10.28.2009

H1N1 vaccine: adjuvants, thimerosal, and chicken eggs

Why You Can't Get the Swine Flu Vaccine

Excerpt:

Though the swine flu is widespread in 46 states many Americans are still waiting to get their vaccines. The Obama administration blames the shortage on manufacturing delays at the five firms making these products. But production issues only explain part of the shortfall. Also to blame are a series of policy decisions that reflect our extreme caution when it comes to these products.

From a regulatory standpoint, vaccines are unique in many ways. Since we distribute them widely to otherwise healthy people, they deserve careful oversight. But right now we are shunning new, superior vaccine science by being overly cautious.

On Saturday, when President Obama declared the outbreak a national emergency, he enabled the suspension of federal rules in order to speed the distribution of treatments. Yet less than half the projected vaccine has been actually shipped. Supply is far below the government's estimate of 40 million ready vaccines by November.

The first fateful policy decision, made last spring, was to forgo vaccine additives—called adjuvants—that activate the immune system and make shots more potent. Adjuvants allow a smaller supply of vaccine stock to be stretched across more doses. These adjuvants are included in H1N1 vaccines world-wide, but not in the U.S.

Why do adjuvants matter? An adjuvanted H1N1 vaccine being used in Europe contains 3.75 micrograms of vaccine stock. The same vaccine in the U.S., without the adjuvant, requires 15 micrograms of vaccine for equal potency. If we used adjuvants, we could have had four times the number of shots with the same raw material.

The second cautious decision was to require that the H1N1 vaccine be a single shot. The government demanded single-dose syringes because they contain smaller amounts of thimerosal than multi-dose vials. This mercury-containing vaccine preservative continues to stir concern it can trigger childhood autism, even though this has been firmly disproven.

The third policy decision was to stick for too long with a proven, but slow process for making flu shots that uses chicken eggs to grow the raw vaccine material. Shots can be made much faster using mammalian cells to grow vaccine, and this process is already being used in Europe. The cell-based vaccines are unlikely to be approved in the U.S. Our precaution when it comes to vaccines means we don't easily embrace novel technologies, even if the Europeans would part with some of their limited supply.


Comment: Interesting!

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