Writing in the lead article of this week's issue of The Lancet, Harper and her fellow authors said the vaccine has the potential to greatly reduce deaths from cervical cancer, one of the leading causes of cancer mortality among women worldwide. The vaccine is targeted to immunize against two different types of high risk Human Papillomavirus (HPV-16 and HPV-18) that cause an estimated 70 percent of cervical cancer cases.
HPV is a commonly occurring infection, transmitted by skin to skin contact, most commonly through normal sexual interactions. Although most cases of HPV resolve themselves through natural immunity, a percentage of cases will progress to cervical cancer. Currently, an estimated 280,000 women die from cervical cancer each year, most of them in the developing world. Of the 500,000 cases of cervical cancer diagnosed annually, 70 percent are attributed to infection from HPV-16 and18. The five year prevalence of cervical cancer worldwide in other words, the number of women in any five year period of time with cervical cancer is 1.4 million.
In the blinded, randomized trial of 1,113 women from throughout the U.S., Canada, and Brazil, participants received 3 doses of the experimental vaccine or a placebo over 6 months. At 27 months of follow-up, the vaccine showed an extremely high rate of efficacy, the authors write. In those women who completed the protocol receiving all three shots and participating in all scheduled testing and follow-up the vaccine was 100 percent effective against persistent HPV16/18 infections.
Significantly, the efficacy was only slightly reduced for those women who did not fully comply with the protocol re
Contact: Deborah Kimbell
Dartmouth Medical School