors and the superspreading potential of COVID-19. We speculated that cold weather and rainy days reduced the social activities of individuals minimizing the interaction with others and the risk of spreading the diseases in high-risk facilities or large clusters, while the extremities of relative humidity may favor the stability and survival of the SARS-CoV-2 virus.

Continued decline in the incidence of myocardial infarction beyond the COVID-19 pandemic: a nationwide study of the Swedish population aged 60 and older during 2015–2022

The number of myocardial infarctions declined during the early COVID-19 pandemic but mechanisms behind these declines are poorly understood. COVID-19 infection is also associated with an increased risk of myocardial infarction which could lead to higher incidence rates in the population. This study aims to shed light on the seemingly paradoxical relationship between COVID-19 and myocardial infarction occurrence on the population level by exploring long-term trends in incidence rates, case fatality, and proportion of patients dying before reaching a hospital. Our work is based on a linkage of administrative registers covering the entire population aged 60 + in Sweden. Considering both long-term trends since 2015 and seasonal variability, we compared observed incidence, case fatality, and proportions of patients hospitalized to expected values during 2020–2022. Despite more than 200 laboratory-confirmed COVID-19 cases per 1000 inhabitants by the end of 2022, incidence rates of myocardial infarction continued to decline, thus following the long-term trend observed already before 2020. During the first pandemic wave there was an additional incidence decline corresponding to 13% fewer myocardial infarctions than expected. This decline was neither accompanied by increasing case fatality nor by lower shares of patients being hospitalized. We found no increase in the population-level incidence of myocardial infarction despite large-scale exposure to COVID-19, which suggests that the effect of COVID-19 on myocardial infarction risk is not substantial. Increased pressure on the Swedish health care system has not led to increased risks or poorer outcomes for patients presenting with acute myocardial infarction.

Comparison of Neutralizing Activity between Vaccinated and Unvaccinated Hospitalized COVID-19 Patients Infected with Delta, Omicron BA.1, or Omicron BA.2 Variant.

Understanding the immune response to evolving viral strains is crucial for evidence-informed public health strategies. The main objective of this study is to assess the influence of vaccination on the neutralizing activity of SARS-CoV-2 delta and omicron infection against various SARS-CoV-2 variants. A total of 97 laboratory-confirmed COVID-19 cases were included. To assess the influence of vaccination on neutralizing activity, we measured the neutralizing activity of SARS-CoV-2 delta or omicron (BA.1 or BA.2) infection against wild-type (WT), delta, BA.1, and BA.2, with the results stratified based on vaccination status. The neutralizing activity against the WT, delta, and omicron variants (BA.1 and BA.2) was significantly higher in the vaccinated patients than those in the unvaccinated patients. In the unvaccinated individuals infected with the delta variant, the decrease in binding to BA.1 and BA.2 was statistically significant (3.9- and 2.7-fold, respectively) compared to the binding to delta. In contrast, vaccination followed by delta breakthrough infection improved the cross-neutralizing activity against omicron variants, with only 1.3- and 1.2-fold decreases in BA.1 and BA.2, respectively. Vaccination followed by infection improved cross-neutralizing activity against WT, delta, and BA.2 variants in patients infected with the BA.1 variant, compared to that in unvaccinated patients. Vaccination followed by delta or BA.1 infection is associated with improved cross-neutralizing activity against different SARS-CoV-2 variants. The enhanced protection provided by breakthrough infections could have practical implications for optimizing vaccination strategies.

The association of multiple sclerosis, traumatic brain injury, and spinal cord injury to acute and long COVID-19 outcomes.

