TOKYO: Japan is likely to be experiencing the 10th wave of COVID-19 infections, as reported infection cases have increased for nine consecutive weeks, according to an infectious disease expert.

The spread is being driven by the highly contagious new variant JN.1. Norio Sugaya, visiting professor of infectious diseases at Keio University, has warned the public to take precautions.

In May last year, Japan lowered the status of COVID-19 under the infectious disease law to Class V, the same as seasonal influenza. The country also stopped counting all infected people and shifted to a monitoring method covering cases reported by about 5,000 chosen medical institutions nationwide.

According to the health ministry, the number of infected people reported per organization reached 12.23 in the week through Jan. 21, 1.4 times higher than the previous week. The expansion continued from late November last year.

In Ishikawa Prefecture, where many people are evacuated due to the Noto Peninsula earthquake Jan. 1 this year, the per-institution number stood at 14.33, also 1.4 times higher.

Behind the coronavirus resurgence are increasing infections with JN.1, which mutated from the BA.2.86 omicron variant.

The World Health Organization says that there have been no reports that JN.1 is more likely to cause severe symptoms than other variants. But it is likely that JN.1 evades the human immune system more easily and thus spreads fast, according to announcements by the WHO, the University of Tokyo’s Institute of Medical Science and others.

In Japan, the new variant is rapidly replacing others. According to the National Institute of Infectious Diseases, JN.1 accounted for about 20 pct, the largest share, of the 194 COVID-19 samples examined by private testing organizations from Jan. 1 to 7. The share is forecast to reach 43 pct early next month.

“JN.1 seems to be better able to evade immunity,” Sugaya said. “The current situation can be described as the 10th wave of infections, and the number of infected people is feared to rise further due to the spread of JN.1.”

In light of reports from abroad, Sugaya said that Japan is unlikely to see a sharp increase in the number of COVID-19 deaths due to the spread of JN.1. But he emphasized that elderly people in particular need to be careful because there is a risk of developing severe symptoms.

“The flu seems to have passed the season’s peak, but it is still spreading. I want the public to remain cautious, wearing face masks and washing hands,” Sugaya said.

JIJI Press