SARS-CoV-2 seroprevalence in students and teachers: a longitudinal study from May to October 2020 in German secondary schools

[COVID-19 vaccination in children and adolescents]

Background

The COVID-19 pandemic posed special challenges for the existing structures for vaccination prevention in Germany with respect to 1) understanding the role and aims of those involved and the interests of the children and 2) the definition of adequate criteria and assessment of the risk of severe diseases in children.

Objectives

Do the priorities of different groups of interest differ in the recommendations for COVID-19 vaccination? Which data on the pathogenicity of different variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV‑2) are necessary and how did they change during the pandemic?

Methods

The tasks, objectives and perception of politics and the German national vaccination advisory committee regarding vaccination of children are discussed in the face of summarized recent data on clinical manifestations of pediatric SARS-CoV‑2 infections among children and adolescents in Germany, which could be estimated by combining different German data sources.

Results

The perspectives of politics and children differ but are legitimate when they are clearly stated. The decisive risk for a severe course or the pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV‑2 (PIMS-TS) per 10,000 SARS-CoV‑2 infections for the decision on vaccination from the perspective of children, decreased during the course of the pandemic with dominance of the omicron variant. Severe courses of COVID-19 still predominantly affect children with underlying diseases. The age-stratified analysis of vaccinated and nonvaccinated children showed that the alterations in the pathogenicity of the virus in the course of the pandemic is particularly reflected in the reduction in the risk of PIMS-TS. The general reduction of severe courses of COVID-19 again can be explained by the characteristics of variants of concern (VOC) as well as increasing vaccination rates and immunity following a SARS-CoV‑2 infection.

Conclusion

The primary goal of COVID-19 vaccination in children and adolescents is the prevention of severe courses of the disease. In pediatric risk groups the best possible immunity or immune protection by vaccination should be strived for. It is currently unclear whether catch-up vaccination in already infected or vaccinated children or whether forthcoming healthy children will need vaccination, aiming for hybrid immunity.

A longitudinal seroepidemiology study to evaluate antibody response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Canada from July 2020 to April 2022: Alberta COVID-19 Childhood Cohort (AB3C) Study

BACKGROUND

Measurement of SARS-CoV-2 antibody seropositivity is important to accurately understand exposure to infection and/or vaccination in specific populations. This study aimed to estimate the serologic response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Alberta over a two-year period.

METHODS

Children with or without prior SARS-CoV-2 infections, were enrolled in Calgary, Canada in 2020. Venous blood was sampled 4 times from July 2020 to April 2022 for SARS-CoV-2 nucleocapsid and spike antibodies. Demographic and clinical information was obtained including SARS-CoV-2 testing results and vaccination records.

RESULTS

1035 children were enrolled and 88.9% completed all 4 visits; median age 9 years (IQR: 5,13); 519 (50.1%) female; and 815 (78.7%) Caucasian. Before enrolment, 118 (11.4%) had confirmed or probable SARS-CoV-2. By April 2022, 39.5% of previously uninfected participants had a SARS-CoV-2 infection. Nucleocapsid antibody seropositivity declined to 16.4% of all infected children after more than 200 days post diagnosis. Spike antibodies remained elevated in 93.6% of unvaccinated infected children after more than 200 days post diagnosis. By April 2022, 408 (95.6%) children 12 years and older had received 2 or more vaccine doses, and 241 (61.6%) 5 to 11 year-old children had received 2 vaccine doses. At that time, all 685 vaccinated children had spike antibodies, compared with 94/176 (53.4%) of unvaccinated children.

CONCLUSIONS

In our population, after the first peak of Omicron variant infections and introduction of COVID-19 vaccines for children, all vaccinated children, but just over one-half of unvaccinated children, had SARS-CoV-2 spike antibodies indicating infection and/or vaccination, highlighting the benefit of vaccination. It is not yet known whether a high proportion of seropositivity at the present time predicts sustained population-level protection against future SARS-CoV-2 transmission, infection or severe COVID-19 outcomes in children.

