New research published in the Annals of Internal Medicine has cast a clear light on the median incubation period of the COVID-19 coronavirus. The researchers examined news reports about the spread of the virus outside of China as well as interviewed people outside of China who became infected with the disease, and from that extrapolated the time frame the coronavirus is likely to infect someone without a person showing symptoms.
The researchers found that the coronavirus is likely to have a median incubation period of 5.1 days before a person starts showing symptoms of the disease. And by 11.5 days after infection, 97% of people will have shown symptoms. The 5.1 day median incubation period puts COVID-19 in line with median incubation periods for other viruses like SARS.
The longer a virus’s median incubation period is, the more likely that virus is to spread as those infected with it have no idea they have the disease, so are more likely to continue to go about their normal everyday interactions with people.
As the research shows, when it comes to COVID-19, people could be walking around with the coronavirus and pass it on to others for at least five days without showing symptoms—and some individuals could host the virus for as many as 11 days before they show any symptoms. Given this 5- to 11-day timeline, the researchers conclude that a 14-day quarantine period initiated by many governments for those potentially affected is a reasonable one.