Frequency of asymptomatic carriers of SARS-CoV-2 among children and adults after school reopening

Abstract

Background Children often develop an asymptomatic form of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), but it is debated if children are at higher risk than adults to be asymptomatic carriers of SARS-CoV-2, especially during the school reopening. The main aim of this study was to investigate the frequency of SARS-CoV-2 asymptomatic carriers in children and adults during the reopening of the schools in Milan, Italy. Methods We conducted a cross-sectional study at the pediatric and adult Emergency Department (ED) of the Ca' Granda Ospedale Maggiore Policlinico (Milan) between October 1 and 31, 2020, i.e. 3 weeks after the reopening of schools. Patients admitted to the ED short stay observation and without any sign or symptom consistent with a SARS-CoV-2 were eligible. These patients underwent a nasopharyngeal swab specimen for the detection of SARS-CoV-2. The odds ratio and its 95% confidence interval (CI) was calculated to assess the risk of asymptomatically carrying the SARS-CoV-2 infection in children and adults. Results A total of 69 (27 females, median age 8.7 years) children and 251 (107 females, median age 71 years) adults were enrolled. Pediatric and adult subjects tested positive for SARS-CoV-2 with a similar frequency (1/69 [1.4%] vs 4/251 [1.6%]). Children had an odds ratio to be a carrier of 0.91 (CI 0.02– 9.38) compared to adults. Conclusions The frequency of asymptomatic SARS-CoV-2 carriers was similar among children and adults. Considering the emerging diffusion of new SARS-CoV-2 variants, the asymptomatic spread of SARS-CoV-2 infection among children and adults should be monitored.

Disappearance of Seasonal Respiratory Viruses in Children Under Two Years Old During COVID-19 Pandemic: A Monocentric Retrospective Study in Milan, Italy

“…Among the various NPI, many countries closed schools and kindergartens during lockdowns, resulting in substantial reduction in social interactions. To-date, the effect of school closure is seemingly associated with beneficial effects on overall mortality per week, ( 8 ) and has probably different effects depending on the age of children attending schools ( 9 , 10 ). There is a general consensus on NPI effectiveness in containing SARS-CoV-2, even if before the COVID-19 pandemic evidence supporting isolate NPIs was low ( 11 ).…”

Early evidence of SARS-CoV-2 in Milan, Jan-Feb 2020

“…Yet, a previous report of our group conducted during the first lockdown in the same EDs has shown a SARS-CoV-2 infection prevalence of 1.2% in asymptomatic children and of 9.2% in a comparable adult population [ 14 ]. A similar study conducted during the school re-opening in the same setting was not able to find a higher prevalence of asymptomatic carriers among children as compared to adults [ 15 ]. Finally, it has been reported that children infected with SARS-CoV-2 might present several clinical presentations and therefore some potential cases could have been excluded in our analysis [ 16 ].…”

Analytical Performance of Quantitative DiaSorin Liaison SARS-COV-2 Antigen Test for the Asymptomatic Population

“…In addition, the pediatric population was included in the analysis despite it was suggested that children could be facilitators in the spread of SARS-CoV2 infection because many affected children might be asymptomatic (15) but several studies demonstrated that the frequency of asymptomatic SARS-CoV-2 carriers was similar among children and adults (16).…”