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Flu shot failure shows need for a new formula

In hospitals across the country people are in intensive care units, some on respirators, close to death,  because of flu complications  — and many had their flu shot this year. 
Image: Michael Li gets a flu vaccination
The mismatch between the flu vaccine and the circulating virus means many people have gotten sick, even though they received the shot.Mark Lennihan / AP

Another year, another flu vaccine failure.

In hospitals across the country, people are in intensive care units — some on respirators close to death — because of complications of influenza. Many, if not most, had their flu shot this year. 

This information comes from my own admittedly unscientific survey of infectious disease specialists. It is hardly a surprise. The Centers for Disease Control and Prevention estimates that, on average, 36,000 Americans a year die from complications of influenza. In the past few weeks this has suddenly become a bad flu season.

The major factor in the intensifying epidemic is a strain called Bribane/10. It often causes severe disease, and to make matters much worse, this year’s flu vaccine doesn't protect against this strain.

The reason for the mismatch between the vaccine and circulating virus stems from the unbelievably complex and difficult task of making up every year’s flu vaccine a year in advance.

“Brisbane/10 was just not on our radar last year when were formulating the vaccine,” said Dr. Nancy Cox, head of the CDC’s influenza branch.

That's precisely why it's about time to try to tackle the flu threat in an entirely different way.

Dr. Michael Osterholm, head of the University of Minnesota’s Center for Infectious Disease Research and Policy in Minneapolis has called for a “Manhattan Project” to find a flu vaccine that does not need to be reformulated every year.

There seems to be little chance it will happen anytime soon. Some researchers are working on the problem, but President Bush’s recent budget veto cut $750 million from vaccine research.

Osterholm's center runs a news service which was among the first to report the problems with this year’s vaccine. He says many of his colleagues in public health were furious with him for calling attention to it

“They want to put their heads in the sand, instead of telling the public the truth,” he said. The fear is that, at a time when the nation finally had enough vaccine to go around — as opposed to the shortages of previous years — the public would lose more faith in flu vaccine. As a result, manufacturers would cut back on production, leading to shortages when we need vaccine in the future.

More art than science
One of the biggest challenges in warding off the flu is that the virus can mutate very rapidly.  That is why manufacturers must produce a new vaccine, and we must get a new shot every year.

There are no reliable ways of knowing how severe any season will be and which strains will predominate. “The saying in the business is, ‘if you have seen one flu season you have seen one flu season,’” explains Dr. John Schaffner, an infectious disease expert at Vanderbilt University in Nashville.

Every year scientists from the World Health Organization, the Food and Drug Administration and the CDC look at samples of viruses gathered around the world and try to determine which ones will dominate in the next year’s season. It takes most of the year to manufacture the vaccine in sufficient quantities and only three strains can go into each year’s vaccine. Identifying the ones that may dominate the next season is difficult enough — more an art than science, many admit.

It gets worse. The experts must pick strains that grow well in eggs where the vaccine is manufactured and generate antibodies when injected into ferrets, the lab animals used to test human influenza.

Given all that guess work, it is amazing that the experts are correct as often as they are. But the predictions could get even more difficult. The world’s growing population and the massive amounts of international air travel make it ever more easy for a strain that appears anywhere in the world to show up elsewhere very quickly.

Even worse, there is the threat of a pandemic, an outbreak of avian flu or some other strain of virus so different from what circulated before, from which no one has any immunity. We would be well served by having something better than the horse and buggy vaccine technology now in use.