One of the general assumptions we’ve formed about Covid-19 is that when someone is infected, they’re no longer contagious after two weeks—hence the recommended 14-day quarantine. But this isn’t necessarily the case.
Following the first appearance of symptoms, the vast majority of people are unlikely to be infectious for more than two weeks. For people who develop severe symptoms, that period extends to 21 days. Now, the Chinese government has determined that as many as five percent of Covid-19 cases have an incubation period longer than two weeks, and is taking action accordingly.
Their precedent may be one to follow. At NYU Shanghai, for example, local authorities recently issued a seven-day exclusion rule. Anyone returning to NYU Shanghai, a satellite campus of New York University, from overseas—even after a standard 14-day quarantine—cannot enter campus buildings for an additional seven days.
Originally published on Forbes (November 23, 2020)