The Associated
Press
- A new study has found that giving a booster shot in addition
to the oral polio vaccine is the best way to ensure that babies
in Third World countries are protected from the virus.
In industrialized
countries, three doses of oral vaccine are 95 percent effective
in protecting children. But the rate in developing countries is
as low as 65 percent, perhaps because youngsters there are resistant
to the vaccine or the vaccine is not properly refrigerated.
In a study,
researchers gave either booster shots or extra doses of an oral
vaccine to 785 9-month-old babies in Oman who had already gotten
five doses of oral vaccine. Only the booster shots proved effective.
The booster
shots kept antibody levels high for at least six months, Dr. Roland
W. Sutter of the Centers for Disease Control and Prevention reported
in Thursday's New England Journal of Medicine.
The polio
vaccine works by spurring the immune system to make protective
antibodies. Polio shots contain dead polio virus; the oral vaccine
contains a live but weakened virus.
Although it
has been nine years since the last case of polio in the Western
Hemisphere, the virus is still found in 30 countries in South
Asia and sub-Saharan Africa.
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