Oct 30 (NHK) - NHK has learned the Wakayama prefectural government in western Japan says its survey found one in four people who tested positive for the coronavirus but showed no symptoms later developed pneumonia.
Wakayama is the only prefecture that has been hospitalizing all people who test positive. The local government surveyed 5,169 people who were admitted to hospital up until and including the fifth wave of infections in the country.
Of them, 1,199 showed no symptoms when virus tests were conducted. Among the people admitted to hospital with no symptoms, 331, or about a quarter of them, were later diagnosed with pneumonia. In this group, 76 developed moderate or serious symptoms requiring oxygen and 20 died.
Wakayama officials say the survey indicates that infected people with no symptoms may become ill rapidly. They call for creating a system to find changes in infected people's health condition at an early stage and respond to it quickly.
Nojiri Takako, who supervises the prefecture's anti-coronavirus measures, urged people without symptoms to remain on alert. The official also says it is important for public health centers and medical institutions to be involved in dealing with such people to prevent them from becoming seriously ill and stem the spread of infection.