PCR Positivity Rates Research Articles

The Epidemiological Pattern and Co-infection of Influenza A and B by Surveillance Network From 2009 to 2014 in Anhui Province, China.

Influenza-like illness (ILI) is one of the most important public health problems globally, causing an enormous disease burden. Influenza infections are the most common cause of ILI. Bacterial and virus co-infection is common yet the data of co-infection with influenza A and B viruses are scarce. To identify the epidemiological patterns of and co-infection of influenza A and B in Anhui province, China, we analyzed the surveillance data of 5 years from 2009 to 2014 collected by the Chinese National influenzas network. The results showed that the weekly ratio of ILI was 3.96 ± 1.9% (95% CI 3.73–4.2%) in outpatients and the highest affected population was children under 5 years old. The epidemic of influenza viruses was highest during 2009–2010. For the other 4 surveillance years, school-aged people (5–14 years) were the most highly affected population. Influenza B and H3N2 viruses were more prevalent than H1N1pdm09 virus after 2010. In addition, a significant co-circulation of influenza A (H1N1pdm09 and H3N2) and influenza B virus was detected with 0.057% PCR positive rate during 2009–2014 in Eastern China, yet isolated only in pediatric patients. Our data reveals school-aged population would be the main vulnerable population and a distinct seasonality for influenza. In addition, the co-infection of influenza A and B were found in Anhui Province, China. Ongoing surveillance is critical to understand the seasonality variation and make evidence-based vaccination recommendations. Information on the epidemiological patterns and co-infections of influenza A and B can help us to implement different strategies for selecting vaccine formulations and monitoring new emerging influenza strains. In addition, the identification of the susceptible population can help us to develop more precise protection measures.

SARS-CoV-2 viral load dynamics and real-time RT-PCR cycle threshold interpretation in symptomatic non-hospitalised individuals in New Zealand: A multicentre cross-sectional observational study

Aims: To describe population-level SARS-CoV-2 upper respiratory tract (URT) viral load dynamics by stratifying PCR positivity rates and Ct values by days since symptom onset (DSSO), and to explore utility of Ct values in determining infectivity.

Do children with severe acute respiratory infection need cohorting & isolation before screening for COVID-19?

This retrospective analysis was done to ascertain the SARS-CoV-2-positivity rate in children (0-12 yr) with severe acute respiratory infection (SARI) and compare it to those without SARI to determine the need for running a dedicated SARI isolation facility for paediatric COVID-19 care. The case records of 8780 children (0-12 yr) admitted and/or tested for SARS-CoV-2 between June 2020 and May 2021 at a tertiary care centre in north India were analyzed. The overall SARS-CoV-2 reverse transcription (RT)-PCR positivity rate was 3.0 per cent (262/8780). There were 1155 (13.15%) children with SARI. Fifty of these 1155 (4.3%) children with SARI, as against 212 of the 7625 (2.8%) children without SARI, tested positive for COVID-19. The absolute difference in the positivity rate among SARI and non-SARI groups was only 1.54 per cent which translates to cohorting and isolating 65 children with SARI to pick up one extra SARS-CoV-2-positive child (compared to those without SARI). The positive predictive value of SARI as a screening test was 4.3 per cent. Our findings suggest that isolation of children with SARI as a transmission-prevention strategy for COVID-19 may not be required. This is particularly relevant in resource-limited settings.

