H1N1 E627K In India Increases Pandemic Concerns
Recombinomics Commentary 14:36
March 16, 2010

The swine flu virus isolated from the throat swab samples of three H1N1-infected patients at the National Institute of Virology (NIV) has shown a small genetic mutation in the polymerase 2 (PB2) gene

The above comments and additional media remarks strongly suggest that E627K has been detected in at least three patients in India.  Although there have previous reports of E627K in Shanghai and The Netherlands, the earlier reports were in the first and second waves in the northern hemisphere, when there was little selective pressure because wild type H1N1 was spreading rapidly.

However, at the start of the third wave, there is significantly more pressure because of the establishment of immunity to wild type pandemic H1N1 in a significant percentage of the target population.

E627K increases polymerase activity at lower temperatures and therefore favors increased replication in the mammalian upper respiratory tract.  All human flu since 1918 has had E627K, further supporting its selective advantage.  The presence of E627K in three patients signals transmission, and it is likely that E627K will become much more common in the upcoming weeks.

The start of a new wave in the northern hemisphere leads to increases in a range of genetic changes.  Increases in G158E, D225G/N and H274Y have been noted and such increases are likely to accelerate in the third wave in the northern hemisphere.

E627K can lead to higher levels in the upper respiratory tract and more efficient infections associated with higher viral loads.  An increase in viral load can significantly impact the course and severity of the infection. 

When H1N1 jumps species, as seen in pandemic H1N1, there are a series of adaptations that lead to more efficient replication and spread in the new host species.  E627K is a modification that is linked to efficient growth and spread in humans.

Thus, the report of E627K in three patients in India is significant and cause for concern.

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