Recombinomics Commentary 18:45
March 7, 2012
"State health officials say today that lab tests confirm that two of the members of a Calvert County family who died early this week of severe respiratory illness had Influenza H3, a strain of the flu that has been going around this season".
The above comments confirm the Recombinomics commentary published this morning on the H3 sero-type of the HA from the fatal Calvert County, Maryland cluster. However it is unlikely to be the “strain” of flu that has been going around this season.
Recombinomics called the Calvert County Health Department as well as the Maryland Department of Health and Mental Hygiene, and the US CDC to get a clarification on the testing that led to the report that the influenza A was seasonal flu, since the CDC has reported an explosion of H3N2 low reactors in the week 7 and week 8 FluView reports. The antigen characterization data indicated an new H3 had replaced the H3N2 strain that had been circulating earlier this season.
The CDC did not comment on this explosion and therefore it was unclear if the low reactors were a drift variant of the current seasonal H3N2 vaccine target, Perth/16, or were widespread H3N2v, which would also generate a low reactor result.
Moreover, the CDC PCR test distributed to state labs can identify H3N2v under ideal conditions, but most confirmed H3N2v cases gave negative, inconclusive, or seasonal H3 results, and H3N2v was confirmed by CDC sequencing.
The cluster in Maryland was determined to be H3 by the Maryland state lab, which was used for this morning’s announcement by Calvert County. Media at the Maryland state lab suggested I e-mail the specific testing questions, and also noted that the best source of information would be the CDC, who had already been asked via cell phone and e-mail about testing and the relationship between the H3 result generated by the Maryland state lab and the low reactors reported by the CDC, which may be H3N2v.
As of this commentary, neither agency has responded to the e-mailed questions, and the relationship between the H3 in the death cluster, the low reactors reported by the CDC, and H3N2v remains unclear, but the likelihood that the H3 “strain” in the Maryland death cluster matches the seasonal H3N2 dominant in the US in 2011 and early 2012 is extremely small.