Ambulatory Cholecystectomy in the COVID-19 Era: Safety of a Major Outpatient Surgery Program in Pandemic

Since the Coronavirus disease 2019 (COVID-19) pandemic, elective surgery decreased substantially. On the other hand, a delay in the treatment of cholelithiasis in Chile leads to a significant morbidity, making surgical intervention essential. In this scenario, we performed the present study with the aim of defining if a major ambulatory surgery program is safe in the COVID-19 era. We included patients operated of ambulatory laparoscopic cholecystectomy between August 2020 and February 2021 in a hospital center in Santiago de Chile, during the peak of the COVID-19 pandemic, with an average PCR positivity rate of 6% and an ICU bed occupancy rate >80% in that period. Prospective data were collected to include baseline demographics, operative procedure and 30-day post-operative outcomes. A total of 109 cholecystectomies were performed, with a majority ASA I-II (American Society of Anaesthesiologists), in patients with cholelithiasis. 98.2% were completed laparoscopically, with a 17,4% rate for vesicular perforation. Thirty day follow-up revealed a complication rate of 44%, with 16,5% of patient having diarrhea and 17,4% abdominal pain. Only 2 patients (1.8%) developed COVID-19 symptoms postoperatively. 15.6% of patients attended the emergency department in the 30-day postoperative period. Early discharge was feasible in all patients. Our study demonstrates that an ambulatory cholecystectomy program during the COVID-19 pandemic can be carried out safely and effectively. Complications evidenced are in agreement with the reported literature, with a caveat of careful patient selection. We demonstrated that ambulatory surgery is feasible during pandemic, with a low incidence of COVID-19 infection, and without mortality.

385. SARS-CoV-2 Infections Among Military Personnel Deployed on the USNS COMFORT to New York City During the COVID-19 Pandemic and One-Year Follow-Up

BackgroundThe USNS COMFORT deployed to New York City to augment the inpatient health care capacity in March 2020. The aim of this study was to determine the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection among US Navy personnel upon return from deployment, and to identify incident cases of SARS-CoV-2 infection during 1 year of follow-up.MethodsCrewmembers, the majority of whom were health care workers (HCW), were enrolled following deployment, in May 2020. PCR results from symptomatic crewmembers during deployment, and Day 0 and Day 14 post-deployment screening swabs conducted on all crewmembers, per military order, were abstracted. A questionnaire and serum were collected on Day 14 post-deployment. SARS-CoV-2 infection was defined as a positive SARS-CoV-2 spike glycoprotein immunoglobulin G antibody (IgG) or PCR. COVID-19 related medical encounters, PCR and antibody testing results within 1 year following deployment were abstracted from the Military Health System Data Repository (MDR). There was adequate provision of personal protective equipment (PPE) in the hospital and the COVID-19 vaccine roll-out for HCW began in December 2020. ResultsOf the 1200 crewmembers, 449 were enrolled and completed the questionnaire and screening swabs, and 432 (96.2%) completed the Day 14 blood draw (Table 1). The cumulative prevalence of SARS-CoV-2 infection was 3.01% (13/432; 95% CI, 1.61%–5.09%). One of 17 subjects did not complete the blood draw and was PCR positive on Day 14. 433/449 (96.4%) had a PCR performed during the follow-up period (i.e. after the Day 14 post-deployment visit until Feb 2021), for HCW screening or symptomatic illness (median number of tests: 2 [IQR: 1, 2; range: 1,6]). 25 of 433 (5.8%) were PCR positive (Fig 1). 19 (76.0%) occurred in corpsmen, 23 (92.0%) were symptomatic and none were hospitalized. One asymptomatic re-infection occurred in a crewmember who was PCR negative and IgG positive at Day 14 post-deployment. Table 1. Characteristics of the overall cohort and by SARS-CoV-2 infection Figure 1. Number of PCR tests (bar graph) and positivity rate (red line) by month in 449 USNS COMFORT crewmembers during 1-year follow-up after return from deployment ConclusionThe post-deployment prevalence of SARS-CoV-2 infection was low. A high proportion of HCW underwent PCR testing during 1-year follow-up but a low incidence of infection was observed. This was likely from community transmission as nosocomial transmission was mitigated by adequate PPE and vaccine roll-out. Disclosures All Authors: No reported disclosures

First cases of Mycobacterium leprae (Hansen’s disease) detection in Côte d’Ivoire using molecular diagnosis (PCR)

