Scientists at MIT have related that their assessment of current strains of influenza, especially the H3N2 strains, which are endemic in birds and pigs, are very similar to the 1968 strain of 1958 that killed almost one million people worldwide.
More worrisome is their statement that the vaccine produced now to contrast flu pandemics might not have much effect on these strains, as they are still in animals only.
Their call then is for the inclusion of these strains in the vaccine preparations that are made yearly ahead of flu seasons peaks, in order to create a preventive immune response in the case of their passage through the zoonotic barrier.
Because many of these strains have never circulated in the general population, there is no immunity against them, and the immune system does not recognize them, leading to the most severe symptoms in the infected subjects.
Some strains of the H3N2 viruses have been circulating in the human population since 1968, so that there is a partial recognition in the human body of the virus, and that they might make them less deadly.
But the problem now is that some of those strains that are in animals now have undergone significant antigenic shifts, or DNA reassortment, and may have mutated sufficiently to not be recognized by a human immune system.
In fact a geospecific study of existing animal strains of H3N2 resulted in a tally of 581 strains that have an antigenic indeces of more 49% and glycan attachment patterns, which facilitate the attachment of the virus to human respiratory tract tissue. Of these, 32 were swine strain and 549 avian.
When tested against antibodies that had been exposed to the H3N2 strains that are not in circulation and have not crossed the zoonotic barrier yet, they found, as they expected, that they did not recognize and react to the virus.
Next, the team is targeting H5 strains for testing.
Source : MNT 5.10.13
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