Children and young people are at the least risk of coronavirus infection and the consequences of COVID-19. However, COVID-19 has dramatically affected their lives due to many months of school closures intended to prevent the spread of the infection. In the Czech Republic, secondary schools were closed from 14 October 2020 to 24 May 2021 with a short break before Christmas. However, the students were most often infected by their parents, who usually became infected at work. The aim of this study was to find out by means of antibody testing how many high school students in Havlíčkův Brod have undergone the infection. We used questionnaires to find out how many students were in quarantine. The group included 196 students aged 15-19. Examination of IgG antibodies against the S antigen (Abbott, Architect) was performed in June 2021. Antibodies were detected in 90 of 196 students (45.9%). Coronavirus infection was reported in 88 families. Antibodies were detected in 61 quarantined students (69.3%), while the remaining 27 students had neither antibodies, nor clinical signs, nor positive PCR test. Thus, these students are considered unsusceptible to the infection at the time of quarantine. Despite the interruption of teaching in schools and the associated reduction of contacts, a significant share of students met with the coronavirus. About half of the students in the sample are already largely resistant to the disease (have antibodies). Another part of the students was unsusceptible to the disease, because they did not fall sick despite having been in contact with an infected family member.
Keywords: Antibodies; COVID-19; SARS-CoV-2; adolescent; adolescents; antibodies; body mass index; children; coronavirus; seroprevalence; unsusceptibility.