Those of us, who are prudent enough to get their yearly vaccination, are relatively safe[1]. Or at least somewhat safer than those who aren't vaccinated.
Still, an aberrant Influenza virus might become the next pandemic. With 'Aberrant' I mean those Influenza viruses that are not (yet) covered by your yearly vaccination: Influenza A(H1N1), Influenza A(H3N2), and Influenza B/Victoria lineage*.
Influenza A viruses are divided into subtypes. Influenza subtypes are named by their (simply increasing in number of discovery) hemagglutinin (HA or H) and neuraminidase (NA or N) proteins. To date, 18 different H's and 11 different N's have been found in nature. While more than 130 influenza A subtype combinations have been identified, primarily from wild birds, there are potentially many more influenza A subtype combinations given the propensity for virus 'reassortment'.
Influenza A virus subtypes and Influenza B virus lineages can be further broken down into different HA genetic 'clades' and even 'sub-clades'. And all of them can potentially evade the vaccine.
It is therefore exceptionally important to keep track of these viruses. And that is what I will do.
Here, I introduce a chart that follows the number of human infections and fatalities as a result of those aberrant Influenza viruses*.
* The Influenza B/Yamagata lineage might have become extinct in 2020|2021 as a result of COVID-19 pandemic measures[2]. As a consequence of this fortuitous effect, Influenza B/Yamagata lineage is not included in Influenza vaccines anymore.
* This chart only mentions cases from the WHO’s Western Pacific Region (WPR) as this part of the globe can be regarded as the primary 'breeding ground' for novel Influenza viruses.
[1] Deng et al: Repeated vaccination with homologous influenza hemagglutinin broadens human antibody responses to unmatched flu viruses in medRxiv - 2024
[2] Koutsakos et al: Influenza lineage extinction during the COVID-19 pandemic? in Nature Reviews. Microbiology - 2021. See here.
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