BBC: New flu virus mutation could see worst season in a decade.
https://www.bbc.com/news/articles/c2dr8gzdz1wo
A seasonal flu virus suddenly mutated in the summer. Seven mutations appeared in a strain of H3N2 seasonal flu and led to a ”fast increase” in reports of the mutated virus. Exactly what the mutations are doing is still being explored, but they are probably helping the virus to evade some of the immunity we have built up over years of flu infections and vaccines.
Seasonal flu usually has an R number of around 1.2, while the early estimate for this year is 1.4, says Prof Lewis.
So very roughly, if 100 people had flu, they would pass it to 120 in a typical year, and 140 this year.
In a typical flu season, around one-in-five of us get infected, but that could be higher this year.
H3 is always a hotter virus, it’s a nastier virus, it’s more impactful on the population.
It is worth remembering that some of us will get flu and develop no symptoms at all, while others get a sudden fever, body aches and exhaustion – but the virus can be deadly in older and more vulnerable groups.
Nobody knows for certain what will happen in the coming months.
This year’s vaccine is not a perfect match to the mutated virus but this is ”absolutely the most important year” to get vaccinated!!
Science Media Centre:
The current circulating influenza A(H3N2) virus acquired 7 new mutations over the summer, which means the virus is quite different to the A(H3N2) strain included in this year’s vaccine (vaccine strains are selected in February for the Northern hemisphere winter season). It also means that the virus could have changed sufficiently to escape the immunity that have been built up from previous infections and vaccinations.
The new variant, known as ”Subclade K,” is part of the H3N2 parent group, or a type of Flu A.
Bengt Rahms blogg 