A Japanese government survey conducted in December shows Tokyo had a 1.35 percent positivity rate for coronavirus antibodies. It also shows that the prefectures of Osaka, Miyagi, Aichi and Fukuoka had rates below one percent.
Antibodies are a type of blood protein produced after viral infection. Their presence in the blood suggests past infection.
The health ministry tested about 15,000 people aged 20 or older in Tokyo and the 4 prefectures.
The results, released on Tuesday, show the Tokyo antibody rate at 1.35 percent.
The rate was 0.71 percent in Aichi Prefecture; 0.69 percent in Osaka Prefecture, 0.42 percent in Fukuoka Prefecture and 0.14 percent in Miyagi Prefecture.
Ministry officials say the survey confirmed that many people had no antibodies. They say the rates are low compared to European countries and the US, and advised that people continue basic antivirus measures.