The number of Americans who have been tested for COVID-19 is in the thousands. The number of South Koreans: nearly 200,000 people. The US has been noticeably slow in getting people tested for the virus. Marco Werman speaks with Michael Mina, an epidemiologist at the Harvard T. H. Chan School of Public Health, on the value of testing for the virus and what’s in it for the individual, as opposed to just the broader community.