Impact of the COVID-19 Pandemic Regulations on the Health Status and Medical Care of Children with Trisomy 21

BACKGROUND

While children are considered at low risk for COVID-19, little is known about the impact of SARS-CoV-2 on paediatric risk patients like children with Trisomy 21 (T21). As these children often need regular therapy and various medical appointments, this study aimed to investigate the possible impact of the COVID-19 pandemic on children with T21.

PATIENTS AND METHODS

Parents of children with T21 in the age of 0-12 years in Saxony-Anhalt were interviewed via phone in June 2021 regarding the health status and medical care of their children during the past 15 months of pandemic.

RESULTS

37 children with mean age of 6.1 years (min 0; max 12) were included in the study. The majority did not have any additional congenital anomalies. Surveyed parents hardly reported adverse changes of health status during the pandemic, but rather improvements, such as decreased number of respiratory infections and more time spend with their children. Outpatient appointments and therapy were cancelled or postponed at the onset of the pandemic, but parents reported low impact on their child's health and development. The main concern seemed to be lack of childcare during school and day-care closures and uncertainty concerning possible health impacts of an infection on their children.

CONCLUSION

There was low impact of the COVID-19 pandemic on health and medical care of children with T21 in our study population. Further research is needed to help weigh the child's individual risk of infection against the need for medical treatment and therapy when dealing with paediatric risk patients.

The COVID-19 Sentinel Schools Network of Catalonia (CSSNC) project: Associated factors to prevalence and incidence of SARS-CoV-2 infection in educational settings during the 2020-2021 academic year

The Sentinel Schools project was designed to monitor and evaluate the epidemiology of COVID-19 in Catalonia, gathering evidence for health and education policies to inform the development of health protocols and public health interventions to control of SARS-CoV-2 infection in schools. The aim of this study was to estimate the prevalence and incidence of SARS-CoV-2 infections and to identify their determinants among students and staff during February to June in the academic year 2020-2021. We performed two complementary studies, a cross-sectional and a longitudinal component, using a questionnaire to collect nominal data and testing for SARS-CoV-2 detection. We describe the results and perform a univariate and multivariate analysis. The initial crude seroprevalence was 14.8% (95% CI: 13.1-16.5) and 22% (95% CI: 18.3-25.8) for students and staff respectively, and the active infection prevalence was 0.7% (95% CI: 0.3-1) and 1.1% (95% CI: 0.1-2). The overall incidence for persons at risk was 2.73 per 100 person-month and 2.89 and 2.34 per 100 person-month for students and staff, respectively. Socioeconomic, self-reported knowledge, risk perceptions and contact pattern variables were positively associated with the outcome while sanitary measure compliance was negatively associated, the same significance trend was observed in multivariate analysis. In the longitudinal component, epidemiological close contact with SARS-CoV-2 infection was a risk factor for SARS-CoV-2 infection while the highest socioeconomic status level was protective as was compliance with sanitary measures. The small number of active cases detected in these schools suggests a low transmission among children in school and the efficacy of public health measures implemented, at least in the epidemiological scenario of the study period. The major contribution of this study was to provide results and evidence that help analyze the transmission dynamic of SARS-CoV-2 and evaluate the associations between sanitary protocols implemented, and measures to avoid SARS-CoV-2 spread in schools.

Incidence of Type 1 Diabetes in Children and Adolescents During the COVID-19 Pandemic in Germany: Results From the DPV Registry

OBJECTIVE

The aim of this study was to investigate the incidence of type 1 diabetes in children and adolescents during the coronavirus disease 2019 (COVID-19) pandemic in Germany compared with previous years.

RESEARCH DESIGN AND METHODS

Based on data from the multicenter German Diabetes Prospective Follow-up Registry, we analyzed the incidence of type 1 diabetes per 100,000 patient-years in children and adolescents from 1 January 2020 through 30 June 2021. Using Poisson regression models, expected incidences for 2020/21 were estimated based on the data from 2011 to 2019 and compared with observed incidences in 2020/21 by estimating incidence rate ratios (IRRs) with 95% CIs.

