TUESDAY, June 2 (HealthDay News) -- The human papillomavirus (HPV) vaccine works for women aged 24 to 45 who aren't already infected by HPV, the virus that has been linked to cervical cancer and other cervical diseases.
That's the finding from Dr. Nubia Munoz, of the National Institute of Cancer in Bogota, Columbia, who noted that women's rising age at first marriage and increasing divorce rates have led to more widespread premarital intercourse and pairing with new sexual partners around middle age.
Their study included more than 3,200 women, aged 24 to 45, with no history of cervical disease or cancer or genital warts caused by HPV types 6, 11, 16 and 18. The women received either the quadrivalent HPV vaccine, which protects against the four HPV types, or a placebo at day one and months two and six of the study.
The women were followed for about 2.2 years and the researchers identified four cases of infection or disease in the vaccinated group, compared to 41 cases in the placebo group. That means the vaccine was 91 percent effective against all four virus strains.
When they looked at only HPV types 16 and 18, the researchers found four cases in the vaccine group and 23 in the placebo group, which means the vaccine was 83 percent effective against those two HPV types.
"Lower effectiveness detected in the mixed population (susceptible women and those who have already acquired HPV infection or HPV-associated disease) suggests that the public health effect of vaccinating women aged 25 to 45 years will be smaller than that recorded after vaccinating susceptible adolescents. This notion will be assessed in future cost-benefit analyses," the study authors wrote.
The findings appear online June 2 and in an upcoming print issue of The Lancet.
The U.S. National Cancer Institute has more about HPV vaccines.
SOURCE: The Lancet, news release, June 1, 2009
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