2011/12 influenza season – news on the cusp.

Two recent public health stories worth watching.   Last week, US reported on a swine reassortment on the H3N2 strain that was crossing into humans.  Three children in one day care in Iowa.   The variant had been identified about a dozen times previously and half dozen times this influenza year.  Whether this is signal of a potential new human to human transmissible variant is perhaps too early, however influenza watchers are likely beginning to raise cautionary flags. US announcement of H3N2 reassortment

In a much less publicized scenario, a US researcher has done genetic manipulation of the currently circulating H5N1 avian influenza such that it develops transmissibility between ferrets.  Ferrets you wonder?   Turns out ferrets are reasonably good influenza model for humans. The story got more attention because of the potential efforts of Homeland Security to block the publication of the findings as a potential threat to national security than for the actual risk that the study engendered.

Beyond the national paranoia related to bioterrorism, why the legitimate concern about the study findings?  For those that have kept an eye on this disease since 2000, you would be aware that it continues to spread globally WHO avian influenza page with the most recorded activity in 2011 in Egypt.  Some caution in interpreting the statistics in that not all countries are monitoring for H5N1, and predominately only severe cases are likely being tested.  The notable characteristic of avian influenza remains its almost 60% human mortality rate amongst confirmed cases.  So if the virus developed the ability to transmit between human, it would be a potential nightmare.  

The real issues around the avian influenza scenario clouded the pH1N1 planning as pandemic planning has been working from an assumption of much higher mortality and severity of illness than was manifest in the “milder” version of pH1N1.

Overall influenza activity globally has been lower than average so far this year.  The heralding of an long term care outbreak of H3N2 in Alberta combined with the reassortment identification in the US should put everyone on alert and push for the final efforts to provide vaccine protection to as many as possible.

In the midst of preparing for the disease season, there are always questions about the vaccine.  The question that needs to be posed, is that has the wider spread use of the vaccine already impacted the natural course of annual circulation such that we are reaping the benefits of much lower deaths and morbidity?  Perhaps an insidious form of herd immunity, and the resultant apathy towards the illness may be our greatest threat. 

Watching the false starts, the various influenza offenses and corresponding human defences manouveurs can be almost as exciting as a Grey Cup, and just as nerve-wracking.  For those active in public health, it is far from a spectator sport.