Paradigm Shift Intervention Monitoring
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Commentary
CDC Expands
H3N2v Tests To ILI Cases Without Swine Exposure
Recombinomics
Commentary 22:45
August 21, 2012
The above comments from a newly posted CDC document entitled “Interim Guidance for Enhanced Influenza Surveillance: Additional Specimen Collection for Detection of Influenza A (H3N2) Variant Virus Infections” are overdue but welcome. The number of cases at a given venue, such as the more than 200 symptomatic attendees at the Gallia Junior County Fair leaves little doubt that H3N2v is transmitting human to human. West Virginia has also detected three H3N2 cases in adjacent Mason County in additional attendees, while six H3N2 cases in Ashland, Kentucky, which is 40 miles from the Ohio and West Virginia cases, are likely additional H3N2v which have been misdiagnosed. These six cases are largely under the age of 5 and tested positive for influenza A. Misdiagnosis of H3N2v as seasonal H3N2 has been noted previously, and may have been increased by the lack of swine contact by the Kentucky children.
The CDC has been citing swine contact in cases who were tested because of swine contact, which is a circular argument that was been widely misinterpreted as evidence of swine to human transmission, which is not supported by the USDA data which has strong sub-clade discordance between H3N2pM in swine and H3N2v in humans. The swine sequences have the sub-clade that was circulating in humans last year, but was not detected in the 20 most recent H3N2v sequences, including 18 from 2012 (in Utah, Hawaii, Indiana, Ohio).
The above announcment is a first step in regaining testing balance, and the CDC should address its prior claims of swine to human support in the USDA data, which clearly does not exist.
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