TOKYO -- A number of schools across Japan have been closed due to mass infections of seasonal influenza. The unseasonal outbreaks are thought to have been caused by the recategorization of COVID-19 as a "category 5" disease under the Infectious Disease Control Law, along with the relaxation of infection control measures.
Some experts have warned that the number of flu vaccinations has fallen since the outbreak of COVID-19, and general immunity against the flu has weakened.
