The government on Thursday disputed the claim made in a US study that the swine flu virus may have acquired mutations and said that the strain mentioned in it has "no relevance" to the 2015 outbreak.
National Institute of Virology (NIV) in Pune, which is under the government's Indian Council of Medical Research (ICMR), said that the strain analyzed in the publication and the data of the original H1N1 virus available with it "did not" show any of these mutations.
Massachusetts Institute of Technology (MIT) had yesterday released a study which said that the swine flu virus may have acquired mutations that make it "more severe and infectious" than previously circulating H1N1 strains.
"Our experts have carefully examined the findings mentioned in the above-mentioned publication. We found that the strain analyzed in the said publication and the sequence data of the original 'H1N1 virus A/India/6427/2014' as available with NIV did not show any of these mutations," an official statement said.
NIV said that it had recently analyzed six full genomes, which also suggests "absence" of such mutations.
The MIT study was conducted by Ram Sasisekharan, the Alfred H Caspary Professor of Biological Engineering at MIT and the paper's senior author, and Kannan Tharakaraman, a research scientist in MIT's Department of Biological Engineering.
"Subsequent report on antigenic/genetic analysis of H1N1 virus by CDC/WHO as communicated to NIV also did not report any oseltamivir resistance or any other genetic changes in HA genes that could be virulent markers.
"The genetic analysis of the HA gene of the H1N1 isolates from the present 2015 outbreak do not show any such mutations as mentioned in the above publication," it said.
NIV said that the observation is based on HA gene sequence analyzed for the H1N1 virus 2014 taken from a database and not from actual virus isolates from the current 2015 outbreak.
It said that the official statement was being issued so that the public has the correct information and does not get confused with the "incorrect conclusion" published in the publication.
The MIT researchers claimed that the recent Indian strains carry new mutations in the hemagglutinin protein that are known to make the virus more virulent.
The study said that in the past two years, genetic sequence information of the flu-virus protein hemagglutinin from only two influenza strains from India has been deposited into publicly available influenza databases which makes it difficult to determine exactly which strain is causing the new outbreak and how it differs from previous strains.
Meanwhile, in New Delhi, Health Ministry officials said they will take up the issue with ICMR since the latter has been maintaining till now that there has not been any mutation.
According to the Union Health Ministry data, as of March 10, as many as 1,587 people have died due to swine flu while the number of those infected in the country was 27,886.