Background Leprosy is a skin disease caused by Mycobacterium leprae. It is the second mycobacterial disease after tuberculosis still presenting a public health problem in many countries today. With the advent of multidrug therapy in 1982, much progress has been made in the fight against this disease, which causes severe social consequences. Côte d’Ivoire, like many African countries, reached the elimination threshold of disease and MDT is available throughout the country. However, Côte d’Ivoire has not managed to break the chain of transmission of M. leprae. Thus, in the country where leprosy is endemic, the number of Grade II disabilities observed remains significant. Methods and results The diagnosis of infection is often made by default, based only on clinical and microscopic evidence; we are committed to implementing PCR, a previously unavailable diagnostic tool, to help confirm suspected leprosy cases. Samples consisting of nasal mucus and slits skin smears were collected from 39 suspect cases for confirmation by PCR. DNA was extracted and amplified, targeting M. leprae repeated elements (RLEP). Results showed a PCR positivity rate of 38.5%. PCR products of the repetitive elements were sequenced and BLASTn analysis confirmed that the amplified products obtained were part of the M. leprae genome. PCR is now available for confirmation of leprosy cases in Côte d’Ivoire. This will help to reduce the consequences of leprosy and promote its elimination.

Seroprevalence of SARS-CoV-2 Infection in the Colombo Municipality Region, Sri Lanka.

Background: As the Municipality Council area in Colombo (CMC) experienced the highest number of cases until the end of January 2021, in Sri Lanka, we carried out a serosurvey prior to initiation of the vaccination program to understand the extent of the SARS-CoV-2 outbreak.Methods: SARS-CoV-2 seropositivity was determined in 2,547 individuals between the ages of 10–86 years, by the Wantai total antibody ELISA. We also compared seroprevalence using the haemagglutination test (HAT) to evaluate its usefulness in carrying out serosurveys.Results: The overall seropositivity rate was 24.46%, while seropositivity by HAT was 18.90%. Although The SARS-CoV-2 infection detection rates by PCR were highest in the population between the ages of 20–60 years of age, there was no statistically significant difference in the seropositivity rates in different age groups. For instance, although the seropositivity rate was highest in the 10–20 age group (34.03%), the PCR positivity rate was 9.80%. Differences in the PCR positivity rates and seropositivity rates were also seen in 60–70-year-olds (8.90 vs. 30.4%) and in individuals >70 years (4.10 vs. 1.20%). The seropositivity rate of the females was 29.70% (290/976), which was significantly higher (p < 0.002) than in males 21.2% (333/1,571).Conclusions: A high seroprevalence rate (24.5%) was seen in all age groups in the CMC suggesting that a high level of transmission was seen during this time. The higher PCR positivity rates between the ages of 20–60 are likely to be due to increased testing carried out in the working population. Therefore, the PCR positivity rates, appear to underestimate the true extent of the outbreak and the age groups which were infected.

COVID-19 seroconversion in the aircrew from Turkey

BackgroundPneumonia due to Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) is spreading rapidly all over the world and air travel is the leading transmission route of the virus among countries. The aim of the study is to determine the frequency of SARS-CoV-2 Immunoglobulin G (IgG) antibodies in aircrew, to determine occupational exposure, and to understand the spread of immunity in social groups. MethodThe study was designed as a cross-sectional retrospective study. SARS-CoV-2 IgG levels were measured in patients who applied to between December 1, 2020 and January 13, 2021. Coronavirus disease-2019 (COVID-19) Reverse transcription polymerase chain reaction (RT-PCR) positivity was investigated before December 1, 2020. ResultsThe patients were divided into three groups according to their jobs such as 313 aircrew; 451 healthcare workers; 4258 other patients. The PCR positivity rate was found to be 39% in the aircrew group, 32% in the healthcare workers and %20 other patient group (p < 0.001). The IgG antibody positivity rate was 46% in the aircrew, 41% in healthcare workers, and 35.3% in the other patient group (p < 0.001).The group with the highest IgG antibody titer is in the aircrew; there was a significant difference between the groups (p < 0.001). ConclusionsIn our study, it was observed that aircrew, similar to healthcare workers, are at serious risk against SARS-CoV-2. In this process, it is suggested that the vaccination processes included repeated doses of aircrew should be accelerated and protective measures and equipment should be increased in terms of reinfection.

