Asymptomatic individuals less likely to infect others; symptomatic cases more likely to infect others before symptom onset
MONDAY, Jan. 25, 2021 (HealthDay News) — Children and adolescents are less susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but are more infectious than older adults within households, according to a study published online Jan. 18 in The Lancet Infectious Diseases.
Fang Li, from the Wuhan Center for Disease Control and Prevention in China, and colleagues conducted a retrospective cohort study involving the households of all laboratory-confirmed or clinically confirmed COVID-19 cases and laboratory-confirmed asymptomatic SARS-CoV-2 infections identified between Dec. 2, 2019, and April 18, 2020.
A total of 27,101 households were identified, with 29,578 primary cases and 57,581 household contacts. The researchers found that when assuming a mean incubation period of five days and maximum infectious period of 22 days, the secondary attack rate was an estimated 15.6 percent. Compared with other age groups, those aged 60 years or older were at a higher risk for infection with SARS-CoV-2. Infants aged 0 to 1 years were significantly more likely to be infected than children aged 2 to 5 and 6 to 12 years (odds ratios, 2.20 and 1.53, respectively). Compared with adults aged 60 years or older, children and adolescents aged younger than 20 years were more likely to infect others given the same exposure time (odds ratio, 1.58). Compared with symptomatic cases, asymptomatic cases were less likely to infect others (odds ratio, 0.21). Symptomatic cases were more likely to infect others before versus after symptom onset (odds ratio, 1.42).
“These findings have implications for devising interventions for blocking household transmission of SARS-CoV-2, such as timely vaccination of eligible children once resources become available,” the authors write.
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