Rockville, Md. – Children and adults have similar risks of becoming infected with SARS-CoV-2, but a much larger proportion of children are asymptomatic, according to a report in the October 8 issue of JAMA Pediatrics. The results are based on the Coronavirus Household Evaluation and Respiratory Testing (C-HEaRT) study, which Abt Associates manages for the Centers for Disease Control and Prevention (CDC).
The C-HEaRT study followed 310 households with one or more children aged 0 to 17 years in New York City and selected counties in Utah. The study’s intensive surveillance approach included weekly systematic molecular testing of 1,236 participants for both asymptomatic and symptomatic SARS-CoV-2 infections and weekly questionnaires about symptoms. The study monitored SARS-CoV-2 from September 2020 through August 2021, though the article covered data only through mid-April 2021, the most active infection period before the Delta variant emerged in the U.S.
In an editorial in the journal, Dr. Flor M. Munoz of the Baylor College of Medicine said the study’s “clever approach” could be “a model for the timely implementation of infection and transmission studies in areas of disease activity in future outbreaks and pandemics.”
Among the findings:
- Children and adults had similar rates of infection, underscoring the need for rapid evaluation of efficacy and safety of COVID-19 vaccines for children and that other SARS-CoV-2 infection prevention strategies, such as handwashing, masking, and physical distancing, should target children in addition to adults
- Roughly half of the cases in children were asymptomatic, compared with 12 percent of the adult cases, highlighting the need for more research on transmission risk of asymptomatic cases
- Fever was an infrequent symptom among both children and adults, so the common practice of screening based on fever is likely to miss many cases
- In households with one or more infected individuals, the household infection risk was 52 percent, suggesting households remain a common transmission site.
The report noted several factors that may have led previous studies to underdetect cases among children. Most previous studies lacked systematic, longitudinal testing for both asymptomatic and symptomatic infections or relied on serologic markers of infection that may not always be present or sustained after asymptomatic infection. The C-HEaRT study avoided those pitfalls by capturing asymptomatic and unreported mild cases.
However, the report acknowledged the C-HEaRT study has its own limitations. Participants may have a more positive attitude toward science and public health than the general population and exhibit behavior more likely to reduce infection risk. Alerting participants to infections could change their behavior and reduce secondary transmission.
“These new findings about the prevalence of infections in children have important implications for group settings such as sports activities and school,” says C-HEaRT Abt Study Lead Jazmin Duque. “And COVID-19 vaccines for children 5 to 11 will be really important because infected children can transmit the virus to the most vulnerable populations, such as grandparents.” Duque added that the study proved at-home weekly testing of children is feasible since many families enjoyed participating in the study. “If families routinely test and stay home when positive, this will really help prevent the spread of COVID-19,” she said.
Abt’s C-HEaRT partners include the University of Utah School of Medicine and Columbia University’s Vagelos College of Physicians and Mailman School of Public Health. C-HEaRT is one of five studies under a COVID-19 contract that Abt manages for CDC. The others monitor first responders, healthcare workers, and essential frontline workers; pregnant women; older adults living in retirement venues; and hospitalized adults aged 50 and older.
About Abt Associates
Abt Associates is a global consulting and research firm that uses data and bold thinking to improve the quality of people’s lives. From combatting infectious disease and conducting rigorous program evaluations, to ensuring safe drinking water and promoting access to affordable housing—and more—we partner with clients and communities to tackle their most complex challenges. https://www.abtassociates.com