Osaka and Hyogo prefectures are again experiencing a steep surge in the number of novel coronavirus infections, causing many experts to warn that daily new infections in a fourth wave may double those of the third wave.
Their concerns reflect the situation in Britain where a variant accelerated the spread of infections.
At the peak of the third wave, the daily number of newly infected people was 654 in Osaka Prefecture on Jan. 8 and 324 in Hyogo Prefecture on Jan. 9. Doubling these peak figures would mean 1,300 new cases in one day in Osaka and 600 in Hyogo.
In Osaka Prefecture, the average number of new infection cases in the seven days to March 30 increased sharply to 2.2 times that of the previous seven-day period.
The Osaka prefectural government has estimated that if this average continues to double in the seven days from March 31, the number is estimated to be 891 cases on Friday.
The greatest concern is the spread of variants that are said to be more infectious than the conventional type.
According to the Health, Labor and Welfare Ministry, Hyogo Prefecture had the highest cumulative number of people infected with variants at 181 as of March 30, followed by Osaka Prefecture at 130. Among the U.K., South African and Brazilian variants confirmed in Japan, the U.K. variant accounts for all cases in both prefectures.
The latest situation regarding variants is believed to be partly due to the fact that young people have become more active in the prefectures where the state of emergency was lifted ahead of schedule at the end of February.
According to Mitsuyoshi Urashima, a professor of preventive medicine at The Jikei University School of Medicine, a mutated virus appeared in Britain last September. Within about three months, it accounted for about 60% of the infection cases in a region including London.
In response, a lockdown was imposed in some areas, but the number of infected people more than doubled in three weeks.
“It has been about three months since the U.K. variant was confirmed in Japan, and it is believed to have been becoming the main cause of new infections in Osaka and Hyogo prefectures,” said Urashima. “It would not be surprising if a similar spread of infection, like that seen in Britain, occurs in Japan.”
Toshio Takatorige, a professor of public health at Kansai University, added, “The number of infections could be estimated to be 1.5 times or even up to double that of the third wave.”
The ministry has asked prefectural governments to review their medical systems in case the number of infections doubles, such as by securing hospital beds for COVID-19 patients.
Koji Wada, a professor of public health at the International University of Health and Welfare, stressed the need to devise the next move in case there are no tangible effects from the priority measures.
These measures to prevent the spread of the disease allow governors to take actions similar to ones implemented during a state of emergency.