The Food and Drug Administration (FDA) approved Gardasil, Merck's new vaccine that protects against human papillomavirus (HPV) and cervical cancer. This is one of the greatest public health victories since the polio vaccination. FDA experts declared the vaccine safe and effective for girls and women ages nine to 26, and a similar vaccine produced by GlaxoSmithKline has been shown to be effective for women up to 55 years old.

Both Merck's HPV vaccine and the GlaxoSmithKline vaccine have proven 100% effective against the two strains of HPV that account for 70 percent of the incidents of cervical cancer in the United States. Recent studies suggest that the Merck vaccine is also effective against strains that cause vaginal and vulvar cancers and is 99 percent effective against the two strains of HPV responsible for 90 percent of genital warts.

HPV is a little known but very common sexually transmitted infection that is the primary cause of cervical cancer in the U.S. The Centers for Disease Control (CDC) estimates that some 20 million Americans have been exposed to HPV, although the vast majority of these infections are with strains that cause no significant health consequences. Two strains, however, are responsible for most cases of cervical cancer in the U.S., a disease that each year affects over 10,000 women in the U.S. and kills more than 3,700 of them.