The U.S. Centers for Disease Control and Prevention released the first government report on Gardasil vaccinations, which showed 2.5 million girls ages 13 to 17 had gotten the first of three doses.

Merck´s Gardasil was approved by the U.S. Food and Drug Administration (FDA) in June 2006, and is the first vaccine to protect against cancer-causing strains of the human papillomavirus (HPV) in women and girls ages 9 to 26.

Merck spent $100 million dollars on television and print advertisements for Gardasil in 2007, according to Nielsen Monitor-Plus, helping make it Merck´s second-fastest growing product that year. In the first six months of 2008, Merck had worldwide earnings of $ 716 million dollars from Gardasil, of which $ 548 million dollars were in the U.S. alone.

Merck is now shooting for women older than 18, who are less likely to have gotten the vaccine. A Merrill Lynch research report projected that about 15 percent of women ages 19 to 26 have been vaccinated with Gardasil.

In March 2007, the CDC recommended that girls ages 11 to 12 should routinely get the shot and that older girls and young women should be given catch-up vaccinations.

“For a new vaccine, 25 percent is really very good,'' said Lance Rodewald, director of the division of immunization services at the CDC. “We need to see that rate every year if we are going to meet our goal of 90 percent.''

The report from Atlanta-based CDC randomly sampled almost 3,000 girls ages 13 to 17. The survey also found an increase since 2006 in vaccines for tetanus, diphtheria, hepatitis B, measles, mumps and rubella.

Gardasil was designed as a protection against four strains of the sexually transmitted virus that cause 70 percent of cervical cancers and 90 percent of genital warts. More than $ 2 billion dollars is spent on the treatment of cervical cancer each year in the U.S., according to the agency.

U.K.-based GlaxoSmithKline Plc has developed a similar vaccine called Cervarix, and is currently seeking U.S. regulators´ approval.