Nature Medicine | Spoonful of Medicine

Waiting it out

mad hen.jpg
Blame the chicken
The lines are long, and people have been turned away in droves. Only the lucky and persistent—including the Obama girls—have got their swine flu shots in the US.

The vaccine is late, and in short supply—just at the US epidemic may be hitting its peak (see this ominous interactive map from the Wall Street Journal.)

But there is no shortage of blame: slow-growing viruses, chicken shortages, and, according to one opinion piece, higher doses of vaccine going to women than they may need. So, why not add another culprit to the mix: the lack of adjuvants. These are substances added to vaccines to increase their potency and decrease dosage.

The US is not using adjuvants in swine flu vaccines, whereas European regulators have approved them. As a consequence, each US citizen lucky enough to get a shot will be injected with 3 times as much vaccine material than people in Europe (15 vs. 3.75 micrograms).

But there are some subtleties. For instance, not all manufacturers in Europe are producing adjuvanted vaccines. Glaxo Smith Kline and Novartis, companies with large research enterprises devoted to adjuvants, have put them in their swine flu shots. But other companies, such as Baxter International, have not. European health authorities, it seems, have not figured out how to get adjuvants into the non-adjuvanted vaccine—something that can be done at the sight of administration. The US was prepared to spike its vaccines with adjuvant, ordering more than $500 million of the stuff from Novartis and GSK in case it was needed.

Another factor that could affect global supply is that European regulators this week recommended two shots of the vaccine, while most people in the US will get just one. It seems US authorities are content with the less-than-perfect protection afforded by one shot, while European regulators may be reaching for air-tight immunity.

Meanwhile, the US Food and Drug Administration has just approved a vaccine—cervarix, the shot against cervical cancer—with a new generation adjuvant. It’s the first adjuvant to hit US soil since alum, more than 60 years ago. The approval could signal a change in mindset at an agency with a reputation for extreme caution on vaccines—but it comes too late for the swine flu.

Some critics have charged the FDA with being asleep at the switch while European regulators developed plans over the last few years to put oil-in-water adjuvants into pandemic flu vaccine should they be needed. Europeans readied the safety data and set the stage for quick, systematic, approval (see my story on adjuvants in the September issue).

It’s not clear what factors went into the decision not to use adjuvants in the US. But the swine flu vaccine works fine without them, and when the decision was made, supply seemed assured. And just typing ‘vaccine adjuvants’ into Google will tell you how freaked out people can be about vaccine safety.

A few months ago, when swine flu vaccine manufacturing seemed on track, some health experts criticized the US for being a bad global citizen in deciding not to use adjuvants, because its extra needs could drain the world’s supply. But now the decision seems to be coming home to roost.


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    Annette Markus said:

    Seriously, why is the vaccine still produced in eggs? Influenza viruses can grow in tissue cultures, but progress in bioreactor development seems a-w-f-u-l-l-y s-l-o-w… Must be money reasons, but it’s hard to believe that gazillions of eggs would be cheaper than some big fermenters.