SARS-CoV-2 Antibody Prevalence and Associated Factors in COVID-19-Unvaccinated Children: A Cross-sectional Study

Understanding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposures among unvaccinated children, particularly the impact of activities, masking behaviors, and household characteristics, remains limited. This study examines associations between masking behaviors, out-of-home activities, and household characteristics with SARS-CoV-2 infection among inner-city children.

Cross-sectional data were obtained from the New Jersey Department of Health's COVID Antibody Surveillance Project at Rutgers New Jersey Medical School. This study included 250 children (18 months-11 years) who had not received SARS-CoV-2 vaccination. The children were recruited from the pediatric clinic. Guardians provided data on activity participation, masking behaviors, and household characteristics via an online survey. SARS-CoV-2 antibodies were assessed using the Diabetomics CovAb oral gum swab test.

Antibody positivity was 67.1% for the preschool cohort (18 months-5 years) and 70.5% for the school-age children (5-11 years). Antibody positivity was higher for children in households without vaccinated adults (82.1%) compared with those with at least 1 vaccinated adult (63.9%) ( P = 0.03). Antibody positivity did not significantly differ by household size: 68.1% in the 2-4-member group, 66.2% in the 5-7-member group, and 40% in the 8- or more-member group. No significant differences in antibody positivity were found between children participating in school and nonschool-based activities, masking during activities, or households with/without members reporting a history of SARS-CoV-2 illness.

This study did not find a significant link between antibody positivity and household size, household member history of SARS-CoV-2 illness, activities, or masking. There is a relationship between vaccination of household members and lower antibody positivity rates.