Low-Dose Polio Vaccine Effective

Giving just one-fifth the usual dose of the polio vaccine may protect babies against the virus nearly as well as a full dose, as long as it is injected just beneath the skin, according to a recent study. The study tested a needle-free jet injector made by Bioject Medical Technologies to deliver the vaccine beneath the skin in 373 children at ages 2 months, 4 months and 6 months. Blood tests showed that more than 95 percent of the infants mounted an effective immune response against polio. And, while babies who got a lower dose had fewer antibodies against polio, researchers said that shouldn’t be a problem.

The findings could reduce the cost of immunization, an important consideration in developing countries, some of which have had trouble containing the paralytic disease. The injectable vaccine costs about $3 per dose, whereas the oral polio vaccine is much cheaper, at about 15 cents, but it contains a weakened virus that can mutate and sometimes cause polio in patients or when it gets into sewage. Therefore, health experts now favor the injectable vaccine. “If we can do one-fifth the dose, we can at least get it down to $1, so we are getting into the neighborhood of a price that may be affordable for developing countries in the future,” says Dr. Roland Sutter of the World Health Organization.