SARS-CoV-2 Antibody Prevalence in Unvaccinated Children and Change in Antibody Levels Between 2020-2022

Abstract

After the declaration of the COVID-19 pandemic by the World Health Organization (WHO), various restrictions were implemented, and face-to-face education was suspended in schools. In some countries, COVID-19 vaccines emergency use authorization has been granted for the pediatric age group. This study aimed to investigate COVID-19 antibody level in children who have not been vaccinated against COVID-19. A total of 1,000 pediatric patients aged 0-12 years, unvaccinated against COVID-19, admitted to Necmettin Erbakan University Medical Faculty Hospital Pediatrics clinics with different symptoms between October 2020 and April 2022 were included in this study. SARS-CoV-2 S total antibody levels were tested by ELISA method from the sera samples of these children. Of the children included in the study, 535 (53.5%) were male and 465 (46.5%) were female. Anti-SARS-CoV-2 S total Ig positivity rates were 75.9% in girls and 78.5% in boys and the difference between them was not statistically significant (p>0.05). When the anti-SARS-CoV-2 S total Ig positivity rates of children were evaluated according to years, 23 (43.4%) in 2020, 183 (60%) in 2021, and 567 (88.3%) in 2022 was found positive. The difference between antibody results by years was found to be statistically significant (p<0.001). Median value of SARS-CoV-2 antibody levels of patients with positive antibody test in 2020 46 AU/ml (min 5, max: 214 AU/ml), in 2021 130 AU/ml (min:1, max: 250 AU/ml), and in 2022 it was found to be 250 AU/ml (min:1, max: 250 AU/ml). When the antibody levels of patients with anti-SARS-CoV-2 S Ig total positive were evaluated, the difference between years was found to be statistically significant (p<0.05). In our study, it was determined that the rate of SARS-CoV-2 S total antibody positivity reached 90% in unvaccinated children aged 12 and younger. Determining the SARS-CoV-2 antibody status of children aged 12 and under who unvaccinated against COVID-19 in our country will both give information about immunization by natural immunity and will be effective in deciding and planning the need for COVID-19 vaccination for children.