May 6, 2009

A "Flu Wave" Should be Named an "Influenza Tsunami"

update written by Avram L. Nemetz, M.D. Medical Director

The official WHO Stage Six still is ahead of us, but a certified pandemic is certainly coming, caused by the emergent Influenza A H1N1 virus which is beginning to circle the globe.

The CDC has withdrawn its recommendation that schools in the U.S. should be closed when a case of influenza is confirmed. This represents both capitulation to the pandemic (it is now part of our daily reality), and realization by relieved officials that, at the moment, the disease is not causing hospitalizations and deaths in high numbers.

We are told a second wave of flu may come harder in the fall. But what does this mean?

Imagine an earthquake beneath the Indian Ocean. Tectonic plates shift, and a wall of displaced water sweeps across the globe, swamping low-lying areas in its path, causing warnings to go up as far east as Hawaii and California.

Now imagine a new genetic shift in an influenza virus popping up in Mexico. Waves of infected people fan out from its origin and sweep around the globe. Well-studied pandemics in the 20th Century-the 1918 Spanish Flu, the 1957 Asian Flu, and the 1968 Hong Kong Flu-came in three waves,

with each wave corresponding to a tsunami of water fanning across the ocean and sweeping entirely around the world first once...and then twice...and then a third time. (This would be the time to imagine a colorful animated graphic of a flu wave sweeping around the world over and over.) Each subsequent wave hits those people who managed to stay dry on the previous pass. If you are infected by H1N1 on the first wave, you will be immune to the second and third.

If this model holds true, there is time to plan for the fall. Vaccines against the new virus will not yet be available. Anti-viral medications remain effective to date and still in good supply, and manufacturers should have time to ramp up production. Business continuity plans typically anticipate a 30-40% absentee rate at the peak of a flu pandemic, even a "mild" one.

But what we should be planning for is not a flu wave. It's an influenza tsunami.