Photo Credit PHIL
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In the wake of the publication of the Fouchier & Kawaoka studies (see here & here) - which suggest that the H5N1 virus may be only a few mutations away from being able to transmit among mammals – once again concerns over the possibility of a bird flu pandemic have taken center stage.
Despite its relative mildness, the 2009 H1N1 pandemic demonstrated the difficulty (read: impossibility) of creating, manufacturing, and rapidly deploying an emergency pandemic vaccine to billions of people in the face of a fast spreading influenza virus.
Were an H5N1 pandemic to break out today, even with small quantities of a vaccine already stockpiled, the vast majority of people around the world would not see a vaccine in anything less than six to twelve months.
And while the true CFR (Case Fatality Ratio) of the H5N1 virus remains disputed (see Revisiting The H5N1 CFR Debate), many researchers still believe it has the potential to be as deadly – or deadlier – than the 1918 Spanish Flu.
All of which as recently led to the resurfacing of a controversial, but potentially life-saving idea: the creation and distribution of a pre-pandemic vaccine.
While we’ve discussed this idea before, it was recently aired in the journal Science in an article called:
Influenza: Options to Improve Pandemic Preparation
Rino Rappuoli, Philip R. Dormitzer
While other solutions, including development of a `universal vaccine’, and improvements in our capacity to quickly produce and distribute vaccines were on their list, number one on their hit parade was the creation and distribution of a pre-pandemic H5 vaccine.
A pre-pandemic dose of an adjuvanted H5N1 vaccine – even if it were not an exact match to an emerging pandemic strain – is expected would blunt the impact of the H5N1 virus while the population waits for the arrival of a booster shot.
This idea is explored today in a Reuter’s story:
ANALYSIS-Bird flu vaccine now? More than a shot in the dark
As this article points out, an effective pre-pandemic vaccination program could take 3 to 5 years to conduct, and would cost billions of currently hard-to-find healthcare dollars.
One of the biggest obstacles would be the public’s reaction to accepting a vaccination against a virus that – as yet – does not routinely infect humans.
And no doubt, the anti-vaccine and internet conspiratorialists would have a field day with such a program.
This proposal, however, isn’t new.
We looked at this option in May of 2010 (see The Prime Of Our Lives), when the Journal Nature ran an opinion piece by Dr. Klaus Stohr, former head of the World Health Organization's global influenza program, supporting the idea of global pre-pandemic vaccination.
The problem is (aside from the not-insignificant costs, logistics, and difficulties gaining public acceptance) is predicting which influenza strain is likely to emerge next.
Few would have pegged the H1N1 virus – a cousin to one that had been circulating for decades – to show up as a pandemic virus in 2009.
Which means we could spend billions priming against an H5 pandemic, only to get blindsided by an H7 or H9 virus.
It’s a calculated risk, though many scientists would point out that an H5 pandemic – at least right now – seems to pose a greater risk simply due to its record of lethality in humans.
And in fact, this strategy was employed in Japan back in 2008, when their limited stockpile of H5N1 bird flu vaccine was about to expire.
They decided to `store it’ in the arms of healthcare and public safety workers, rather than pour it down the drain (see Japan Begins Pre-Pandemic Inoculation Of Health Care Workers). A similar program was launched in 2010 (see Taiwan Offers Public Bird Flu Vaccinations.)
Of course, we won’t know how well this little experiment works until an H5N1 pandemic breaks out, and recipients of this vaccine are shown to have fared better than those who weren’t `primed’.
But the idea is rooted in science.
In the summer of 2008 we saw a study, published in the of The Journal of Infectious Diseases, which showed that people who received an experimental H5N1 vaccine in Hong Kong 8 years before developed a strong immune response after receiving a single booster shot of a clade 1 H5N1 vaccine.
Influenza vaccines have an exceptionally good safety record, yet when millions of shots are given a small number of adverse reactions – some of them serious – are expected to occur.
When a clear and immediate viral threat is at hand, it is fairly easy to accept the risk-benefit equation presented by accepting a vaccine. But when no threat currently exists, one’s tolerance for risk – no matter how slight – tends to diminish.
Making a pre-pandemic jab a tough sell to an increasingly dubious public.
While the science makes sense (and yes, I’d probably avail myself of a shot were it made available), when you add up the costs, public relation concerns, and the sheer logistics of delivering a pre-pandemic shot to hundreds of millions (or even billions) of people, you have a formidable task.
One that, despite the potential benefits, governments don’t appear to be inclined to undertake right now.