A retrospective analysis of 902 hospitalized COVID‐19 patients in Lebanon: clinical epidemiology and risk factors

Background: The clinical epidemiology of hospitalized COVID-19 patients has never been described before in Lebanon. Moreover, the hospital admission and PCR positivity rates have not been assessed and compared yet. Objectives: To describe the characteristics and outcomes of hospitalized patients with coronavirus induced disease 2019 (COVID-19) in Lebanon and identify risk factors for severe disease or death. Study design: This is a retrospective mono-center cohort study in which we used patients’ files to extract and analyse data on demographic and clinical characteristics, as well as mortality. Moreover, we tracked the pandemic by recording the daily total and ICU inpatient census and the PCR positivity rate for admitted and outpatients. Results: Although the total admission rate increased from September to April, the ICU census switched this trend in December to stabilize at an average of around 10 patients/day until April. The case fatality rate was 19% for the 902 hospitalized patients, of which the majority (80%) had severe COVID-19. The severity odds ratio is significantly decreased in immunosuppressed cases (OR, 0.18; CI, 0.05-0.67; p=0.011). Additionally, the odds of COVID-19 related death are significantly greater if consolidations are found in the chest computed tomography (CT) scan (OR, 12; CI, 2.63-55.08; p=0.0013). Conclusion: Consolidations in the lungs significantly increase the COVID-19 death risk. Risk factors identification is important to improve patients’ management and vaccination strategies. In addition, hospital statistics are good indicators of a pandemic's track.

Serologic and Molecular Detection of Mycoplasma gallisepticum in Layer Flocks in South Marmara Region of Turkey

Background: Due to the economic impacts of Mycoplasma gallisepticum (MG) infection in poultry, it is essential to have a fast, reliable and accurate diagnostic test to diagnose the infection.&#x0D; Aims: It was aimed to examine the presence of MG in the South Marmara Region of Turkey where extensive commercial layer flocks exist by RPA, ELISA and real-time PCR.&#x0D; Materials and Methods: In the study, 981 sera and 160 tracheal swab samples (20 swabs per each flock) obtained from eight layer flocks were examined for the presence of MG-antibody by RPA, ELISA, and the presence of MG by real-time PCR, respectively.&#x0D; Results: MG-seropositive flock rate was determined to be 100% by RPA. Twenty-three of the RPA positive sera in each flock LA, LB, LC, LD, LF, LG, and 17 RPA positive sera in flock LE (due to 17 positive RPA sera obtained) were examined for the presence of MG antibody by ELISA, and MG-seropositive flock rate was determined to be 87.5%. As a result of the examination of a total of 32 tracheal swab samples (20 swabs perflock/5 swabs=4 pooled samples, 8 flocksX4 pooled samples= 32 samples) for the presence of MG, real-time PCR positive flock rate was found to be 75%.&#x0D; Conclusion: To decide the flock whether it is infected or not and the initiate effective preventive measures against MG infection as soon as possible; serology should be applied simultaneously with bacteriology and/or PCR to prevent time loss due to shortcomings of serological tests used as primary screening test such as cross reactions, sensitivity and specificity problems.

