Children as Likely as Adults to Be Infected by Coronavirus, Chinese Study Suggests

By Reuters Staff

May 08, 2020

NEW YORK (Reuters Health) - Children are as likely as adults to develop COVID-19, according to a study of Chinese patients that contradicts other findings.

Most current transmission estimates have come from sources in which incomplete capture of infections and cases might have produced biased estimates, Dr. Justin Lessler of Johns Hopkins Bloomberg School of Public Health, in Baltimore, Maryland, and colleagues note in The Lancet Infectious Diseases.

To help avoid these pitfalls, the researchers used data from the Shenzhen Center for Disease Control and Prevention "for which the mode of surveillance (ie, symptom-based versus contact-based) was sufficiently documented and RT-PCR testing was nearly universal," they note. Between January and February, 391 SARS-CoV-2 cases and 1,286 close contacts were identified.

Cases were older than the general population (mean age, 45 years) and balanced between males and females. Most (91%) were of mild or moderate clinical severity at initial assessment and 77% were detected through symptom-based surveillance.

"Attack rates were similar across all age categories of infected contacts," the researchers note, "although we observed some indication of elevated attack rates in older age groups. Notably, the rate of infection in children younger than 10 years (7.4%) was similar to the population average (6.6%)."

As of February 22, 2020, three cases had died and 225 had recovered after a median time of 21 days. Cases were isolated on average for 4.6 days after developing symptoms but contact tracing reduced this by 1.9 days.

Compared with other close contacts, household contacts were at significantly higher risk of infection (odds ratio, 6.27). This was also true of those traveling with a case (OR, 7.06).

The household secondary attack rate, which was calculated as the proportion of household contacts (those sharing a room, apartment, or other sleeping arrangement) who were later confirmed to have SARS-CoV-2 infection, was 11.2%.

"We provide a key piece of evidence supporting intensive contact tracing and highlighting that children might be an important target for interventions aimed at reducing transmission, even if they do not get sick," the researchers say.

In an accompanying editorial, Drs. Kaiyuan Sun and Cecile Viboud of the National Institutes of Health, in Bethesda, Maryland, conclude, "Building on the SARS-CoV-2 experience in Shenzhen and other settings, we contend that enhanced case finding and contact tracing should be part of the long-term response to this pandemic - this can get us most of the way towards control."

Dr. Lessler did not respond to requests for comments.

SOURCE: and The Lancet Infectious Diseases, online April 27, 2020.