An editorial published two weeks ago in the New England Journal of Medicine (NEJM) raises serious questions concerning the effectiveness of Gardasil, Merck's cervical cancer vaccine, and explicitly calls for a more cautious approach toward public policy decisions on Gardasil vaccination.
The NEJM editorial accompanied the publication of a study in the same issue that found that the effectiveness of the vaccine was greatest when it was administered to girls and young women who had not previously been exposed to any of the four major types of human papillomavirus (HPV) that are associated with cervical cancer. Among this highly selected population, Gardasil was 98 percent effective in preventing infection with these four strains of HPV. However, the vaccine's effectiveness fell dramatically - to only 17 percent - when it was administered to girls and women in the broader population who had previously been exposed to HPV, and who already had very early signs of cervical pre-malignant change (Sawaya 2007).
Not only is the vaccine far less effective in the general population than Merck's publicity blitz had initially suggested, it may also be far less safe than originally assumed. According to documents obtained last month from the Food and Drug Administration under the Freedom of Information Act, more than 1,600 adverse reactions to the vaccine have already been documented by the FDA's Vaccine Adverse Event Reporting System (VAERS), including three deaths which were related to blood clotting (thrombosis). Among 42 women who were vaccinated with Gardasil while pregnant, 18 experienced reportable adverse events ranging from miscarriage to fetal abnormalities.