COVID-19 Carriers 'Most Infectious Earlier On'

BBC News reports that a new study suggests people are most likely to pass on COVID-19 within the first five days of having symptoms, with "live" virus detected up to nine days after manifestation of symptoms. The study in Lancet Microbe reviewed 79 global studies on COVID-19, involving symptomatic people in hospitals who had already tested positive for the pathogen. Scientists could identify and replicate viable virus from throat samples taken up to nine days after infections began, and the amount of viral RNA particles in the throat samples peaked at the time symptoms started or within five days. Moreover, inactive viral RNA fragments continued to show up in nose and throat samples for up to 17 days after symptoms began, on average. However, no viable replicating virus was found after nine days, meaning most people were unlikely to still be highly contagious past that point. "People really need to be supported to make sure they isolate as soon as they get symptoms, however mild," advised the University of St. Andrews' Muge Cevik. "By the time some people get the results of swabs, they may be past their most infectious phase."