About 40 percent with confirmed COVID-19 are asymptomatic

(HealthDay)—The percentage of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is 0.25 and 40.50 percent among individuals undergoing testing and those with confirmed COVID-19, respectively, according to a review published online Dec. 14 in JAMA Network Open.

Qiuyue Ma, Ph.D., from Peking University in Beijing, and colleagues examined the percentage of asymptomatic infections among individuals undergoing testing and those with confirmed COVID-19 (tested population and confirmed population, respectively) in a meta-analysis of 95 unique studies covering 29,776,306 individuals undergoing testing.

The researchers found that among the tested population, the pooled percentage of asymptomatic infections was 0.25 percent, which was higher among nursing home residents or staff, air or cruise travelers, and pregnant women (4.52, 2.02, and 2.34 percent, respectively). Among the confirmed population, the pooled percentage of asymptomatic infections was 40.50 percent, which was higher among pregnant women, air or cruise travelers, and nursing home residents and staff (54.11, 52.91, and 47.53 percent, respectively).

"The high percentage of asymptomatic infections highlights the potential transmission risk of asymptomatic infections in communities," the authors write. "Screening for asymptomatic infection is required, especially for countries and regions that have successfully controlled SARS-CoV-2."