Assessment of COVID-19 Contact Healthcare Workers at Manisa Celal Bayar University Hospital

Introduction: In the COVID-19 pandemic process, the health of healthcare workers with a high risk of infection is critical. Many healthcare workers have become infected while serving COVID-19 patients, and they have also been and are still exposed to the disease agent at hospital, household or community-based. The aim of this study was to determine the risk status of healthcare workers in contact with COVID-19 patients working at Manisa Celal Bayar University Hospital, and to reveal COVID-19 surveillance and related results. Materials and Methods: This descriptive study was based on examining the data of healthcare workers (HW) that came in contact with the disease between 1 April and 31 December 2020 to the COVID-19 Surveillance Unit (SU), which was established by Manisa Celal Bayar University Public Health Department during the pandemic process. Results: Among the in-contact health workers;65.7% were females, 42.5% were nurses and 26.0% were physicians. 23.8% of the contacts were high, 42.9% medium and 33.3% low risk. High risk contact percanteges were statistically higher in the emergency unit personal, laboratory workers and household/community based contacts (p= 0.000). PCR positivity rate was 10.1% in high risk contact and 3.6% in medium risk contact (p= 0.000). During the research period, the rate of COVID-19 positivity in healthcare workers at Manisa Celal Bayar University Hospital was determined as 21.9% (n= 374). In the study, 24.9% of COVID-19 positive healthcare workers were physicians and 29.0 % were nurses. Conclusion: 23.8% of HCW were evaluated as high risk contact and 21.9% of the group tested positive. High risk contact percanteges were statistically higher in the emergency unit personal, laboratory workers and household/community based contacts. Protecting healthcare workers from infection in the fight against pandemics and performing contact follow-ups are also vital for continuity of service.

Should Elective Surgical Procedures Be Delayed in Pediatric Cases in Covid-19 Pandemic? Until When? Is Pcr Required in The Preoperative Period?

Objective : The COVID-19 pandemic has led to major changes in healthcare around the world, including postponing elective surgery. The aim of this study is to examine the COVID-19 test results in pediatric patients who are asymptomatic and have no history of contact with a COVID-19 case prior to their scheduled elective surgery. Material and Methods: This prospective study has evaluated pediatric patients who were asymptomatic and had no contact history with a COVID-19 case and who were scheduled for elective surgery between 01.05.2020-31.10.2020 in one of the world’s largest pediatric hospitals. Nasopharyngeal swab (PCR) samples were obtained from all patients one day before the scheduled elective surgery. Results: Eight hundred twelve patients in this study had a mean age of 6.98 ± 4.37 years. The PCR test was positive in 4 patients (0.49%), and one patient had diarrhea during the quarantine period of 15 days. Conclusion: The low PCR positivity rate in patients scheduled for elective surgery after a detailed history and physical examination raises the question whether elective surgery can be planned without testing. Pediatric surgeons can continue elective surgical procedures by taking precautions, but without requesting PCR, in patients who are asymptomatic and have no suspicious contact history.

O-197 Maternal and neonatal characteristics and outcomes of COVID-19 from early pregnancy until labor: an overview of systematic reviews

