Commuters wear protective masks as they crowd after getting off the subway during rush hour in Seoul, South Korea.
People who have the coronavirus without developing symptoms appear to have similar levels of the virus in their noses and throats to people with mild symptoms, a study has found. However, this doesn’t necessarily mean they are as likely to spread covid-19 as those who are sick.
After much speculation early on in the pandemic, a growing body of evidence suggests people can pass on the coronavirus even if they don’t have any symptoms. But it still …