Although persons with disabilities are a high-risk group, little is known about the association between specific disabling conditions and acute or long COVID outcomes. To examine the severity of acute SARS-CoV-2 infection and post-COVID outcomes among people with a preexisting diagnosis of multiple sclerosis (MS), spinal cord injury (SCI), or traumatic brain injury (TBI). This was a retrospective cohort study using the TrinetX Research Database, a large representative database of medical records. COVID-19-positive persons with MS, SCI, or TBI (cases) were matched 1:1 on age, gender, race, ethnicity, and comorbidities to COVID-19-positive persons without these diagnoses (controls). The main outcomes assessed were hospitalization for acute COVID-19, length of stay (LOS), the total number of hospitalizations, mortality, and incidence of six prevalent post-COVID sequelae within 6 months following a COVID-19 diagnosis. There were 388,297 laboratory-confirmed COVID-19 cases identified. Of these cases, 2204 individuals had one of the following preexisting diagnoses: 51.3% TBI, 31.4% MS, and 17.3% SCI. People with TBI, MS, and SCI were significantly more likely to be hospitalized for COVID-19 (odds ratio [OR] = 1.22, 95% confidence interval [CI] = 1.03-1.46) than matched controls. There was no difference in LOS, total hospitalizations, or mortality during the 6 months following the initial COVID diagnosis. Multivariable analyses reveal that persons with TBI, MS, and SCI were more likely to experience new weakness (OR = 1.54, 95% CI = 1.19-2.00), mobility difficulties (OR = 1.66, 95% CI = 1.17-2.35), and cognitive dysfunction (OR = 1.79, 95% CI = 1.38-2.33) than controls, even after controlling for the presence of these symptoms prior to their COVID infection and other risk factors. There were no differences in fatigue, pain, or dyspnea. Having a history of MS, SCI or TBI was not associated with higher mortality risk from COVID-19. However, associations between these diagnoses and postacute COVID-19 symptoms raise concern about widening health outcome disparities for individuals with such potentially disabling conditions following COVID-19 infection.

Evaluating completion rates of COVID-19 contact tracing surveys in New York City

ImportanceContact tracing is the process of identifying people who have recently been in contact with someone diagnosed with an infectious disease. During an outbreak, data collected from contact tracing can inform interventions to reduce the spread of infectious diseases. Understanding factors associated with completion rates of contact tracing surveys can help design improved interview protocols for ongoing and future programs.ObjectiveTo identify factors associated with completion rates of COVID-19 contact tracing surveys in New York City (NYC) and evaluate the utility of a predictive model to improve completion rates, we analyze laboratory-confirmed and probable COVID-19 cases and their self-reported contacts in NYC from October 1st 2020 to May 10th 2021.MethodsWe analyzed 742,807 case investigation calls made during the study period. Using a log-binomial regression model, we examined the impact of age, time of day of phone call, and zip code-level demographic and socioeconomic factors on interview completion rates. We further developed a random forest model to predict the best phone call time and performed a counterfactual analysis to evaluate the change of completion rates if the predicative model were used.ResultsThe percentage of contact tracing surveys that were completed was 79.4%, with substantial variations across ZIP code areas. Using a log-binomial regression model, we found that the age of index case (an individual who has tested positive through PCR or antigen testing and is thus subjected to a case investigation) had a significant effect on the completion of case investigation – compared with young adults (the reference group,24 years old < age < = 65 years old), the completion rate for seniors (age > 65 years old) were lower by 12.1% (95%CI: 11.1% – 13.3%), and the completion rate for youth group (age < = 24 years old) were lower by 1.6% (95%CI: 0.6% –2.6%). In addition, phone calls made from 6 to 9 pm had a 4.1% (95% CI: 1.8% – 6.3%) higher completion rate compared with the reference group of phone calls attempted from 12 and 3 pm. We further used a random forest algorithm to assess its potential utility for selecting the time of day of phone call. In counterfactual simulations, the overall completion rate in NYC was marginally improved by 1.2%; however, certain ZIP code areas had improvements up to 7.8%.ConclusionThese findings suggest that age and time of day of phone call were associated with completion rates of case investigations. It is possible to develop predictive models to estimate better phone call time for improving completion rates in certain communities.

Long-Term Kinetics of SARS-CoV-2 Neutralizing and Anti-Receptor Binding Domain Antibodies among Laboratory-Confirmed COVID-19 Cases in Delhi National Capital Region, India: A Prospective, One-Year Follow-Up Study.

