Respiratory Viruses Surveillance Bulletin: Epidemiological Week 41

SARS-CoV-2 positivity has declined in the region and remains low in most countries (Figure 1). However, in Japan, positivity has consistently ranged between 20% and 30% over the past few weeks.

In several countries, including Japan and the Republic of Korea, the onset of the typical seasonal influenza activity period appears earlier than in previous years.

Multiple media sources have reported increased respiratory activity in several of these countries, consistent with the expected seasonal circulation of respiratory pathogens, albeit earlier than usual, including influenza viruses, respiratory syncytial virus (RSV), and other common respiratory viruses.

While there are also media reports of increased hospitalisations, these are proportionate to the overall rise in respiratory infections, with no evidence of increased severity.

The predominant circulating subtype is influenza A(H3N2) (Figure 2), marking a shift from A(H1N1)pdm09, which predominated during the previous winter season.