Swine flu cases drop — seasonal flu a no-show

The pandemic H1N1 flu that killed thousands of people in recent months has sunk into a lull.

Cases of the H1N1 swine flu have dropped off around the country. But health officials say they’re waiting for the next wave to begin.
(Chart: Percentage of Visits for Influenza-like Illness (ILI) Reported by the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet)/CDC )

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H1N1 cases surged in the fall, the second wave to a pandemic that first appeared in spring of 2009. Now, the flu has fallen into a lull.

Stephen Ostroff is Pennsylvania’s director of epidemiology. He says previous pandemics produced a smaller third wave, which he expects to come later this winter.

Ostroff: The fact that this came at a funny time of year which was in the fall as opposed to the middle of winter gives it an opportunity to kind of show up once again at a time of the year where influenza transmission is still common.

Ostroff says that, unexpectedly, regular seasonal flu is also on hiatus.

Ostroff: The other factor that’s really sort of a wild card is what’s happening with seasonal influenza. And up to this point in Pennsylvania and elsewhere in the Unites States, we haven’t seen any. And this is at the time of year when we’d usually expect to start seeing a lot of seasonal influenza activity.

Ostroff says that exposure to swine flu may have given people immunity to seasonal flu, and help quell its spread.

Vaccine for H1N1 is widely available, and Ostroff encourages people to get it before the virus returns.

At a press conference today, Susan Walsh, New Jersey’s deputy health commissioner, said she expects the flu won’t stay at bay for long.

Walsh: It is probably likely that some of those seasonal flu is going to be around especially as the winter increases, that’s why we’re asking people to get both influenza shots.

Vaccines for both swine flu and seasonal flu are widely available.