Prevalence of asymptomatic disease

An estimated 40–45% of people who test positive for SARS-CoV-2 do not have symptoms at the time of testing, according to a narrative review of 16 cohorts in the Annals of Internal Medicine. In four cohorts with longitudinal data, few of the asymptomatic patients (0–10%) went on to develop symptoms. But in one skilled nursing facility, 89% of initially asymptomatic patients became sick. The researchers say, “It is imperative that testing programs include those without symptoms.” They add, “The early data that we have assembled on the prevalence of asymptomatic SARS-CoV-2 infection suggest that this is a significant factor in the rapid progression of the COVID-19 pandemic.”

Review on asymptomatic disease in the Annals of Internal Medicine