Serological testing of young children indicated there was little risk for SARS-CoV-2 transmission at daycare centers, according to findings were published in the Lancet Child and Adolescent Health.
After a nationwide lockdown in France, all staff and parents of children at 22 daycare centers in Paris were invited to participate in this cross-sectional, multicenter, seroprevalence study. A group of administrative and laboratory employees from 6 hospitals in Paris were recruited as a comparator cohort. Participants were tested for infection with nasopharyngeal swabs and gave capillary whole blood by fingerstick, which was tested for SARS-CoV-2 immunoglobulins (Ig)G and IgM.
The 3 cohorts comprised 197 daycare staff, 327 children, and 164 participants as the control group.
The daycare centers had between 8 and 56 children attending daily (median, 24). Participating children were aged mean 1.9 years (range, 5 months-4.4 years) and 51% were boys. The daycare staff were 99% women aged mean age of 40 years.
No children tested positive for SARS-CoV-2. The raw seropositivity rate was 4.3% (95% CI, 2.6-7.1%) among the children and 7.7% (95% CI, 4.2-11.6%) among the staff, compared with 5.5% (95% CI, 2.9-10.1%) among the comparator group. The 14 children who were seropositive attended 13 different centers and the 14 staff members who were seropositive worked at 8 different centers, indicating there was little risk for daycare transmission.
Seropositivity was associated with children who lived with an adult who had a confirmed COVID-19 infection (relative risk [RR], 7.1; 95% CI, 2.2-22.4), who had a seropositive parent (RR, 6.1; 95% CI, 1.9-19.1), and who had a confirmed contact with COVID-19 (RR, 3.5; 95% CI, 1.2-10.7).
Among daycare staff, seropositivity was associated with previous symptoms of anosmia (RR, 13.1; 95% CI, 2.8-60.1), ageusia (RR, 8.7; 95% CI, 2.1-35.9), loss of appetite (RR, 5.4; 95% CI, 1.6-18.8), myalgia (RR, 4.4; 95% CI, 1.3-14.7), and joint pain (RR, 4.1; 95% CI, 1.2-13.7). In addition to previous COVID-19 symptoms, seropositivity was associated with previously testing positive (RR, 32.0; 95% CI, 1-945) and living with another adult who had confirmed COVID-19 (RR, 17.2; 95% CI, 2.1-140.8) among the comparator group.
Seropositivity was not associated with working at a daycare center (RR, 1.5; 95% CI, 0.6-3.9).
This study may have been limited by using a fingerstick approach for antibody testing, which has been shown to be less sensitive. The investigators chose this approach to maximize participation among the children.
These data did not indicate that daycare centers have higher risk of SARS-CoV-2 spread and transmission compared with transmission within the family.
Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Lachassinne E, de Pontual L, Caseris M, et al. SARS-CoV-2 transmission among children and staff in daycare centres during a nationwide lockdown in France: a cross-sectional, multicentre, seroprevalence study. Lancet Child Adolesc Health. 2021;S2352-4642(21)00024-9. doi:10.1016/S2352-4642(21)00024-9.