Shot Protects Against Chickenpox After Exposure

Vaccination within 5 days prevents or lessens illness in those at risk, study finds

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En Español

TUESDAY, Jan. 26, 2010 (HealthDay News) -- There is good news for people who have never had chickenpox or received the vaccine but are exposed to the virus: vaccination within five days of exposure can significantly reduce the risk of illness, or at least make it less severe, Spanish researchers say.

The study, published in the January issue of the Pediatric Infectious Disease Journal, found that out of 67 people who received the varicella zoster vaccine within five days of exposure to chickenpox, only 22 got sick. That's about 62 percent fewer than would be expected to become ill with the disease. Based on past studies, 58 out of the 67 would be estimated to develop chickenpox.

The patients who did get chickenpox developed mild to moderate cases, suggesting that the vaccine is 79 percent effective in preventing moderate to severe disease. It didn't matter if those vaccinated were children or adults: the vaccine appeared to have the same effectiveness, the study authors noted in a news release from the journal's publisher.

"Available varicella vaccines administered within five days after exposure to chickenpox are effective in preventing chickenpox and highly effective in attenuating the disease," Dr. Maria Brotons and colleagues of Hospital Universitario Vall d'Hebron, Barcelona, stated in the news release.

Chickenpox often causes mild illness, but the virus can cause complications and scarring. Young children and teens are especially at risk of developing rare complications that can be serious.

More information

The Nemours Foundation has more on chickenpox.

SOURCE: Lippincott Williams & Wilkins, news release, January 2010

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