Despite the halving of the US's flu vaccine supply, there could be fewer deaths than normal this winter if people follow official advice, New Scientist's analysis suggests.
Last week the UK's Medicines and Healthcare Products Regulatory Agency suspended the licence of a factory in Liverpool owned by Chiron Vaccines. The suspension followed the discovery in August of the bacterium Serratia in some batches of flu vaccine.
The UK, which was relying on Chiron for only 10% of its supply, has been able to make up the shortfall, and the rest of Europe is mostly unaffected. But the US has been left with a huge deficit.
The US, which vaccinates a larger proportion of its population than any other country but Canada, had ordered a record 100 million doses this year. "We've gone from 20 million doses a year in the early 1990s to 87 million last year," says Bruce Gellin, head of the National Vaccine Program at the US Department of Health. At the start of October, health authorities were urging as many people as possible to get a flu shot.
Now the US finds itself with just 56 million doses, roughly half as many as expected. As the news hit the headlines, some Americans queued for hours for flu vaccinations, while Congress held hearings and accusations of mismanagement began to fly.
But even such a severe shortage will not necessarily mean more deaths. Two-thirds of the US's supply of flu vaccine usually goes to adults between 18 and 65. Yet 90% of deaths from flu occur in those over 65 years old. In the US, there are around 35 million people over 65. Moreover, in 2002, the most recent year for which figures are available, only 24 million of them got a flu shot.
That means the US could vaccinate just as many elderly people as in 2002 and still have 30 million doses of vaccine left over for the other groups for whom vaccinations are officially recommended: people with diseases such as asthma and, for the first time this year, some 10 million children under 2.
"If all doses go only to the target groups, we may have enough to cover them at past immunisation rates," says Kristin Nichol of the Veterans Administration Medical Centre in Minneapolis, a leading epidemiological expert on flu vaccination.
The Centers for Disease Control (CDC) is now urging healthy people under 65 not to get vaccinated, to ensure what vaccine there is goes to those most at risk. The impact on flu deaths this year will depend on how closely that advice is followed.
Many clinics are turning away healthy adults, as the CDC recommends, while the elderly rush to get their shots amid all the publicity. In fact, if more elderly people than usual get vaccinated as a result, there could actually be fewer flu deaths this winter.
A lot will depend on how virulent this season's flu strain turns out to be. The yearly death toll in the US varies from 17,000 to 51,000 depending on severity.
The problems with flu vaccine production this year are symptomatic of a wider ailment in the industry stemming from high production costs, static markets and low prices. Last December the US National Vaccine Advisory Committee recommended government purchasing guarantees and other means to ensure that more companies enter the vaccine market. At the time "significant, unprecedented and unanticipated" shortages, which had begun in 2000, were affecting 8 of the 11 routine childhood vaccinations.
"The vaccine industry will change," says Jaap Goudsmit, chief scientific officer of Crucell, a Dutch biotech firm that is making a new-generation flu vaccine with Aventis. "This sort of thing just cannot continue."
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article