From ABC News' Chief Medical Editor Dr. Timothy Johnson:
Today's issue of the Journal of the American Medical Association (JAMA) contains two articles ? and an excellent editorial ? addressing the question of whether the benefits of the Gardasil vaccine outweigh its risks. The vaccine is designed to prevent infection by two strains of the HPV (Human Papilloma Virus); these strains are said to account for about 70% of cervical cancer cases. The vaccine is now recommended for 11-12 year old girls before they become sexually active. For the first time in my career, I cannot recommend a vaccine for its intended population ? in this case, young girls. Therefore I am going to say that any parent considering this vaccine for their daughter should read the editorial in JAMA
and then talk to their doctor before deciding.
"The theory behind the vaccine is sound: If HPV infection can be prevented, cancer will not occur. But in practice, the issue is more complex. First, there are more than 100 different types of HPV and at least 15 of them are oncogenic. The current vaccines target only 2 oncongenic strains: HPV-16 and HPV-18. Second, the relationship between infection at a young age and development of cancer 20 to 40 years later is not known. HPV is the most prevalent sexually transmitted infection, with an estimated 79% infection rate over a lifetime. The virus does not appear to be very harmful because almost all HPV infections are cleared by the immune system. In a few women, infection persists and some women may develop precancerous cervical lesions and eventually cervical cancer. It is currently impossible to predict in which women this will occur and why. Likewise, it is impossible to predict exactly what effect vaccination of young girls and women will have on the incidence of cervical cancer 20 to 40 years from now. The true effect of the vaccine can be determined only through clinical trials and long-term follow-up."