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Commentary
WHO H1N1 Pandemic Alert - Rapid Spread of D225N
Recombinomics
Commentary 09:10
April 26, 2011
Since the beginning of 2011, in the region of the Americas, there have been significant outbreaks of influenza A (H1N1) 2009, that while geographically limited, have generated a significant demand on health services.
For instance, there have been outbreaks in Ecuador (January 2011), Mexico and Venezuela (March 2011). In the past three weeks (SE 13-15), the Dominican Republic’s National Influenza Centre has detected an increase in the positive samples of influenza A(H1N1) 2009. In the last month, other sporadic detections have occurred in Cuba, Colombia, Honduras, Jamaica and El Salvador.
The above comments are from the Week 12 regional update by the WHO Pan American Health Organization (first paragraph) issued on April 6, 2011, followed by comments in the pandemic alert issued two weeks later.
Although the April 6 report cites no evidence of “mutations that confer greater virulence” the title of deposited sequences is “Detection of D222N substitution in Pandemic Influenza A (H1N1)Virus in Chihuahua, Mexico” clearly signaling concern about D225N (D222N in H1 numbering). D225N was in one of the first three sequences and in one of the next five sequences from the Chihuahua sub-clade (which also had D225G). Anecdotal reports indicate D225N is in at least five more unreleased sequences from Chihuahua and is associated with severe and fatal cases.
The rapid spread of this sub-clade with D225N in collections from the upper respiratory tract of severe and fatal cases has led to the WHO pandemic, alert which includes the following recommendation:
It is recommended that all of the countries activate their National Preparedness Plans for the pandemic and follow the WHO and PAHO recommendations.
This alert, coupled with earlier reports of a precursor sub-clade in vaccinated patients, has raised concerns that the vaccination efforts in the above countries, as well as further efforts in South American countries, will have limited success, because current vaccines and those in production for the 2011/2012 season target a 2009 isolate, A/California/07/2009.
Release of the sequences with D225N in Mexico, sequences from severe and fatal cases in the countries cited above, as well as El Paso, Texas, where pneumonia and influenza deaths are at record levels, would be useful.
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