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H1N1 Genetic Changes in RBD Raise Pandemic Concerns

Recombinomics Commentary 19:09

November 8, 2009



Right now we know that many clinical specimens and viruses have been sent to one of the WHO collaborating centres for further study. We don't know the results of those studies, and it will probably take a couple of days for the full analysis of those viruses to be available.

The above comments are from Thursday's WHO press conference and raise concerns that the sequences from Ukraine (see map ) have small changes which may include receptor binding domain changes. Several such changes have been seen in previously published sequences and position 225 has been of concern. That position was linked to the establishment of amantadine resistance in seasonal H3N2 and raises concerns that such a change in swine H1N1 could make the virus more virulent. In seasonal flu, the change was D225N, and that change is in at least three swine flu sequences, including two from fatal cases in San Paulo, Brazil collected in August (see list here ).The same position has also changed to D225G, which was also found in other fatal cases in San Paulo, Brazil. It is also in more recent (September) isolates from China (see list here ).The new polymorphism most widely reported in sequences in Genbank is D225E, which is common in recent sequences from Italy (see list here ).Thus, similar changes in sequences from Ukraine would be of most interest, and such changes have not been ruled out by WHO statements thus far.The release of these sequences from Ukraine is now overdue , and these delays increase pandemic concerns.