ABSTRACT
BACKGROUND: The SARS-CoV-2 pandemic is ongoing in Germany. Children and adolescents are increasingly being infected, and many cases presumably remain undetected and unreported. Sero-epidemiological studies can help estimate the true number of infections. METHODS: From January 2020 to June 2022, 59 786 persons aged 1-17 years were tested for SARS-CoV-2 antibodies as part of a screening program for presymptomatic type 1 diabetes in the German federal state of Bavaria (the Fr1da study). RESULTS: In June 2022, the seroprevalence in the overall population was 73.5%. The seroprevalence was significantly higher in school-age children (from 5 to 10 years of age) than in preschool children (ages 1-4): 84.4% vs. 66.6%, p <0.001. In contrast, in November 2021, before the appearance of the omicron variant, the overall seroprevalence was 14.7% (16.2% of school-age children, 13.0% of preschool children, p = 0.06). In the overall collective, seroprevalence increased fivefold from the fall of 2021 to June 2022 (by a factor of 5.2 in school-age children and 5.1 in preschool children). Similar seroprevalences, with smaller case numbers, were observed in June 2022 in the corresponding Fr1da studies in Saxony and Northern Germany: 87.8% and 76.7%, respectively. CONCLUSION: Monthly case counts reveal a substantial rise in SARS-CoV-2-infections among children and adolescents from late 2021 to mid-2022. The high percentage of preschool and school-age children who have been infected with SARS-CoV-2, in a population that has low vaccination coverage, should be taken into account in the development of health policies.
ABSTRACT
This study screens more than 50â¯000 youths in diverse populations of Colorado and Bavaria to assess whether previous SARS-CoV-2 infection was associated with autoimmunity, which predicts future type 1 diabetes.
Subject(s)
COVID-19 , Diabetes Mellitus, Type 1 , Adolescent , Asymptomatic Diseases/epidemiology , Autoimmunity , COVID-19/epidemiology , Child , Colorado/epidemiology , Diabetes Mellitus, Type 1/epidemiology , Diabetes Mellitus, Type 1/immunology , Germany/epidemiology , Humans , SARS-CoV-2ABSTRACT
Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.
ABSTRACT
BACKGROUND: Antibody responses to virus reflect exposure and potential protection. METHODS: We developed a highly specific and sensitive approach to measuring antibodies against SARS-CoV-2 for population-scale immune surveillance. Antibody positivity was defined as a dual-positive response against both the receptor-binding domain and nucleocapsid proteins of SARS-CoV-2. Antibodies were measured by immunoprecipitation assays in capillary blood from 15,771 children aged 1 to 18 years living in Bavaria, Germany, and participating in a public health type 1 diabetes screening program (ClinicalTrials.gov: NCT04039945), in 1,916 dried blood spots from neonates in a Bavarian screening study (ClinicalTrials.gov: NCT03316261), and in 75 SARS-CoV-2-positive individuals. Virus positive incidence was obtained from the Bavarian health authority data. FINDINGS: Dual-antibody positivity was detected in none of the 3,887 children in 2019 (100% specificity) and 73 of 75 SARS-CoV-2-positive individuals (97.3% sensitivity). Antibody surveillance in children during 2020 resulted in frequencies of 0.08% in January to March, 0.61% in April, 0.74% in May, 1.13% in June, and 0.91% in July. Antibody prevalence from April 2020 was 6-fold higher than the incidence of authority-reported cases (156 per 100,000 children), showed marked variation between the seven Bavarian regions (p < 0.0001), and was not associated with age or sex. Transmission in children with virus-positive family members was 35%. 47% of positive children were asymptomatic. No association with type 1 diabetes autoimmunity was observed. Antibody frequency in newborns was 0.47%. CONCLUSIONS: We demonstrate the value of population-based screening programs for pandemic monitoring. FUNDING: The work was supported by funding from the BMBF (FKZ01KX1818).