Dec 02, 2009

The Limits of Testing

As the H1N1 vaccine was rushed into service we were repeatedly assured that it had been adequately tested. In fact, H1N1 vaccine was so similar to previous flu vaccines that the experts were confident it would be every bit as safe and effective. Now we learn:

Researchers from the University of Missouri have uncovered evidence that taking over-the-counter pain relievers, like aspirin and Tylenol, can reduce the effectiveness of the vaccine because they inhibit the normal function of enzymes that help regulate the immune system. —Scientificblogging

This has always been the problem with testing vaccines and other pharmaceuticals: they can not possibly test for all the variations that any population presents. Much as researchers try to account for differences in lifestyle and diet, humans are too complex with too many constantly shifting variables to be able to say that a specific chemical reaction in Joe will perfectly replicate in Mary.

So now, after millions of people have already been vaccinated, we find that it may not have helped any of those taking aspirin, Tylenol and other common pain relievers, which, in over-dosed America, amounts to just about everyone.

“If you’re taking aspirin regularly, which many people do for cardiovascular treatment, or acetaminophen (Tylenol) for pain and fever and get a flu shot, there is a good chance that you won’t have a good antibody response,” said Charles Brown, associate professor of veterinary pathobiology in the MU College of Veterinary Medicine.
“These drugs block the enzyme COX-1, which works in tissues throughout the body. We have found that if you block COX-1, you might be decreasing the amount of antibodies your body is producing, and you need high amounts of antibodies to be protected.”

The only real testing of this and any other vaccine is in live populations. Give it to the people and see what happens.

If that’s the medicine folks want, go for it. Just don’t force anyone to participate.

Michael Sky | CommonHealth