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Commentary
H1N1 D225E Converted
to D225G in Egypt
Recombinomics
Commentary 19:28
February 16, 2010
However, A/Egypt-Vacsera/138/2009 also had G716A, which converted D225E to D225G. Reports of these conversions are becoming increasingly common and raise concerns that D225G is offering a selective advantage. Recent conversions have been seen in Japan, Italy, Norway, Sweden, and Spain.
Position 225 in pandemic H1N1 is hyper-variable. The conversion of the position to D225E is widespread, especially in Europe. In some countries, like Italy, the frequency of D225E is approaching 50% of deposited sequences, suggesting this change offers significant selection advantage. Although fatal cases with D225E have been reported, the countries with high levels of D225E do not have unusually high levels of fatalities.
However, in other countries like Ukraine and Russia, other position 225 changes (D225G and D225N) are more common and are strongly associated with fatal cases. Although the clade in Ukraine and Russia has the highest reported frequency of D225G/N, the same change is found on different sub-clades in different countries, including the death cluster at Duke Medical Center in North Carolina.
One of the Ukraine isolates was antigenically characterized by Mill Hill and was designated a low reactor, raising concerns that this change would be under positive selection pressure in patients previously infected with wild type H1N1 or those who had been vaccinated with the killed vaccine.
Consequently, a new wave may have a markedly higher frequency of D225G or D225N leading to a significant increase in severe and fatal H1N1 cases.
More sequence data on recent severe and fatal H1N1 cases would be useful.
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