Study questionWhat is the current obstetric-perinatal and neonatal outcome of infected pregnant women and their newborns during the COVID-19 pandemic?Summary answerMiscarriage rates were <2.5%, even when only studies of moderate/high-quality were included. Increased rates of CS and preterm birth were found, with uncertain vertical transmission.What is known alreadyA considerable number of systematic reviews, with substantial heterogeneity regarding their methods and included populations, on the impact of COVID-19 on infected pregnant women and their neonates, has emerged.Study design, size, durationThree bibliographical databases were searched (last search: September 10, 2020). Quality assessment was performed using the AMSTAR-2 tool. Primary outcomes included mode of delivery, preterm delivery/labor, premature rupture of membranes (PROM/pPROM) and abortions/miscarriages. Outcomes were mainly presented as ranges. A separate analysis, including only moderate and high-quality systematic reviews, was also conducted. The protocol was registered with PROSPERO (CRD42020214447);Participants/materials, setting, methodsThe search strategy followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guideline. Keywords employed were (COVID-19 OR SARS-CoV-2 OR “Coronavirus disease 2019”) AND (“Neonatal outcom*” OR “Neonatal characteristic*” OR “Maternal outcom*” OR “maternal characteristic*” OR “pregnancy outcom*” OR “vertical transmission”). All retrieved studies were imported into the Rayyan QCRI and duplicated articles were removed. A snow-ball procedure was also implemented by hand-searching the reference lists of included systematic reviews for additional sources.Main results and the role of chanceThirty-nine reviews were analyzed. Twelve reviews (30.8%) were found to be of “very low quality”, 11 of “low quality”, 13 (33.3%) of “moderate”, and three (7.7%) of “high quality”.Ten articles dealt with miscarriages. One review integrated them into pregnancy terminations (1.4% (4/295)), one into intrauterine fetal deaths (1(3%)), while another one described them as “spontaneous abortions” (0.8% (3/385)). Taking into account reviews, which calculated these rates for their entire included population, miscarriage rates were <2.5%. The reported rates by moderate and high-quality studies were ≤ 2%. Reported rates,regarding both preterm and term gestations, varied between 52.3%-95.8% for caesarean sections; 4.2%-44.7% for vaginal deliveries; 14.3%-63.8% specifically for preterm deliveries and 22.7%-32.2% for preterm labor; 5.3%-12.7% for PROM and 6.4%-16.1% for pPROM. Maternal anxiety for potential fetal infection contributed to abortion decisions, while SARS-CoV-2-related miscarriages could not be excluded. Maternal ICU admission and mechanical ventilation rates were 3%-28.5% and 1.4%-12%, respectively. Maternal mortality rate was <2%, while stillbirth, neonatal ICU admission and mortality rates were <2.5%, 3.1%-76.9% and <3%, respectively. Neonatal PCR positivity rates ranged between 1.6% and 10%. After accounting for quality of studies, ranges of our primary outcomes remained unchanged.Limitations, reasons for cautionResults are presented in a narrative way using ranges as the primary mean of quantification. We also included studies with both RT-PCR positive women and women with suspected infection based on their clinical and imaging manifestations, whereas, if excluding them, we might have missed a considerable source of information.Wider implications of the findingsIn conclusion, a rapid increase of CS was observed, especially at the beginning of the pandemic, most likely due to lack of knowledge and robust recommendations. Preterm birth rates were elevated, with iatrogenic reasons potentially involved. Even though neonatal infections were rare, the probability of vertical transmission cannot be eliminated.Trial registration numbernot applicable’

SARS-CoV-2 PCR positivity rate and seroprevalence of related antibodies among a sample of patients in Cairo: Pre-wave 2 results of a screening program in a university hospital.

Research has revealed that asymptomatic and pre-symptomatic infections are important contributors to the transmission of SARS-CoV-2 in populations. In Egypt, the true prevalence of infections is veiled due to the low number of screening tests. The aim of this study was to determine the SARS-CoV-2 PCR positivity rate as well the seroprevalence of the SARS-CoV-2 antibodies before the ultimate development of a second wave of the epidemic in Cairo, Egypt. Our study was carried out between May 5 and the end of October 2020. It included all patients requiring admission to Ain Shams University hospitals. An interview questionnaire was used to collect demographic and clinical data. Laboratory tests for all participants included RT-PCR and total antibody assay for SARS-CoV-2. A total of 4,313 subjects were enrolled in our study, with females representing 56% of the sample. Adults and middle-aged individuals represented around 60% of the study sample. The positivity rate of SARS-CoV-2 PCR was 3.84% (95% CI 3.29-4.48), and the SARS-CoV-2 antibody seroprevalence was 29.82% (95% CI: 28.16-31.51). Males showed a higher risk for getting the COVID-19 infection, while middle-age group had significantly higher antibody seroprevalence rates. SARS-CoV-2 infection imposes a high burden on the community as detected by high seroprevalence rates.

COVID-19 herd immunity by immunisation: are children in the herd?

COVID-19 herd immunity by immunisation: are children in the herd?

