The effectiveness of the recently approved vaccination for human papillomavirus has come under question in an editorial in the New England Journal of Medicine. The vaccine, called Gardasil and owned by Merck & Co., proved 98% effective at preventing precancerous lesions of the cervix from two variants of the HP virus, HPV 16 and 18. However, the efficacy of the vaccine dropped to 17% when all precancerous lesions were considered in the study funded by Merck. Experts have suggested caution regarding the immediate use or even the legislation of inoculation, as was attempted by the state of Texas. Too many questions are unanswered regarding overall effectiveness, time-length of protection and potential adverse side effects. Concern has been raised over the fact that replacement may occur. If the vaccine removes the damaging effects of HPV 16 and 18, other variants of the virus may fill in and continue to cause cancerous lesions (John Carreyrou and Keith Winstein, "Medical Journal Questions Efficacy of HPV Vaccine," The Wall Street Journal, May 10, 2007).