Q & A Library

The vaccine you're wondering about protects against infection with two strains of the human papillomavirus (HPV), which are responsible for 70 percent of all cases of cervical cancer. The FDA approved the vaccine (Gardasil) in June 2006, and that same month, a federal advisory panel on immunization practices recommended that all 11 and 12 year old girls be vaccinated. More than half of all men and women pick up HPV within a year of becoming sexually active. The vaccine won't work for women who already are infected with HPV, which is why it is important to immunize young girls before they become sexually active.

There are more than 100 strains of HPV, and more than 30 of them are sexually transmitted. Of those, HPV strains 16 and 18 are linked to most cases of cervical cancer. In 90 percent of all cases, HPV infections clear up on their own and cause no obvious symptoms (except, in some cases, genital warts; the new vaccine will also protect women against the viruses responsible for 90 percent of all cases of warts). HPV infections that linger can initiate cervical changes that can lead to cancer. The changes can be picked up on Pap smears, but still, some 10,000 women in the United States develop cervical cancer every year, and the disease leads to about 3,900 deaths annually. Most of those cases and deaths could be prevented if all women had Pap smears. Worldwide, cervical cancer kills more than 288,000 women per year. Women who are vaccinated will still need Pap smears to check for cervical changes due to other HPV strains.

The vaccine is given in three shots administered over a period of six months; it will cost $360 (the cost probably will be covered by health insurance). According to the FDA, side effects are mild - the worst appear to be some temporary tenderness or pain at the injection site. At present, the vaccine is approved for use only among girls and women from age nine through 26. Eventually, it may be recommended for teenage boys, men and older women; tests for efficacy in these groups are underway.

This is a big public health step forward. The vaccine undoubtedly will save thousands of lives around the world among your daughter's generation and future generations of women.

Andrew Weil, M.D.