The COVID-19 situation in Japan has magnified for nine consecutive weeks due to the spread of new mutant strains. The Ministry of Health, Labor, and Welfare reported a continuous increase in confirmed cases, leading some to speculate on the onset of the 10th wave. Experts emphasize the threat posed by highly contagious mutant strains and urge the public to remain vigilant and adhere to preventive measures.
In May 2023, Japan downgraded its COVID-19 prevention level to that of seasonal influenza, altering the reporting method. Results from around 5,000 designated medical institutions across Japan indicate a rising trend in reported cases, with an average of 12.23 patients per institution by the week ending January 21—1.4 times higher than the previous week and a consistent increase since late November 2023.
In Ishikawa Prefecture, where earthquake evacuees sought refuge, the average number rose to 14.33 per medical facility, a 1.4-fold increase from the previous week. The surge is attributed to the introduction of the new mutant strain JN.1, an evolved form of Omicron’s BA.2. The World Health Organization (WHO) notes JN.1’s potential for increased contagion due to improved immune escape capabilities, though it doesn’t necessarily lead to more severe illness.
Japan’s National Institute of Infectious Diseases found JN.1 accounted for 20% in a recent survey, estimating it to rise to 43% by early February. Norio Sugatani, an infectious diseases expert, warns of the higher immune escape potential of JN.1, suggesting it may spark a considerable increase in confirmed cases. Despite overseas reports indicating a less rapid rise in domestic deaths, Sugatani stresses the need for caution, particularly among the elderly. He encourages the ongoing practice of preventive measures, including mask-wearing and frequent handwashing, as influenza continues to prevail.
