SARS-CoV-2 infection in children of healthcare workers

Secondary attack rate and family clustering of SARS-CoV-2 infection in children of healthcare workers with confirmed COVID-19

Authors: Mathuramat Seesen, Roberto G Lucchini, Somkiat Siriruttanapruk, Ratana Sapbamrer, Surat Hongsibsong, Susan Woskie, Pornpimol Kongtip


We measured serum SARS-CoV-2 antibodies in 215 children of healthcare workers to estimate secondary attack rates (SAR). Twenty-one families had a parent with confirmed COVID-19. There was strong evidence of family clustering (P<0.001): 20/21 (95.2%) children were seropositive in 9 families and none of 23 children in 12 other families.


Children are relatively protected against coronavirus disease 2019 (COVID-19) compared to adults. Exposure to SARS-CoV-2, the virus responsible for COVID-19, typically results in asymptomatic infection or a mild, transient illness that rarely requires hospitalisation and is rarely fatal in children. Systematic reviews of contact tracing studies estimate that children are 54% less likely to develop COVID-19 compared to adults, while household transmission studies suggest a 3-fold lower risk of COVID-19 in children than in adults. Such transmission studies, however, invariably utilised upper respiratory tract swabs to identify SARS-CoV-2 infection among contacts of confirmed cases, but this test relies on timing and technique of swabbing and is limited by the sensitivity of the RT-PCR assays for SARS-CoV-2, which at least in part explains the heterogeneity of estimated secondary attack rates (SAR) in contacts of index cases, which have ranged from 4.6-90%. Many studies also limited testing to symptomatic contacts only. In contrast, serological studies have reported higher rates of SARS-CoV-2 infection than estimated through swabing. and there is growing evidence that children are as likely as adults to be infected with SARS-CoV-2 and develop a robust antibody response.

In London, England, COVID-19 cases began to increase rapidly in early March and peaked in midApril before declining to low numbers by the end of May 2020. Healthcare workers were disproportionately affected, with high rates of COVID-19, especially among clinical staff with direct patient contact. We hypothesised that children of healthcare workers were more likely to be