Wednesday, March 09, 2011

Nature: A Preemptive H2N2 Vaccine Strike?




# 5363



That’s the idea behind an article that appears (alas, behind a pay wall) in today’s Nature, where authors Gary J. Nabel,Chih-Jen Wei & Julie E. Ledgerwood  discuss the idea of possibly heading off the next pandemic by launching a preemptive strike  . .  .


. . .  against the H2N2 virus.


The article is called:


Vaccinate for the next H2N2 pandemic now


  • Gary J. Nabel, Chih-Jen Wei & Julie E. Ledgerwood

Nature Volume: 471, Pages: 157–158

Date published: (10 March 2011)

DOI: doi:10.1038/471157a
An old influenza strain still circulating in birds and swine could easily jump back to humans now that immunity to it has dropped, warn Gary J. Nabel and his colleagues.




While it hasn’t circulated in humans since it was supplanted by H3N2 in 1968, for eleven years – between 1957 and 1968 – the H2N2 Asian Flu virus was the king of the viral mountain (see below).


Flu Timeline 2010


H2N2 still circulates at low levels in birds, and swine.


But immunity in humans is pretty much non-existent for those under the age of 50, which some scientists fear leaves the world vulnerable to a new H2N2 pandemic.


We get more details from the BBC, after which I will return with more.


Call to vaccinate against possible H2N2 flu pandemic

By Dominic Hughes



H2N2 isn’t the only viable pandemic contender out there, of course. The H5N1 virus, along with the H7s, H9s and even H11s are all considered to have some degree of pandemic potential. 


What H2N2 has, that these others have not, is a recent track record of actually producing a pandemic. 


But whether that makes it any less of a long shot to spark the next pandemic is impossible to tell.



Last May (see The Prime Of Our Lives), 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 for a jab against a flu which isn’t currently a threat) 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.


Quite interestingly, friend and fellow flu blogger Scott McPherson broached the subject of H2N2 returning as a pandemic virus way back in 2007 in the following blog:


Will H2N3 reassortant prove Maurice Hilleman correct?

Posted on Wednesday, December 19, 2007


So the idea of H2N2 returning someday isn’t exactly new.


In just about every book, movie, or TV show about a deadly virus, valiant scientists cobble together some last-minute vaccine, produce it in quantity, and distribute it in the nick of time to save the world.


It is a grand idea, and a handy resolution for any disaster movie, but it suffers from one fatal flaw: 


We’ve neither the technology, manufacturing capacity, or the public health infrastructure to be able to produce and dispense a vaccine to billions of people in a matter of months.



Hardening the immune systems of billions of people against the next emerging pandemic strain could conceivably save millions of lives, and billions of dollars.


So the idea of deploying a vaccine to forestall the next pandemic years before it arrives is certainly intriguing  . . .   assuming the right strain can be selected.


But whether it is possible to sell that idea right now to a world where global economies are in recession, healthcare budgets are tight, and public trust in governments and science continues to ebb remains to be seen.



The hard truth is another pandemic is inevitable, and the next one may have a far greater impact than the last.  


And so solutions, even the difficult ones - like rolling out a pre-pandemic vaccine to billions of people - deserve public airing and consideration.

No comments: