According to collected reports, there have been very few cases of flu during the Covid-19 pandemic. This has led scientists to question, “Have some flu viruses gone extinct?”
While the Covid-19 pandemic has been extremely severe, flu cases have dropped to historic lows. Experts believe that wearing masks and implementing other preventive measures against the coronavirus have inadvertently been effective in reducing flu incidence.
Interestingly, there have been 2 types of flu viruses that have almost completely disappeared from any human cases over the past year. This means that no flu cases have been reported worldwide. Experts are still uncertain whether these types have gone extinct. However, local officials will consider additional factors before including flu virus strains in the seasonal flu vaccination list.
To explain which flu viruses may have gone extinct, we first need to understand how flu viruses are classified. According to the Centers for Disease Control and Prevention (CDC), there are 2 families of flu viruses that cause seasonal flu: Influenza A and Influenza B. Currently, H1N1 and H3N2 are the two types of flu that have been circulating among humans. However, each type of flu has its own distinct characteristics.
H1N1 and H3N2 are the two types of flu that have been circulating among humans.
Influenza B is not subdivided or divided into two lineages known as B/Yamagata and B/Victoria. A sublineage of H3N2 is referred to as 3c3.A. They have been reported to have not appeared since March 2020, similar to the B/Yamagata lineage, which is also no longer seen.
Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai, shared his thoughts on the B/Yamagata strain: “Just because no one has seen them doesn’t mean they have completely disappeared. However, this could also be a precursor to their return.”
The more diverse flu viruses are, the more dangerous and costly they become. Each year, scientists research and produce flu vaccines months in advance of flu season. A lower diversity of flu viruses means a smaller group of circulating viruses, leading to a greater ability to integrate multiple strains in a single vaccine dose.
The more diverse flu viruses are, the more dangerous and costly they become.
The H3N2 virus is a particularly diverse group that emerged before the Covid-19 pandemic, with its subgroups increasingly varying genetically. Therefore, a decrease in diversity for this flu type would be “wonderful.”
Webby warns that there may still be strains of the virus that exist even if we do not observe their presence. However, the significant decrease in flu cases this year may bring about some changes to the flu.
