Intensive COVID-19 Testing and Contact Tracing Needed for Schools to Reopen, Studies Indicate

By Amy Orciari Herman

Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

Schools might be able to reopen safely if COVID-19 testing and contact tracing are ramped up, according to two studies in The Lancet Child & Adolescent Health.

First, in a modeling study, researchers estimated potential SARS-CoV-2 transmission if U.K. students return to school either part-time or full-time in September, with one of three test-and-trace strategies (testing ranged from 18% to 87% of symptomatic people, and contact tracing ranged from 40% to 68% of contacts). The researchers found that without high levels of testing and contact tracing, a second wave of the pandemic would occur and peak in December with full-time return to school and in February 2021 with part-time return. However, this might be prevented: For example, if students returned full-time and 68% of COVID-19 contacts could be traced, then 75% of people with symptomatic infection would need to be tested (and positive cases would need to isolate for 14 days) to avoid a second wave. If just 40% of contacts could be traced, then 87% of symptomatic people would need to be tested.

In a second study, Australian researchers monitored nearly 1500 close contacts of 27 children or adults with COVID-19 who attended childcare centers or schools across New South Wales while infectious (within 24 hours before symptom onset). Contacts were expected to quarantine at home for 14 days. Among the 44% of contacts who underwent nucleic acid or antibody testing, just 18 secondary COVID-19 cases were identified, yielding a secondary attack rate of 1.2% Nearly three-fourths of the secondary cases came from one childcare center.

Commentators write, "Both studies give potential options for keeping schools open and show the clear importance of adequate contact tracing and testing. ... However, many questions remain, including whether there are age-related differences in susceptibility and the likelihood of transmission between children and adolescents."