A Cancer Vaccine That's 100% Effective?

A major study of Gardasil, an experimental human papillomavirus vaccine developed by Merck, has shown that the vaccine prevented 100% of HPV-related cervical cancer among the 10,559 women studied. None of the sexually active women who received three injections of the vaccine over six months developed cervical cancer or precancerous lesions, compared to 21 women receiving a placebo who did develop the conditions. A single dose of the vaccine was shown to be 97% effective. Cervical cancer is an AIDS-defining condition in HIV-positive women and the number 2 cause of cancer deaths among women in the United States. Merck hopes to have Gardasil on the market in 2006. A study reported in the November issue of HIV Plus showed that women with advanced HIV disease do not benefit as much from surgery to remove HPV-related cervical lesions, a precursor to cervical cancer, as women with higher CD4-cell counts; a CD4-cell count below 200 resulted in a ninefold increase in the odds of persistent or recurring intraepithelial neoplasia.