In February of 2015, in India’s H1N1 Outbreak, we looked at the persistent media reports of unusually severe H1N1 flu activity on the Indian subcontinent, and the insistence by India’s National Institute of Virology (NIV) and their National Centre for Disease Control (NCDC) that there were No mutations in H1N1.
A few weeks later, in MIT: Genetic Changes In A 2014 Indian H1N1pdm09 Virus, we saw analysis of at least one flu isolate collected in 2014 that researchers said contained `amino acid changes linked to enhanced virulence and are potentially antigenically distinct from the current vaccine containing 2009 (Cal0709) H1N1 viral hemagglutinin.
The entire report/commentary – which emphasizes the need for more robust and timely influenza surveillance and sequencing data - can be accessed at: Influenza Surveillance: 2014–2015 H1N1 “Swine”-Derived Influenza Viruses from India.
Fast forward to today, and the ECDC's Eurosurveillance has done just that.
They've published an analysis of sequencing data from H1N1pdm09 isolates gathered in India during the first half of 2015. One that not only finds the rapidly rising Genotype 6B present but provides evidence of additional mutations as well.
This study also references the MIT study mentioned above. I've only excerpted a small piece, so follow the link to read it in its entirety.
Received:11 December 2015; Accepted:04 February 2016
The tendency is to become complacent with seasonal flu, and to worry only about the novel flu strains. But the virulence of seasonal flu is not constant, and it is always possible for an old and familiar flu to learn new tricks.
The changes observed in this study - and those recently reported by the Russians (see Week 5 Epi Report) - are intriguing and beg further investigation and study. But it remains to be seen how much of an effect they will actually have on the virulence and future impact of the H1N1pdm09 virus.