Background: This study was conducted with the objective of measuring the neutralizing and anti-receptor binding domain antibody levels against SARS-CoV-2 among laboratory-confirmed COVID-19 cases and exploring its long-term kinetics over a period of 1 year. Methods: One hundred laboratory-confirmed COVID-19 cases were recruited. Serum samples of the participants were collected within three months from the date of the positive COVID-19 report. The participants were prospectively followed up every three months for symptoms and the collection of blood samples for three additional rounds. The presence of anti-SARS-CoV-2 antibodies (IgA, IgG, and IgM antibodies), anti-receptor binding domain antibodies (anti-RBD), and neutralizing antibodies were measured. Findings: Median plaque reduction neutralization test (PRNT) titers showed a rising trend in the first three rounds of follow-up. The quantitative anti-receptor binding domain ELISA (QRBD) values showed a declining trend in the initial three rounds. However, both the PRNT titers and QRBD values showed significantly higher values for the fourth round of follow-up. Total antibody (WANTAI) levels showed an increasing trend in the initial three rounds (statistically significant). Interpretation: Neutralizing antibodies showed an increasing trend. The anti-receptor binding domain antibodies showed a decreasing trend. Neutralizing antibodies and anti-RBD antibodies persisted in the majority.

Prespecified Homeopathic Medicines in the Prevention of Confirmed and Suspected Cases of COVID-19: A Community-Based, Double-Blind, Randomized, Placebo-Controlled Prophylaxis Trial

Introduction: Homeopathic medicines have been used for decades in the prevention and treatment of infectious diseases. However, the preventive efficacy of specific homeopathic medicines in COVID-19 is not well characterized. This study aimed to evaluate the comparative efficacy of prespecified homeopathic medicines in preventing COVID-19. Methods: A community-based, double-blind, randomized, placebo-controlled trial was conducted on 4,034 participants residing in Ward No. 27 of the Howrah Municipal Corporation in India. Participants were randomized to receive one of three prespecified homeopathic medicines [Influenzinum 30C, Arsenicum album 30C, Anas barbariae hepatis et cordis extractum 200K (Oscillococcinum®)], or placebo. The outcomes were the incidence of laboratory-confirmed and suspected cases of COVID-19 during a follow-up period of 1 month. Results: During the follow-up period, a total of 13 new laboratory-confirmed COVID-19 cases were reported in the study population. Among these, 5 cases in Influenzinum group, 2 cases in Arsenicum album group, 1 case in Oscillococcinum® group, and 5 cases in Placebo group were reported. On the other hand, number of suspected COVID-19 cases was significantly less in all the three homeopathic medicine groups compared to placebo. The least number of suspected cases reported in the Oscillococcinum® group (aOR: 0.058; 95% confidence interval [CI]: 0.029, 0.114), followed by the Arsenicum album (aOR: 0.337; 95% CI: 0.238, 0.475) and Influenzinum (aOR: 0.539; 95% CI: 0.401, 0.726) groups. Conclusion: Prespecified homeopathic medicines, particularly Oscillococcinum® and Arsenicum album 30C, may have a role in preventing COVID-19, especially in reducing the incidence of suspected or COVID-19-like respiratory illnesses. However, the result failed to demonstrate a statistically significant difference in the occurrence of confirmed cases of COVID-19 between the study groups. Further research is needed to evaluate the efficacy of these medicines in different populations and settings.

SARS-CoV-2 infection and seropositivity among household contacts of laboratory confirmed cases of COVID-19 in residents of Delhi, India

The transmission of respiratory pathogens, including SARS-CoV-2, is often facilitated through household contact. To better understand the transmission rate of COVID-19 among households and factors that affect viral clearance and seroconversion, a case-ascertained community-based prospective study was conducted between December 2020 and June 2021 on the urban population of the national capital region of India. The study collected nasopharyngeal swabs for SARS-CoV-2 RT-PCR on the 1st, 7th, 14th, and 28th day, and blood samples for antibody detection on the 1st, 14th, and 28th day from household contacts (HCs) of laboratory-confirmed COVID-19 cases. The study monitored the demographic data, symptoms, and outcomes of 417 participants, including 99 index cases and 318 contacts, for a period of 28 days. The results of the study showed that SARS-CoV-2 was easily spread within households, with a secondary infection rate of 44.3 %. In fact, almost 70 % of the contacts got infected within 1–2 days of identification of the index case, while 34 % remained asymptomatic. Sero-conversion was found in 35.6 % of the participants while 22.9 % did not produce antibodies after 28 days of infection. The study also revealed that females, spouses, older members, and primary care providers were at higher risk of getting infected in a home setting. However, approximately one-third of individuals in the younger age group managed to avoid infection. The study demonstrated that most infected individuals became RT-PCR negative within two weeks, although viral clearance was delayed in older patients and those with lower cycle threshold values in RT-PCR.

