Asymptomatic COVID-19 carriers may be just as infectious as those displaying symptoms, a study accepted for publication in Nature found.
Researchers tested more than 70 percent of residents in a small Italian town that locked down in February due to COVID-19.
About 42.5 percent of residents with confirmed COVID-19 infections were asymptomatic. There was no statistically significant difference in asymptomatic and symptomatic patients' viral load, which offers a measure of infectivity.
The study's findings highlight the difficulty of controlling COVID-19's spread when so many people may not realize they have the virus. Study authors said a strong testing and tracing strategy can help identify these individuals and contain the pandemic.