COVID-19 Delta variant outpacing vaccine impact as daily cases top 10,000 in Japan

TOKYO -- With the Japan-wide daily new coronavirus case count topping 10,000 for the first time on July 29 despite Tokyo being two weeks into a state of emergency, and with states of emergency set to be declared for the capital's neighbors as well as Osaka Prefecture, the question can be asked: Why can't Japan bring the coronavirus crisis under control?

The government has taken initiatives to accelerate vaccinations against COVID-19, but the number of infections is increasing nationwide at an even faster pace, propelled by the Delta variant of the virus.

Although a state of emergency was declared in Tokyo on July 12, the number of people in downtown areas at night, especially in the capital where coronavirus cases are surging, has not decreased as much as the government had hoped. The highly infectious Delta strain is spreading where there is contact between people, mainly at eateries. As the declaration is failing to stop people from going out, experts are struggling to come up with alternative measures.

Tokyo and its three neighboring prefectures of Saitama, Chiba and Kanagawa account for about 60% of Japan's new coronavirus cases. According to estimates by the National Institute of Infectious Diseases (NIID), the proportion of Delta variant infection among new cases in each of the three prefectures was around 30% at the end of June, but had reached 70% by mid-July.

The Delta variant is said to be about 1.3 times more infectious than the Alpha strain, which was prevalent in Japan this past spring. NIID director Takaji Wakita explained, "The replacement with the Delta variant is proceeding, and infections are spreading like never before."

Meanwhile, 70% of people aged 65 and over have had their second vaccination, with shots continuing, and the impact is beginning to show. In Tokyo, the percentage of hospitalized COVID-19 patients aged 60 and older, which was 70% in February and March, dropped to 20-29% by July. The percentage of newly infected people aged 65 and over topped 20% in March, but dropped to 2.9% between July 20 and 26, indicating that the vaccine is doing its work.

However, infections are growing among people in their 20s and 30, who engage in a wide range of activities. Wakita pointed out, "It's clear that the number of infected and severely ill people is decreasing thanks to progress in inoculations of elderly people, but we're still a long way off for the entire population," suggesting that the current overall vaccination level is having a limited effect on the spread of the Delta strain.

Experts have not yet devised an effective breakwater against the Delta variant wave, and appear stuck. A public health expert said, "We can't estimate the infection peak. A slight decrease in the number of people going out will not help reduce Delta variant case numbers."

The number of patients recuperating at home is increasing, especially in Tokyo. The capital must prevent the multiple deaths among this group that struck western Japan's Kansai region in the spring. An infectious disease expert told the Mainichi Shimbun, "People may lack a sense of crisis unless the health care system collapses, resulting in many patients without hospital beds and thus deaths. But at that point, it's too late (to instill that understanding)."

(Japanese original by Ryosuke Abe, Hidenori Yazawa and Natsuko Ishida, Lifestyle and Medical News Department)