Most people infected with the novel coronavirus will show symptoms within five days, and almost everyone will be symptomatic by 12, according to a new study by American researchers that examines the outbreak’s spread in China over the past few months.
The finding suggests the 14-day quarantine imposed by Israel and other nations for those who had contact with infected people is the correct length.
But, the authors warn, the virus is contagious before the symptoms appear, a key factor in the difficulty authorities in China and elsewhere have had in containing the pathogen, despite quarantine measures imposed by many governments.
“If somebody is in their incubation period [before symptoms appear], that is the window when somebody who’s already been infected can walk into the country and not be detected by symptom-based surveillance,” Johns Hopkins Bloomberg School of Public Health associate professor of epidemiology Justin Lessler, the author of the study, told CNN.
The research was published Monday in the journal Annals of Internal Medicine.
The five-day incubation period was discovered when Lessler examined over 180 coronavirus cases from areas without the pathogen in individuals who had just arrived from the disease’s early epicenter in Wuhan, China.
Examining that spread in the earliest days of the outbreak, when transmission was moving almost exclusively from Wuhan outward, allowed Lessler to set good estimates for the moment of infection — the time spent in Wuhan — and then to track the amount of time it took for the traveler to show symptoms. Most were symptomatic by five days. Only in the rarest cases did the incubation period last longer than 12.
“We have sort of a narrow window at the beginning of the epidemic to really tease out what’s going,” Lessler told CNN this week. “If it’s everywhere, you don’t know where people got infected.” READ MORE