Low pH Hypromellose (Taffix) nasal powder spray could reduce SARS-CoV-2 infection rate post mass-gathering event at a highly endemic community: an observational prospective open label user survey

ABSTRACT Objectives: Bney Brak city tops Israel’s COVID-19 infection rate and mortality. Before the Jewish New Year (two-day gathering) SARS-CoV-2 PCR positivity rates were 17.6% and reached 28.1% two weeks later Taffix – an innovative nasal powder creates a protective gel over the nasal mucosa blocking viruses from infecting nasal cells, was tested for efficacy in preventing SARS CoV2 infection. Methods: In a prospective users survey, 243 members of an ultra-orthodox community that participated in two days prayers were followed for 14 days following this ‘superspread’ event. Eighty-three used Taffix throughout holiday’s prayers and the following two weeks (ITT). Eighty-one used it regularly (PP). Two used it rarely if at all. The remaining 160 did not use Taffix. Results: After 14 days, 0/81 (0%) of (PP) Tafffix users, 2/83 (2.4%) of (ITT) Taffix users and 16/160 (10%) nonusers were infected. Odds ratio for infection among Taffix users was 0.22, a reduction of 78% (95%CI 1%–95%). No side effects reported. Conclusion: Taffix could be an additional tool against COVID19 spread, in addition to recommended safety measures. This is the first time that a prevention measure of SARS-CoV-2, beyond the use of masks, has proved effective.

Is there a role for SARS-CoV-2 antigen testing in the post-containment strategy?

BackgroundWith the availability and widespread deployment of antigenic tests for SARS-CoV-2 during the second epidemic wave in Europe, the performance of such tests in real-life situations is beginning to become available. ObjectivesThe question of the role of these tests during periods of low circulation of the virus has been legitimately raised. Study designWe addressed this question by analyzing the results of more than 16,000 SARS-CoV-2 PCRs during the first half of 2020 in a French region heavily affected by COVID-19. We were thus able to calculate and extrapolate the theoretical sensitivity of the antigenic tests for various periods during and after the first epidemic wave. ResultsAs the PCR-positivity rate of nasopharyngeal swabs declined over time, the proportion of samples with low Ct levels also decreased. Thus, the calculation of the analytical sensitivity of the antigenic tests ranged from 70 to 80% when the percentage of PCR positivity was > 1%, but fell below this score when it was lower. ConclusionsThe performance and relevance of antigenic tests appears to be more limited during phases of low circulation of the virus. This may have a negative impact on the effectiveness of isolation, testing, and contact tracing strategies.

Reopening schools in the context of increasing COVID-19 community transmission: The French experience

Background and objectivesThe role of schools in the spread of SARS-CoV-2 infections in the community is still controversial. The objective of our study was to describe the epidemiology of SARS-CoV-2 infections in different pediatric age groups during the first 2 months of the fall back-to-school period, in the context of increasing viral transmission in France. MethodsWeekly epidemiological data provided by Santé Publique France and the Ministry of National Education were analyzed according to the age groups defined by the different school levels. Weeks (W) 34–42 were considered for analysis. ResultsThe PCR positivity rate and incidence rate increased in all age groups during the study period, in an age-dependent manner. At W42, with adults being considered as reference, the risk ratio for a positive PCR test was 0.46 [95% CI: 0.44–0.49] and 0.69 [0.68–0.70] for children aged 0–5 years and 6–17 years, respectively. Similarly, the incidence rate ratio was 0.09 [0.08–0.09], 0.31 [0.30–0.32], 0.64 [0.63–0.66], and 1.07 [1.05–1.10] for children aged 0–5 years, 6–10 years, 11–14 years, and 15–17 years, respectively. Children and adolescents accounted for 1.9% of the newly hospitalized patients between W34 and W42, and for 1.3% of new intensive care admissions. No death was observed. Among infected children and adolescents, the percentage of asymptomatic individuals was 57% at W34 and 48% at W42. The number of schools closed remained low, less than 1% throughout the study period. The number of confirmed cases among school staff was consistent with the data measured in the general population. ConclusionIn the context of increasing viral transmission in the population, the spread among children and adolescents remained lower than that observed among adults, despite keeping schools open. However, the impact was age-dependent, with data in high schools close to those observed in adults.

