Some Covid-19 Studies Are More Meaningful Than Others

New antibody tests are allowing researchers to begin to make more-informed estimates of how many people actually have Covid-19. They’re not perfect, though, and they’ve been saying greatly varying things about the spread and severity of the disease. Bloomberg Opinion columnists Justin Fox and Noah Smith — who, let’s be clear, are not epidemiologists, but have been reading a lot of epidemiology research lately — met online recently to discuss where things stand.

Justin Fox: Some early studies are showing that a lot more people have been infected with the new coronavirus than the confirmed-case numbers indicate. Testing of pregnant women in two Manhattan hospitals found that 15% had Covid-19, which if it were true today for the entire city's population would mean about 10 times more infections than confirmed cases. Testing for coronavirus antibodies in residents of Chelsea, Massachusetts, found that 30% were infected, which if true for the entire population would be about 15 times the confirmed cases.