(The Weather Network)
Some analyses show a divergence of subclade K from the vaccine strain of H3N2, although data on vaccine effectiveness in the real world is currently limited. If vaccine efficacy is reduced, we can expect more cases of flu. Monitoring this season is crucial to determine how much protection vaccines are providing.
However, even if a less vaccine-matched A/H3N2 virus becomes predominant this winter, immunisation is still expected to provide protection against severe illness and therefore remains an essential public health tool.
At present, the risk to the general population appears to be moderate, but higher for people who are more likely to develop severe disease (mainly those over 65, with other illnesses, pregnant women, or those who are immunocompromised).
(Graphic courtesy: The Weather Network/Canva)
Therefore, although subclade K of the A/H3N2 virus does not appear to be more virulent, the fact that the flu season has arrived a few weeks early and that the most prevalent strain is A/H3N2 suggests that this will be a more difficult season, with a higher number of hospitalisations and greater pressure on health services.
