The HPV vaccine: Is it working yet?

We’ve called HPV (human papillomavirus) the common cold of the sexually active world—but just because it’s common doesn’t mean it’s not worth preventing when possible. While there are 40 different strains of the virus, only a couple of them are the major cause of cervical cancer (types 16 and 18) and most genital warts (types 6 and 11). In 2006, young women in the U.S. started using a vaccine—Gardasil—that protects against those four types of HPV. We know from studies that the vaccine works well for a single woman, but it’s still too soon to tell whether we’ll be able to see a large-scale effect in the U.S. overall. Cervical cancer usually develops many years after a woman first contracts HPV, and it’s only been six years since the vaccine became available. It will be another decade or more before we can say whether using the vaccine reduces the number of women with cervical cancer.

Genital warts, on the other hand, usually develop within a few weeks or months after exposure to one of the HPV strains that causes them. So it’s pretty exciting that a new study from the California Department of Public Health suggests that there may be a decrease in genital warts among young Californians. The researchers looked at visits to California Family PACT docs, who serve about 2 million clients a year. They compared the number of genital warts cases from 2007 to 2010 and found significant decreases among women and men under age 26, while the number of cases for clients age 26 and over stayed the same or increased. The researchers can’t say for sure that these changes were related to the HPV vaccine, but it’s a promising sign.

In less awesome news, another recent study showed that fewer than half of people who start the HPV vaccine get all three injections in the recommended time frame of less than 1 year. To get the best protection from HPV, you’ve got to get all three shots. On the one hand, it can be a pain to go to the doctor three times in a year—on the other, it’s fewer trips than somebody with genital warts or cervical cancer would probably make. And you know what Ben Franklin would say: ounce of prevention, pound of cure.