Dining without masks quadruples COVID-19 infection risk, survey shows

Japan's Prime Minister Fumio Kishida speaks during a question and answer session at the lower house of parliament in Tokyo on October 11, 2021. (Photo by Philip FONG / AFP)

japantimes– The risk of novel coronavirus infection for people who remove their face masks as soon as they take seats for dining with others is four times that for those who keep their masks on except when eating or drinking, according to a recent survey.

The survey was conducted by the National Institute of Infectious Diseases amid mounting concerns that new infection cases could surge again if an increasing number of people dined with friends or others after the government lifted its COVID-19 state of emergency at the end of last month.


Motoi Suzuki, who heads the NIID’s Infectious Disease Surveillance Center, called on people to “avoid high-risk activities, and only eat and drink with family members or in a small group.”

The survey, released last week, covered a total of 753 adults who visited five medical institutions with facilities for outpatients with fever in Tokyo between June and July. They were asked about their records of activity in the two weeks before exhibiting their symptoms. None of the patients had received COVID-19 vaccines, and 257 of them, or 34.1%, tested positive for the virus.

The infection risk for those who kept their masks on except when eating or drinking during dining with other people was almost the same as that for those who had no such opportunities, according to the survey. But the risk was 3.92 times higher for people who removed their face masks as soon as they were seated or did not wear masks during dining events.

The risk was 1.87 times for people who stayed at restaurants or bars for two hours or longer. Dining sessions involving alcoholic drinks raised the infection risk to 2.18 times.

The infection risk was 1.5 times higher for those who dined in a group of five or more than for those who did so with up to four people.

People who dined out alone did not see a rise in the infection risk.

NIID chief Takaji Wakita has urged people dining with others to have such events in a small group, limit the sessions to up to two hours and keep masks on in order to prevent infections.