The cruise ships were a great Petri dish and so far it is believed that asymptomatic patients comprise 15-20%, but more research is needed. https://www.niid.go

The cruise ships were a great Petri dish and so far it is believed that asymptomatic patients comprise 15-20%, but more research is needed. https://www.niid.go.jp/niid/en/2019-ncov-e/9417-covid-dp-fe-02.html https://www.niid.go.jp/niid/en/2019-ncov-e/9417-covid-dp-fe-...