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New anthrax vaccine has same makeup, more consistent doses

By Faith Bremner
Capital News Service

WASHINGTON - On the recommendation of the Institute of Medicine, the U.S. Department of Health and Human Services decided to seek a new type of anthrax vaccine, called a recombinant anthrax vaccine, for the nation's stockpile. This new vaccine is supposed to provide a more consistent dose of antibody-producing antigen than the current vaccine does.

VaxGen of Brisbane, Calif., is developing the new vaccine. BioPort Corp. has been producing the older version at its Lansing plant since 1970.

What's the difference between the vaccines?

Both vaccines work the same way. They consist of proteins from the anthrax bacteria, which cause the immune system to respond and make antibodies, and adjuvant, a chemical compound that stimulates the immune system.

Their differences lie in how they're manufactured. Through genetic engineering, the newer vaccine's anthrax proteins are highly purified and selected for their effectiveness, which gives the manufacturer consistency from one batch to the next. The anthrax proteins in the older vaccine are more variable, which leads to small inconsistencies in each batch.

Is one vaccine type more effective than the other?

In theory, they eventually should be equally effective at protecting humans against anthrax.

A 2002 Institute of Medicine study found that BioPort's vaccine is effective and safe.

VaxGen is still conducting clinical trials to determine whether its product is as effective as BioPort's.

The VaxGen vaccine has run into a problem that often happens with recombinant vaccines - its proteins are so pure that they fail to cause enough inflammation within the body to induce a high immune system response.

Why isn't BioPort manufacturing the new vaccine?

The company declined to bid on the contract because it did not want to pursue a technology that company officials say is not significantly better than the one they already use. Instead, they would like to develop vaccines that could be administered via a patch or a pill and that could be stored at room temperature.