RESULTS

From 1 January 2020 to 30 June 2021, 5,162 children and adolescents with new-onset type 1 diabetes in Germany were registered. The observed incidence in 2020/21 was significantly higher than the expected incidence (24.4 [95% CI 23.6-25.2] vs. 21.2 [20.5-21.9]; IRR 1.15 [1.10-1.20]; P < 0.001). IRRs were significantly elevated in June 2020 (IRR 1.43 [1.07-1.90]; P = 0.003), July 2020 (IRR 1.48 [1.12-1.96]; P < 0.001), March 2021 (IRR 1.29 [1.01-1.65]; P = 0.028), and June 2021 (IRR 1.39 [1.04-1.85]; P = 0.010).

CONCLUSIONS

A significant increase in the incidence of type 1 diabetes in children was observed during the COVID-19 pandemic, with a delay in the peak incidence of type 1 diabetes by ∼3 months after the peak COVID-19 incidence and also after pandemic containment measures. The underlying causes are yet unknown. However, indirect rather than direct effects of the pandemic are more likely to be the cause.

SARS-CoV-2 Circulation in the School Setting: A Systematic Review and Meta-Analysis

The contribution of children to viral spread in schools is still debated. We conducted a systematic review and meta-analysis of studies to investigate SARS-CoV-2 transmission in the school setting. Literature searches on 15 May 2021 yielded a total of 1088 publications, including screening, contact tracing, and seroprevalence studies. MOOSE guidelines were followed, and data were analyzed using random-effects models. From screening studies involving more than 120,000 subjects, we estimated 0.31% (95% confidence interval (CI) 0.05–0.81) SARS-CoV-2 point prevalence in schools. Contact tracing studies, involving a total of 112,622 contacts of children and adults, showed that onward viral transmission was limited (2.54%, 95% CI 0.76–5.31). Young index cases were found to be 74% significantly less likely than adults to favor viral spread (odds ratio (OR) 0.26, 95% CI 0.11–0.63) and less susceptible to infection (OR 0.60; 95% CI 0.25–1.47). Lastly, from seroprevalence studies, with a total of 17,879 subjects involved, we estimated that children were 43% significantly less likely than adults to test positive for antibodies (OR 0.57, 95% CI 0.49–0.68). These findings may not applied to the Omicron phase, we further planned a randomized controlled trial to verify these results.

Seroprevalence of SARS-CoV-2 in German secondary schools from October 2020 to July 2021: a longitudinal study

Purpose

To quantify the number of SARS-CoV-2 infections in students and teachers in 14 Secondary schools in eastern Saxony, Germany. Seroprevalence of SARS-CoV-2 antibodies in study population. Number of undetected cases.

Methods

Serial seroprevalence study.

Results

The role of educational settings in the SARS-CoV-2 Pandemic is still controversial. Seroprevalence increases from 0.8 to 5.9% from October to December when schools remained open and to 12.2% in March/April during a strict lockdown with closed schools. The ratio of undetected to detected cases decreased from 0.76 to 0.44 during the study period.

Conclusion

During the second and third wave of the pandemic in Germany, students and teachers are not overrepresented in SARS-CoV-2 infections. The percentage of undetected cases is moderate and decreases over time. The risk of contracting SARS-CoV-2 within the household is higher than contracting it in educational settings making school closures rather ineffective in terms of pandemic control measures or individual risk reduction in children and adolescents.

Trial registration

DRKS00022455 (July 23rd, 2020).

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-022-01824-9.

Comparison of mental health outcomes in seropositive and seronegative adolescents during the COVID19 pandemic

Post-COVID19 complications such as pediatric inflammatory multisystem syndrome (PIMS) and Long-COVID19 move increasingly into focus, potentially causing more harm in young adolescents than the acute infection. To better understand the symptoms of long-term mental health outcomes in adolescents and distinguish infection-associated symptoms from pandemic-associated symptoms, we conducted a 12 question Long-COVID19 survey. Using this survey, we compared the responses on neurocognitive, general pain and mood symptoms from seropositive and seronegative adolescents in a cross-sectional study design. Since May 2020, students grade 8–12 in fourteen secondary schools in Eastern Saxony were enrolled in the SchoolCovid19 study. Serostatus was assessed regularly in all participants. In March/April 2021, 1560 students with a median age of 15 years participated at the regular study visit after re-opening of the schools in mid-March and responded to our Long-COVID19 survey as part of this visit. 1365 (88%) students were seronegative, 188 (12%) were seropositive. Each symptom asked in the Long-COVID19 survey was present in at least 35% of the students within the last seven days before the survey. With the exception of seropositive students being less sad, there was no significant difference comparing the reported symptoms between seropositive students and seronegative students. The lack of differences comparing the reported symptoms between seropositive and seronegative students suggests that Long-COVID19 might be less common than previously thought and emphasizes on the impact of pandemic-associated symptoms regarding the well-being and mental health of young adolescents.

