Friday, September 4, 2009

H1N1: Avoid "the boy who cried wolf" effect

From the LA Times blog:
Since the outbreak this spring of the novel H1N1, public health officials have treated the new so-called swine flu as if it were a replay of the devastating 1918 Spanish flu, which claimed tens of millions of victims and was particularly devastating to people who were otherwise young and healthy...

What’s wrong with preparing for the worst-case scenario? Plenty, Doshi writes. The SARS panic prompted involuntary quarantines, travel restrictions, and led to at least $18 billion in economic losses. In the end, the number of people affected by the response to the virus was much greater than the number of people infected by it.
The blog discusses a BMJ article by Peter Doshi, which notes:
... pandemic preparedness strategies have largely considered only type 1 (catastrophic) epidemics. Public health responses not calibrated to the threat may be perceived as alarmist, eroding the public trust and resulting in people ignoring important warnings when serious epidemics do occur.
Calibrating public health preparedness

Swine flu clinics have been arranged for public schools in Maine.  Governor Baldacci has declared a swine flu emergency.  (I have not yet learned what the implications are for Maine when such an emergency is declared, but it may trigger provisions of the Model State Emergency Health Powers Act, as passed by the legislature.

Sept. 8 Update: Governor Baldacci's office said he declared an emergency to protect school H1N1 vaccination clinics from liability.  But the federal government already protected them with a PREP Act Emergency Declaration in June.

The last time the US initiated a school immunization program was in 1962, when students lined up to swallow a pink drop of attenuated polio virus placed on a sugar cube.  The Sabin oral vaccine we received was quite effective.  But there continued to be reversions to virulence of Sabin's viruses (which may be shed in the stool for years after vaccination), and for more than a decade recently, the only polio cases in the US were due to viruses derived from vaccine strains.  As a result, Sabin's polio vaccines are no longer used in the US. 

This brings up two points.  First, why are we setting a precedent for school-based vaccinations for a relatively mild disease, when the US has managed well with its usual vaccination strategies over the last 47 years?  (Despite sensational media reports, only 12 healthy children have died after developing swine flu in the US, through August 8.  Most of these cases had secondary bacterial pneumonias.  Approximately 350 adults had swine flu-associated deaths during the same period.  The disease doesn't target children as strongly as the media made it appear.) 

Second, the Sabin saga demonstrates that adverse vaccine effects are difficult to predict in advance.  You simply cannot calibrate the risk from a new vaccine until it has been given to millions of people.

Just as the punishment should fit the crime, let's calibrate our response to swine flu to fit the degree of threat, based on the available data, keeping in mind the many unknowns and maintaining flexibility of response.

UPDATE Sept. 3:  President Obama on Tuesday requested an additional $2.7 billion "in emergency H1N1 flu funding to buy vaccines, antiviral drugs and to make other preparations for an immunization campaign in the fall," Roll Call reports (Dennis, 9/2). "The money is on top of $1.8 billion the administration earmarked in July for tackling the virus" and is part of funds that have already been appropriated, Reuters writes(9/3).

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