Data suggests an asymptomatic infection rate of 17%
rather than the estimated 80%


In a study that synthesized research on asymptomatic cases and transmission rates screened 2,454 articles and included 13 low risk-of-bias studies from seven countries that tested 21,708 at-risk people. Diagnoses in all studies was confirmed using a real-time reverse transcriptase–polymerase chain reaction test.

The study concluded:
The relative risk of asymptomatic transmission was 42% lower than that for symptomatic transmission
The 1 in 6 estimate of the prevalence of asymptomatic COVID-19 cases and asymptomatic transmission rates is lower than those of many previously publicized studies
Further robust epidemiological evidence is urgently needed, including in subpopulations such as children, to better understand how asymptomatic cases contribute to the pandemic

At a Glance

17 %
The rate of asymptomatic COVID-19 presentation is ~17%
42 %
Relative risk of asymptomatic transmission is 42% lower than for symptomatic
80 %
Earlier estimates that 80% of infections are asymptomatic were too high