Clinical Trial Registration: SchoolCoviDD19: Prospektive Erfassung der SARS-CoV-2 Seropositivität bei Schulkindern nach Ende der unterrichtsfreien Zeit aufgrund der Corona-Schutz-Verordnung (COVID-19), DRKS00022455, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00022455

Risk for severe outcomes of COVID-19 and PIMS-TS in children with SARS-CoV-2 infection in Germany

Although children and adolescents have a lower burden of SARS-CoV-2-associated disease compared to adults, assessing the risk for severe outcomes among SARS-CoV-2-infected children remains difficult due to a high rate of undetected cases. We combine data from three data sources - a national seroprevalence study (the SARS-CoV-2 KIDS study), the nationwide, state-based reporting system for PCR-confirmed SARS-CoV-2 infections in Germany, and a nationwide registry on children and adolescents hospitalized with either SARS-CoV-2 or pediatric inflammatory multisystem syndrome (PIMS-TS, also known as MIS-C) - in order to provide estimates on the risk of hospitalization for COVID-19-related treatment, intensive care admission, and death due to COVID-19 and PIMS-TS in children. The rate of hospitalization for COVID-19-related treatment among all SARS-CoV-2 seropositive children was 7.13 per 10,000, ICU admission 2.21 per 10,000, and case fatality was 0.09 per 10,000. In children without comorbidities, the corresponding rates for severe or fatal disease courses were substantially lower. The lowest risk for the need of COVID-19-specific treatment was observed in children aged 5-11 without comorbidities. In this group, the ICU admission rate was 0.37 per 10,000, and case fatality could not be calculated due to the absence of cases. The overall PIMS-TS rate was 2.47 per 10,000 SARS-CoV-2 infections, the majority being children without comorbidities.

CONCLUSION

Overall, the SARS-CoV-2-associated burden of a severe disease course or death in children and adolescents is low. This seems particularly the case for 5-11-year-old children without comorbidities. By contrast, PIMS-TS plays a major role in the overall disease burden among all pediatric age groups.

WHAT IS KNOWN

• SARS-CoV-2-associated burden of disease in children is considered to be low, but accurate risk estimates accounting for clinically undiagnosed infections are lacking. • Asymptomatic SARS-CoV-2 infections are common in children.

WHAT IS NEW

• We provide risk estimates for hospitalization for COVID-19-related treatment, ICU admission, death from COVID-19, and PIMS-TS for children with SARS-CoV-2 infections by pooling different data sources. • The risk for PIMS-TS exceeds the risk for severe COVID-19 in all age groups; the risk for severe COVID-19 is the lowest in 5-11 years old.

Transmission of SARS-CoV-2 by children and young people in households and schools: a meta-analysis of population-based and contact-tracing studies

