More girls in the United States are vaccinated with Gardasil, the vaccine designed to prevent cervical cancer and genital warts, according to a report released last week by the Centers for Disease Control and Prevention.

Gardasil, produced by Merck, got the Food and Drug Administration approval back in 2006. The vaccine is given to teenage girls and young women as protection against four strains of the human papillomavirus, two of which accounting for about 70 percent of cervical cancer cases. Last month, Gardasil received FDA approval for vulvar and vaginal cancers as well. These cancers affect more than 5,000 women annually in the United States.

The CDC currently recommends Gardasil for 11 and 12-year-old girls, because nearly none of them has begun their sex lives, and therefore they haven’t been exposed to the virus. For that reason, Gardasil will offer them maximum protection.

According to the report, 25.1 percent of the teen girls involved in the CDC survey had received at least one dose of Gardasil. The vaccine is given in a three-dose series. The survey involved about 3,000 teen girls ages 13 to 17.

The percentage is encouraging and the CDC hopes it will rise to 90 percent, thus reducing significantly the number of cervical cancer in the US. There were an estimated 11,000 new cases of cervical cancer and 3,600 deaths in the US last year.

“There's a lot of good news in the survey results,” said Dr. Lance Rodewald, director of the CDC's Division of Immunization Services.

The percentage is also good news for Merck considering the fact that back in July Gardasil was linked to 7,802 reports of adverse events in people who received it.

The Vaccine Adverse Events Reporting System (VAERS), a system of monitoring vaccines’ side effects belonging to the CDC and the Food and Drug Administration, registered the reports between June 8, 2006 and April 30, 2008.

The reports included 15 deaths and 31 cases of Guillain-Barre syndrome, a life-threatening condition in which the body’s immune system attacks part of the nervous system, eventually leading to paralysis. Other side effects related to the vaccine were nausea, itchy red rash and difficulty breathing.

Merck defended the vaccine at the time saying that a report of an adverse reaction “does not mean that a causal relationship between and event and vaccination has been established – just that the event occurred after vaccination.” However, the company is working with the FDA and the CDC to establish if there was a direct link between the signaled adverse effects and the vaccine.

Currently Gardasil is the only cervical cancer vaccine on the market. It has racked up about $1,5 billion in sales since its June 2006 U.S. launch. Cervarix, a similar vaccine made by rival GlaxoSmithKline, is expected to hit the market by the middle of 2009.