He said the samplings from Tokyo and Osaka, where there were many confirmed cases, and Miyagi, where there were few, are expected to shed light on the antibody prevalence for the general population. The existence of antibodies for the coronavirus in the blood indicates the person has been infected. The tests will be conducted on about 3,000 randomly selected adults in each prefecture. Officials will take their blood samples after obtaining consent. The health ministry hopes to utilize the test results for measures to prevent future infections.