The role of children in the spread of COVID-19: Using household data from Bnei Brak, Israel, to estimate the relative susceptibility and infectivity of children.

One of the significant unanswered questions about COVID-19 epidemiology relates to the role of children in transmission. This study uses data on infections within households in order to estimate the susceptibility and infectivity of children compared to those of adults. The data were collected from households in the city of Bnei Brak, Israel, in which all household members were tested for COVID-19 using PCR (637 households, average household size of 5.3). In addition, serological tests were performed on a subset of the individuals in the study. Inspection of the PCR data shows that children are less likely to be tested positive compared to adults (25% of children positive over all households, 44% of adults positive over all households, excluding index cases), and the chance of being positive increases with age. Analysis of joint PCR/serological data shows that there is under-detection of infections in the PCR testing, which is more substantial in children. However, the differences in detection rates are not sufficient to account for the differences in PCR positive rates in the two age groups. To estimate relative transmission parameters, we employ a discrete stochastic model of the spread of infection within a household, allowing for susceptibility and infectivity parameters to differ among children and adults. The model is fitted to the household data using a simulated maximum likelihood approach. To adjust parameter estimates for under-detection of infections in the PCR results, we employ a multiple imputation procedure using estimates of under-detection in children and adults, based on the available serological data. We estimate that the susceptibility of children (under 20 years old) is 43% (95% CI: [31%, 55%]) of the susceptibility of adults. The infectivity of children was estimated to be 63% (95% CI: [37%, 88%]) relative to that of adults.

Impact of Hydroxychloroquine Used as DMARD on SARS CoV-2 Tests and COVID-19 Evolution

Objectives: Data remain scarce on the impact of long-term hydroxychloroquine (HCQ) treatment on infection with SARS CoV-2. Our aim was to analyse the data of COVID-19 patients with inflammatory rheumatic and musculoskeletal diseases (iRMD-COVID-19 patients), and to compare those receiving HCQ as disease-modifying anti-rheumatic drug (DMARD) with those not receiving the drug.Methods: From the French iRMD-COVID-19 cohort, data on COVID-19 in patients receiving HCQ were compared to those of patients not receiving HCQ at the time of infection. Matching criteria were age, gender, comorbidities, immunosuppressive treatment and use of nasopharyngeal PCR test.Results: Among the 871 patients, 71 treated with HCQ prior to COVID-19 were matched with and compared to 191 controls. There was no significant difference between cases and controls in terms of nasopharyngeal PCR-positive rate (85% vs 81%; absolute standardized difference = 6.0%), clinical symptoms, rate of hospitalization (33.8% vs 27.7%; OR=1.75 (0.86-3.56); p=0.12), rate of severe form (admission to intensive care unit/death) (11.3% vs 9.4%; OR=1.94 (0.69-5.41); p=0.21).Conclusions: In a cohort of patients with iRMD, treatment with HCQ as DMARD did not modify either the SARS-CoV-2 nasopharyngeal PCR-positive rate or the clinical presentation and did not reduce the occurrence of severe forms of SARS CoV-2 infection, compared to patients not receiving HCQ.Trial Registration: ClinicalTrials.gov (NCT04353609).Funding Statement: This study was not supported by research funding, but FAI2R is funded by the French Ministry of Social Affairs and Health (ministère des solidarités et de la santé).Declaration of Interests: The authors have no competing interests.Ethics Approval Statement: Under French law, ethics committee approval was not required. The study was performed in compliance with MR-004, received permission from Lille University Hospital, and was declared to the Commission Nationale de l’Informatique et des Libertés (reference DEC20-107).