Background The role of children and young people (CYP) in transmission of SARS-CoV-2 in household and educational settings remains unclear. We undertook a systematic review and meta-analysis of contact-tracing and population-based studies at low risk of bias. Methods We searched 4 electronic databases on 28 July 2021 for contact-tracing studies and population-based studies informative about transmission of SARS-CoV-2 from 0-19 year olds in household or educational settings. We excluded studies at high risk of bias, including from under-ascertainment of asymptomatic infections. We undertook multilevel random effects meta-analyses of secondary attack rates (SAR: contact-tracing studies) and school infection prevalence, and used meta-regression to examine the impact of community SARS-CoV-2 incidence on school infection prevalence. Findings 4529 abstracts were reviewed, resulting in 37 included studies (16 contact-tracing; 19 population studies; 2 mixed studies). The pooled relative transmissibility of CYP compared with adults was 0.92 (0.68, 1.26) in adjusted household studies. The pooled SAR from CYP was lower (p=0.002) in school studies 0.7% (0.2, 2.7) than household studies (7.6% (3.6, 15.9) . There was no difference in SAR from CYP to child or adult contacts. School population studies showed some evidence of clustering in classes within schools. School infection prevalence was associated with contemporary community 14-day incidence (OR 1.003 (1.001, 1.004), p<0.001). Interpretation We found no difference in transmission of SARS-CoV-2 from CYP compared with adults within household settings. SAR were markedly lower in school compared with household settings, suggesting that household transmission is more important than school transmission in this pandemic. School infection prevalence was associated with community infection incidence, supporting hypotheses that school infections broadly reflect community infections. These findings are important for guiding policy decisions on shielding, vaccination school and operations during the pandemic.

[Seroprevalence of SARS-CoV-2 among children and adolescents in Germany-an overview]

Hintergrund

SARS-CoV-2-Antikörperstudien ergänzen und erweitern die Erkenntnisse aus der Meldestatistik laborbestätigter COVID-19-Fälle um Informationen zu unentdeckten Fällen.

Ziel der Arbeit

Der vorliegende Beitrag fasst bisherige Ergebnisse zur SARS-CoV-2-Prävalenz aus seroepidemiologischen Studien in Deutschland zusammen, die sich auf Kinder und Jugendliche konzentrieren, und ergänzt die bereits vorliegende Übersicht zur Seroprävalenz bei Erwachsenen und speziell bei Blutspendenden in Deutschland.

Material und Methoden

Die Ergebnisse der Übersichtsarbeit beruhen auf einer fortlaufenden systematischen Recherche in Studienregistern, Literaturdatenbanken, von Preprint-Veröffentlichungen und Medienberichten seroepidemiologischer Studien in Deutschland sowie deren Ergebnissen.

Ergebnisse

Mit Stand 17.09.2021 sind uns 16 deutsche seroepidemiologische Studien, die sich auf Kinder und Jugendliche konzentrieren, bekannt geworden. Für 9 dieser Studien liegen Ergebnisse vor. Für fast alle untersuchten Settings lag die SARS-CoV-2-Seroprävalenz für Kinder im Kita- und Grundschulalter in der ersten COVID-19-Welle deutlich unter 1 % und für Jugendliche unter 2 %. Im Verlauf der Pandemie wurden höhere Seroprävalenzen von bis zu 8 % für Kinder im Grundschulalter ermittelt.

Diskussion

Ergebnisse von SARS-CoV-2-Antikörperstudien bei Kindern und Jugendlichen in Deutschland liegen bislang erst in geringem Umfang und basierend auf lokal-regionalen, nichtrepräsentativen Stichproben vor. In künftigen Studien gilt es, einerseits abzuschätzen, welcher Anteil der Kinder und Jugendlichen bereits eine Infektion hatte oder geimpft ist. Zum anderen gilt es, die Verbreitung körperlicher und psychischer Beeinträchtigungen im Nachgang einer Infektion zu untersuchen.

Calculating the number of undetected active SARS-CoV-2 infections from results of population-wide antigen tests

Current European research estimates the number of undetected active SARS-CoV-2 infections (dark figure) to be two- to 130-fold the number of detected cases. We revisited the population-wide antigen tests in Slovakia and South Tyrol and calculated the dark figure of active cases in the vulnerable populations and the number of undetected active cases per detected active case at the time of the population-wide tests. Our analysis follows three steps: using the sensitivities and specificities of the used antigen tests, we first calculated the number of test-positive individuals and the proportion of actual positives in those who participated in the antigen tests. We then calculated the dark figure in the total population of Slovakia and South Tyrol, respectively. Finally, we calculated the ratio of the dark figure in the vulnerable population to the number of newly detected infections through PCR tests. Per one positive PCR result, another 0.15 to 0.71 cases must be added in South Tyrol and 0.01 to 1.25 cases in Slovakia. The dark figure was in both countries lower than assumed by earlier studies.