Monitoring COVID-19 in Belgian general practice: A tool for syndromic surveillance based on electronic health records.

COVID-19 may initially manifest as flu-like symptoms. As such, general practitioners (GPs) will likely to play an important role in monitoring the pandemic through syndromic surveillance. To present a COVID-19 syndromic surveillance tool in Belgian general practices. We performed a nationwide observational prospective study in Belgian general practices. The surveillance tool extracted the daily entries of diagnostic codes for COVID-19 and associated conditions (suspected or confirmed COVID-19, acute respiratory infection and influenza-like illness) from electronic medical records. We calculated the 7-day rolling average for these diagnoses and compared them with data from two other Belgian population-based sources (laboratory-confirmed new COVID-19 cases and hospital admissions for COVID-19), using time series analysis. We also collected data from users and stakeholders about the syndromic surveillance tool and performed a thematic analysis. 4773 out of 11,935 practising GPs in Belgium participated in the study. The curve of contacts for suspected COVID-19 followed a similar trend compared with the curves of the official data sources: laboratory-confirmed COVID-19 cases and hospital admissions but with a 10-day delay for the latter. Data were quickly available and useful for decision making, but some technical and methodological components can be improved, such as a greater standardisation between EMR software developers. The syndromic surveillance tool for COVID-19 in primary care provides rapidly available data useful in all phases of the COVID-19 pandemic to support data-driven decision-making. Potential enhancements were identified for a prospective surveillance tool.

SARS-CoV-2 rapid antigen testing positive rate in community testing stations as an indicator for COVID-19 epidemic trend, Taipei, Taiwan, May to August 2021

BackgroundReal-time surveillance of COVID-19 in large-scale community outbreaks presents challenges. Simple counts of the daily confirmed cases can be misleading due to constraints from bottlenecks in access to care or laboratory testing. This study aimed to investigate the role of the SARS-CoV-2 antigen rapid diagnostic test (Ag-RDT) in addressing these challenges for real-time COVID-19 surveillance. MethodsThis study included the results of 86,933 SARS-CoV-2 Ag-RDT and real-time reverse transcription polymerase chain reaction (RT-PCR) tests. These were conducted at four community testing stations within the Taipei metropolitan area during a community COVID-19 outbreak spanning from May 17, 2021, to August 9, 2021. We examined the correlation between the positive rates of Ag-RDT tests and the epidemic curve of laboratory-confirmed COVID-19 cases by onset date to examine its role in real-time surveillance. ResultsDuring the 85-day study period, the trend of Ag-RDT test positive rates paralleled that of the epidemic curve. The correlation between the Ag-RDT positive rate and the number of cases (Pearson correlation coefficient: 0.968) is comparable to that of the RT-PCR positive rate (Pearson correlation coefficient: 0.964). The Ag-RDT positive rate exhibited a more advanced leading trend, with Ag-RDT leading by 3 days in comparison to the 2-day lead for RT-PCR. ConclusionThe positive rate of SARS-CoV-2 Ag-RDT tests at community testing stations serves as a good surrogate for assessing virus activity within the community and a useful tool for real-time COVID-19 surveillance. It is a robust indicator of the outbreak trend and near-term numbers of cases. This finding may facilitate the management of subsequent outbreaks of emerging infectious diseases.

Transmissibility and severity of COVID-19 in a humanitarian setting: First few X investigation of cases and contacts in Juba, South Sudan, 2020.

