Even though the economic and social disruption caused by the COVID-19 was devastating, the pandemic may have led to the extinction of one of the four main strains of influenza virus that infect humans seasonally.
According to a report by The Wall Street Journal, labs across the world have not reported the presence of the influenza B Yamagata lineage, one of the four strains, for the past one year while uploading their findings on the international database GISAID.
Why is it a big deal?
Infection with influenza B Yamagata virus results in a quarter of the flu burden every year, Nature reported. If the strain goes extinct, then it opens opportunities for scientists to improve the availability and effectiveness of flu vaccines, which currently protect against all four strains. Without the Yamagata strain, vaccine makers can make a three-strain vaccine or introduce protection against another influenza variant.
The composition of the flu vaccine is reconsidered twice a year by a World Health Organization (WHO) committee. However, the final decision on the vaccines is taken by individual countries based on the recommendation of the WHO.
"If it's gone, it's a big deal,” The Wall Street Journal quoted Marios Koutsakos, lead author of the study reported in Nature, as saying.
Why it disappeared
There are many reasons that could have led to the disappearance of the Yamagata strain. The restrictions imposed to curtail the spread of the COVID-19 infections such as social distancing measures and lockdown also helped reduce the spread of flu infections. According to scientists, this has narrowed the genetic diversity of not just the Yamagata but all flu strains.
Also, the Yamagata is more vulnerable to extinction as it evolves more slowly than the other influenza B strain, say scientists.
Is the present data enough?
The study by Koutsakos and his colleagues mostly drew their research data from GISAID. However, another database tracking flu called the FluNet, which is run by the WHO, reported 46 Yamagata cases this year. Other labs that test for flu viruses have in the meantime shifted their focus on COVID-19 testing.
"Until we can get back to some normal type of surveillance, I think it would be difficult to be sure that it’s gone," Ian Barr, from the Doherty Institute in Melbourne, told The Wall Street Journal.
In its most recent meeting in September, the WHO committee did not consider omitting Yamagata from the four-strain flu vaccine. According to WHO, Yamagata has not disappeared as yet as a few cases have been reported. It will take scientists another year to confirm if the Yamagata has gone extinct.