The first vaccine to protect against most cervical cancer won U.S. federal approval Thursday.
The vaccine Gardasil, approved for use in girls and women ages nine to 26, prevents infection by four strains of the human papillomavirus, or HPV, Merck & Co. Inc. said. The virus is the most prevalent sexually transmitted disease.
Gardasil protects against the two types of HPV responsible for about 70 per cent of cervical cancer cases. The vaccine also blocks infection by two other strains responsible for 90 per cent of genital wart cases.
Merck is expected to market Gardasil as a cancer vaccine, rather than an STD vaccine. It remains unclear how widespread will be the use of the three-shot series, in part because of its estimated cost of $300 to $500 US. Conservative opposition to making the vaccine mandatory for school attendance may also curb its adoption.
The target age for receiving Gardasil is low because the vaccine works best when given to girls before they begin having sex and run the risk of HPV infection. The vaccine may not protect people already infected and may increase their risk of the kind of lesions that can lead to cervical cancer, the FDA has said.
The national Advisory Committee on Immunization Practices will decide June 29 whether to endorse routine vaccination with Gardasil. That endorsement is critical if a vaccine is to become a standard of care.
It then will be up to individual U.S. states to decide whether to add the vaccine to the list of others required before students may attend public schools.
Conservative groups like Focus on the Family support availability of the vaccine, but oppose making it mandatory, saying the decision to vaccinate should rest with a child's parents or guardians. It promotes abstinence as the best way of warding off infection by HPV and other STDs.
HPV affects more than 50 per cent of sexually active adults at some point in their lives. The cervical cancer it can cause kills about 290,000 women worldwide each year. Regular Pap smears often detect precancerous lesions and early cancer. The vaccine does not eliminate the need for regular screening.
Analysts believe Gardasil sales could top $1 billion a year for Merck, which is battling thousands of lawsuits over its withdrawn painkiller Vioxx. The New Jersey company is seeking to license Gardasil in more than 50 countries.
GlaxoSmithKline PLC is also developing an HPV vaccine.