The first few 'X' (FFX) studies provide evidence to guide public health decision-making and resource allocation. The adapted WHO Unity FFX protocol for COVID-19 was implemented to gain an understanding of the clinical, epidemiological, virological and household transmission dynamics of the first cases of COVID-19 infection detected in Juba, South Sudan. Laboratory-confirmed COVID-19 cases were identified through the national surveillance system, and an initial visit was conducted with eligible cases to identify all close contacts. Consenting cases and close contacts were enrolled between June 2020 and December 2020. Demographic, clinical information and biological samples were taken at enrollment and 14-21 days post-enrollment for all participants. Twenty-nine primary cases and 82 contacts were included in the analyses. Most primary cases (n= 23/29, 79.3%) and contacts (n= 61/82, 74.4%) were male. Many primary cases (n= 18/29, 62.1%) and contacts (n= 51/82, 62.2%) were seropositive for SARS-CoV-2 at baseline. The secondary attack rate among susceptible contacts was 12.9% (4/31; 95% CI: 4.9%-29.7%). All secondary cases and most (72%) primary cases were asymptomatic. Reported symptoms included coughing (n= 6/29, 20.7%), fever or history of fever (n= 4/29, 13.8%), headache (n= 3/29, 10.3%) and shortness of breath (n= 3/29, 10.3%). Of 38 cases, two were hospitalised (5.3%) and one died (2.6%). These findings were used to develop the South Sudanese Ministry of Health surveillance and contract tracing protocols, informing local COVID-19 case definitions, follow-up protocols and data management systems. This investigation demonstrates that rapid FFX implementation is critical in understanding the emerging disease and informing response priorities.

Heterologous booster vaccines reduce severity and mortality in COVID-19 during BA.2 and BA.4/BA.5 omicron predominance in Thailand

BackgroundThe COVID-19 pandemic has evolved quickly, with variants of concern resulting in the need to offer booster vaccinations. Unfortunately, the booster uptake has been slow and vaccine response has shown to wane over time. Therefore, it's critical to evaluate the role of vaccinations on outcomes with newer sub-lineages of omicron. MethodsUtilising a Hospital Information System established in Chiang Mai, Thailand, we conducted a cohort study by linking patient-level data of laboratory-confirmed COVID-19 cases to the national immunization records, during BA.2 and BA.4/BA.5 predominance. ResultsIn adjusted cox-proportional hazard models, BA.4/BA.5 was not associated with more severe COVID-19 outcomes or deaths as compared to BA.2. Risk of severe outcomes and deaths were significantly reduced with third (87% and 95%) and fourth (88% and 95%) dose vaccination, while events were not observed with a fifth dose. Across the regimens, vaccination within 14–90 days prior showed the highest level of protection. All the vaccine types used for boosting in Thailand offered similar protection against severe COVID-19. ConclusionsBoosters provide high level of protection against severe COVID-19 outcomes and deaths with newer omicron sub-lineages. Booster campaigns should focus on improving coverage utilising all available vaccines to ensure optimal protection.

Endemic characteristics of SARS-CoV-2 infection

The fourth year of the COVID-19 pandemic without decreasing trends in the global numbers of new daily cases, high numbers of circulating SARS-CoV-2 variants and re-infections together with pessimistic predictions for the Omicron wave duration force studies about the endemic stage of the disease. The global trends were illustrated with the use the accumulated numbers of laboratory-confirmed COVID-19 cases and deaths, the percentages of fully vaccinated people and boosters (additional vaccinations), and the results of calculation of the effective reproduction number provided by Johns Hopkins University. A new modified SIR model with re-infections was proposed and analyzed. The estimated parameters of equilibrium show that the global numbers of new daily cases will range between 300 thousand and one million, daily deaths—between one and 3.3 thousand.

The Burden and Characteristics of Post-COVID-19 Conditions Among Laboratory-Confirmed Delta and Omicron COVID-19 Cases: A Preliminary Study From Maharashtra, India.

