# 1397
The idea of inoculating a nation's population against a possible H5N1 pandemic has been attractive enough that several governments have already acquired large stockpiles of prepandemic vaccine.
The problems of using such a vaccine are not minor, however. First this article, then some discussion.
WHO says mass bird flu vaccinations not necessary
21 minutes ago
GENEVA (AFP) — The World Health Organisation (WHO) said Friday there was no need for a massive vaccine campaign against the bird flu virus (H5N1) because it has not been proven that it would become a pandemic.
"There is no evidence available that would say that we should begin vaccinating populations across the board with H5N1 at this point in order to prevent a pandemic because it is not known what may cause a pandemic," WHO Assistant Director General David Heymann told reporters.
H5N1, which has caused 209 deaths out 340 afflicted since 2003, is not the only virus that could start a flu pandemic, he added. Other viruses, such as H5, H7 or H9, pose the same threat, he said.
Heymann said many countries are considering a widespread vaccination campaign as part of a 'first protection' barrier, which would act as an insurance plan for the population.
However, he recalled that the swine flu vaccinations in 1976 in the United States had a lot of side effects.
"So a country would have to weight whether or not that insurance policy of getting a lower level of immunity against a virus which could cause a pandemic is as important as the side effect which might occur from that vaccine," he said.
Earlier this month WHO responded to the case of a father and son in China dying from H5N1 earlier this month. There were three possible explanations for the father-son case: either they were infected by the same animal, by transmission between them, or by exposure to two different infected animals.
The deadly H5N1 strain has passed from human to human only in very rare cases but scientists fear that such transmission could become more efficient and widespread through mutation, causing a global pandemic.
Proponents of prophylactic inoculations would point out that once a pandemic begins, it would be difficult, perhaps even impossible, to distribute a vaccine quick enough to do much good. Most vaccines require two doses, a month apart, to confer immunity.
By the time a population could be immunized twice, many would already have been exposed to the virus. In many ways, if you have a pre-pandemic vaccine, it's a case of either using it before a pandemic starts . . .or risk losing much of its benefits.
The timing of when you give a pre-pandemic vaccine has always been a bit murky. Give it too soon and the effects of the vaccine eventually wear off. A vaccine given in 2008 wouldn't have much protective effects in 2009.
Vaccines also have a limited shelf life. After a couple of years, they begin to lose effectiveness. What then? Do you destroy millions of dollars of vaccine, or do you consider deploying it in order to buy another six or twelve months of in-the-body `protection'?
And of course, a vaccine made from an older clade of the virus may not prove very protective against a newer strain of the H5N1 virus. And there is also the real possibility that the next pandemic could arise from a completely different influenza.
Complicating matters, memories of the 1976 Swine Flu debacle still run strong, and fears of side effects and lawsuits are another deterrent.
Despite these downsides, many nations are actively pursuing a pre-pandemic vaccine.
Switzerland has reportedly purchased 8 million doses of pre-pandemic vaccine, enough to inoculate their entire citizenry. Denmark, it was widely reported last January, ordered in enough pre-pandemic vaccine for half of their population. And in Australia, there has been talk of inoculating their entire nation.
New Zealand recently announced they had enough pre-pandemic vaccine on hand for 100,000 essential workers, and the UK is exploring the purchase of large quantities of vaccine.
While the WHO has never endorsed the idea, obviously there are a good many nations that view having a pre-pandemic vaccine as being a matter of national security.
The big question remains, however.
Even if you purchase a pre-pandemic vaccine, when do you pull the trigger and deploy it?
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