200 H3N2v Cases In Gallia County Ohio
August 10, 2012
The following update is currently available from Gerald E. Vallee, MD, Gallia County Health Commissioner, in regard to H3N2v virus:
There have been 200 suspected cases reported; 69 of those tested positive for Influenza A using the rapid flu test. Representative samples of the suspected cases have been sent for further testing.
There are currently 4 confirmed cases of H3N2v in Gallia County. All individuals had direct contact with swine at fairs.
The above comments from the Gallia County Health Department in Ohio provide insight on the relationship between the number of H3N2v cases and the number of confirmed cases. Earlier reports cited 62 cases confirmed by the influenza A rapid test, which suggested more than 150 cases were tested.
The above update increases the number of influenza A confirmed cases to 69, but as noted in the August 9 CDC telebriefing, seasonal influenza levels in the United States are low, so most state lab confirmed cases with be H3N2v, especially when linked to an outbreak at an agricultural fair.
Thus, it is likely that the 200 symptomatic cases were H3N2v infected, although CDC confirmation is lagging and only four confirmed cases from Gallia County have been reported and included in the CDC update. However, the CDC has ceded H3N2v confirmation to the state labs, so the number of “confirmed” cases is expected to increase significantly in today’s MMWR as well as future updates by state labs as well as the upcoming Friday updates by the CDC.
However, as seen in the above outbreak associated with the Gallia Junior County fair, many infected cases will not be tested, and the number of “confirmed” cases will significantly undercount large outbreaks.