Post-COVID-19 conditions (PCC) have emerged as a significant global health concern due to their potential impact on patients' quality of life and healthcare resources. The present study aims to understand the burden and characteristics of PCC in Maharashtra, India, and compares its prevalence among cases infected with Delta and Omicron variants. A retrospective observational study included 617 laboratory-confirmed Delta and Omicron variant cases. These cases were telephonically followed up to document persistent COVID-19 symptoms using a questionnaire based on the Post-COVID-19 Clinical Form from the Global COVID-19 Clinical Platform of the World Health Organization (WHO), and the results were analyzed. Out of 617 laboratory-confirmed COVID-19 cases, 82.97% and 17.03% were Omicron and Delta cases, respectively. The mean follow-up period for Delta and Omicron cases was 78.05 and 21.56 weeks, respectively. A total of 40 (6.48%) cases reported persistent symptoms at follow-up, with a higher prevalence among those infected with the Delta variant (12.38%) compared to the Omicron variant (5.27%). The most common long COVID symptoms reported were malaise (25%), dyspnea (20%), post-exertional fatigue (17.5%), joint pain (15%), and frequent episodes of cough and cold (15%). Additionally, 1.94% of participants developed a new medical condition following COVID-19 infection, most commonly hypertension (25%), lung fibrosis (16.67%), and asthma (8.33%). Factorssuch as more than five acute symptoms, amoderate to severe disease, the need for hospitalization, and hospitalization for more than five days were significantly associated with PCC. Long COVID results in extended disability and illness. The varying impacts of different COVID-19 variants highlight the complex nature of post-COVID-19 complications. Our findings highlight the need for strategic planning of healthcare resources to ensure optimal response and preparedness to manage the burden of PCC.

Effectiveness of BNT162b2 and Sinovac vaccines against the transmission of SARS-CoV-2 during Omicron-predominance in Hong Kong: A retrospective cohort study of COVID-19 cases.

In 2022, SARS-CoV-2 Omicron variants circulated globally, generating concerns about increased transmissibility and immune escape. Hong Kong, having an infection-naive population with a moderate 2-dose vaccine coverage (63% by the end of 2021), experienced a COVID-19 epidemic largely seeded by Omicron BA.2 variants that led to the greatest outbreak in the region to date. Little remains known about the protection of commonly-administered vaccines against transmission of Omicron BA.2 variants. In this retrospective cohort study, we identified 17 535 laboratory-confirmed COVID-19 cases using contact tracing information during the Omicron-predominant period between January and June 2022 in Hong Kong. Demographic characteristics, time from positive test result to case reporting, isolation, or hospital admission, as well as contact tracing history and contact setting were extracted. Transmission pairs were reconstructed through suspected epidemiological links according to contact tracing history, and the number of secondary cases was determined for each index case as a measurement for risk of transmission. The effectiveness of mRNA vaccine (BNT162b2) and inactivated vaccine (Sinovac) against transmission of BA.2 variants was estimated using zero-inflated negative binomial regression models. Vaccine effectiveness against transmission for patients who received the 2-dose BNT162b2 vaccine was estimated at 56.2% (95% CI: 14.5, 77.6), 30.6% (95% CI: 13.0, 44.6), and 21.3% (95% CI: 2.9, 36.2) on 15 - 90, 91 - 180, and 181 - 270 days after vaccination, respectively, showing a significant decrease over time. For 3-dose vaccines, vaccine effectiveness estimates were 41.0% (95% CI: 11.3, 60.7) and 41.9% (95% CI: 6.1, 64.0) on 15 - 180 days after booster doses of Sinovac and BNT162b2, respectively. Although significant vaccine effectiveness was detected in household settings, no evidence of such protective association was detected in non-household settings for either Sinovac or BNT162b2. Moderate and significant protection against Omicron BA.2 variants' transmission was found for 2 and 3 doses of Sinovac or BNT162b2 vaccines. Although protection by 2-dose BNT162b2 may evidently wane with time, protection could be restored by the booster dose. Here, we highlight the importance of continuously evaluating vaccine effectiveness against transmission for emerging SARS-CoV-2 variants.

Factors Related to the Transmission of COVID-19 within Households from Pediatric Initial Cases

Objectives: This study aims to identify pediatric COVID-19 transmission the general and epidemiological characteristics within households and determine odds ratios (OR) of transmission based on these characteristics. Methods: This study analyzed all laboratory-confirmed (PCR +) initial pediatric COVID-19 cases aged 0 to 18 years reported in Daegu, Republic of Korea, between February 18, 2020, and December 31, 2021 (n = 1,348). Household transmission was defined as households where at least one secondary case occurs within 1 to 14 days after the pediatric initial case. The study excluded cases that were known as the index case in the household but were identified as a secondary case through epidemiological investigation. Additionally, if the source of infection was unknown, they were excluded, provided at least one family member confirmed positive on the laboratory-contact test, including cases with incomplete epidemiological investigation. Results: 469 cases (34.8%) experienced household transmission. Male, symptomatic and cases with unknown source of infection had higher OR of transmitting COVID-19 to the household compared to the opposite scenarios (Male: OR, 1.36; 95% CI, 1.07-1.74; Symptomatic: OR, 1.93; 95% CI, 1.36-2.73; unknown source of infection: OR, 2.26; 95% CI, 1.59-3.21). Moreover, the age group of 4-6 years had the highest OR of transmitting COVID-19 to household contacts compared to the age group of 13-18 years (OR, 3.59; 95% CI, 2.55-5.05), and the age groups of 7-12 years (OR, 2.62; 95% CI, 1.94-3.53) and 0-3 years (OR, 2.25; 95% CI, 1.22-4.15) also showed higher ORs. However, the OR for the Ct value was 0.98 (95% CI, 0.96-0.99). Conclusions: This study suggests that male, symptomatic and cases with unknown sources in pediatric COVID-19 patients are more likely to transmit COVID-19 within households. Younger pediatric patients have higher OR for COVID-19 households transmission than older ones. However, the high Ct value indicated a lower likelihood of transmission.

Utility of baseline D-dimer and neutrophil-to-lymphocyte ratio (NLR) in predicting the severity among COVID-19 patients in an Indian cohort during the first wave of the pandemic

Introduction and Aim: COVID-19 outbreak was declared as pandemic by WHO Director-General on 11th March 2020 in his opening remarks at the media briefing. The global population infected by Corona virus appeared to be responding at different levels in the first wave which warranted WHO to categorise the disease as mild, moderate, and severe. Haematological, biochemical, and radiological parameters played a crucial role in critically triaging and following-up disease progression. Amongst various laboratory parameters, this work aimed to identify the most specific marker in predicting disease severity. Materials and Methods: Blood samples from study population of 510 laboratory confirmed COVID-19 cases admitted in our hospital were selected. The patients who were classified as having mild, moderate, and severe disease were analysed for biochemical and haematological inflammatory markers. Results were analysed by ANOVA and post-hoc tests. ROC curves were derived to determine the cut-off values between severe and non-severe groups. Correlation between D-dimer and NLR was done by Pearson’s correlation. Results: Patients with co-morbidities were likely to develop severe complications which could lead to poor outcome. From ROC curves, we determine that NLR, with highest area under curve, is the best marker of disease severity. A significant positive correlation was found between D-dimer and NLR (p=0.000) across groups. Baseline cut-off values for D-dimer and NLR based to differentiate between severe and non-severe cases were 0.5 and 4.875 respectively. Conclusion: We conclude that baseline NLR is a simple and most useful tool that would assist clinicians in designing treatment strategies for a COVID-19 infected patient.

A Retrospective Study on Smell Dysfunction in COVID-19 Patients Presenting to a Tertiary Care Teaching Hospital in Northern India

Introduction: The smell dysfunction in COVID-19 patients has remained an unexplained topic. The blood parameters’ variability in COVID-19 patients with anosmia has been studied in few literatures. The study is aimed to find the association of anosmia with the blood grouping and C-reactive protein (CRP) levels in coronavirus-infected patients. Materials and Methods: Database from Medical Records Department of a Tertiary Care Teaching Hospital in Northern India was searched from July 2020 to December 2020. Every fifth file was selected using the stratified random sampling. Laboratory-confirmed COVID-19 cases by reverse transcription-polymerase chain reaction files were included. Blood grouping and CRP levels were assessed and statistically correlated. Results: A total of 103 patients of coronavirus-associated infection with anosmia were included among which 52 (50.48%) patients were from moderate category of AIIMS-ICMR joint task Force’s clinical guidelines. A total of 44 (42.71%) patients had moderate levels of elevated CRP. The blood Group B-type was found most commonly in 35 (33.98%) patients. The correlation of severity of COVID-19 infection with CRP was found to be statistically significant (Chi-square test statistic was 31.203 and P = 0.00023) in patients presenting with smell dysfunction. Conclusion: Anosmia was found to a suggestive symptom for the early identification of coronavirus-infected cases. In this study, CRP levels showed statistically significant association with anosmia in COVID-19 patients. Predilection for specific blood groups serves as platform for further research.