H1N1 Activity Now Widespread in US South

And no state remains unaffected.

The CDC advises, however, that heightened H1N1 activity does not reflect the severity of disease. At least 99% of all subtyped influenza virus samples (n = 1402) are the 2009 H1N1 virus.

Also according to CDC data, the in-hospital death ratio associated with influenza-like illness (ILI), as of September 19, was 0.093 (mortality rate, 9.3%). US deaths include 49 children.

Multiplying the US hospitalization ratio for April 15 to July 24 (0.114) by the CDC's latest in-hospital death ratio for ILI provides a case-fatality ratio of 0.0106 (mortality rate, ~1%). However, a Harvard epidemiologist recently estimated the H1N1 death rate to be considerably lower—from 0.007% to 0.045%.

Vaccines for the 2009 H1N1 virus are expected to be available next month (that is, in a few days), with the nasal-spray vaccine preceding the shot vaccine in the US marketplace. Candidates for the nasal vaccine are nonpregnant persons 2-49 years of age.

Newly released results from a national survey (N = 1678), performed by the University of Michigan in August, revealed that a minority of parents plan to have their children vaccinated against the pandemic H1N1 virus. (The CDC currently recommends that all individuals from 6 months to 24 years of age undergo H1N1 [swine flu] vaccination.) Surveyed parents reported that they are more likely to have their children receive the seasonal influenza vaccination.

Parents' perception of the risks associated with H1N1 flu were closely linked to the likelihood of opting for the vaccine. Notably Hispanic parents were more likely to report their intention of having their children undergo vaccination—possibly because they perceive a higher threat from the disease than non-Hispanic parents. For instance, Hispanic parents may be more aware of the recent history of H1N1 disease in Mexico.