LONDON (Reuters) - An oral vaccine packed into bacteria found in dairy products like milk and cheese protected mice from the anthrax bacteria, suggesting a pill could replace injections for humans, researchers said on Monday.

"Normally, you can't eat vaccines because the digestive process in the stomach destroys them, so vaccines are administered by needle," Todd Klaenhammer, a researcher at North Carolina State University in the United States who co-led the study, said in a statement.

"Using 'food grade' lactic acid bacteria as a vehicle provides a safe way of getting the vaccine into the small intestine without losing any of the drug's efficacy," he said.

The study, which included scientists from the U.S. Army Medical Research of Infectious Diseases, was published in the Proceedings of the National Academy of Sciences.

Anthrax is a fairly common bacteria whose spores can be used as a biological weapon. Usually it causes an easily treated skin lesion. But if inhaled, it can take hold quickly and by the time a person starts showing symptoms, it is usually too late for successful treatment with antibiotics.

Earlier this month, Human Genome Sciences Inc said it would provide an initial 20,000 doses of ABthrax, which fights anthrax infection, to the U.S. government. U.S. based Emergent BioSolutions also produces a vaccine.

But because most vaccines are proteins, they lose effect when the passing through the stomach. This means they require, sometimes numerous, injections to work, researchers said.

Klaenhammer and his team showed that once the vaccine was through the stomach and in the small intestine, it was able to bind to immune cells needed to trigger a response to protect against anthrax.

In their study, the oral vaccine worked about as well as a vaccine delivered by needle, the researchers said.

The next step is to look at whether the "good bacteria" can deliver other oral vaccines to provide immunity against a range of viruses and pathogens, they added.

"Can we make these generally recognized as safe lactic bacteria into a premier delivery system for vaccines and biotherapeutics?" Klaenhammer said. "That's the question we are now trying to answer."

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• Anthrax
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