Infection rates of the human papilloma virus (HPV) — a sexually transmitted disease with a proven link to cancer — have plummeted since a vaccine to prevent the disease was introduced in 2006, a new study says.
HPV is a primary cause of cervical cancer in young women, and an oral HPV infection can lead to oral cancer. There are more than 40 subtypes of HPV that can infect the genital area and the throat.
The HPV vaccine is an important public health intervention for girls and women ages 9 to 26. Vaccination is most effective in childhood or early adolescence, before sexual activity begins and possible exposure to the virus. Older adolescents also may also benefit from the vaccine.
The CDC recommends girls and boys get the HPV vaccine beginning at age 11. The vaccine is recommended for women until age 26 and men until age 21.
Researchers at the U.S. Centers for Disease Control and Prevention (CDC) looked at HPV rates from the years 2003 to 2006 — the years before women started receiving the vaccine — and compared them with infection rates over the next six years, from 2006 to 2012.
They found a substantial drop in HPV infection among girls ages 14 to 19 and a smaller, but significant drop in women ages 20 to 24.
They also tested eight HPV strains that are not covered by the vaccine and found no significant difference in rates during the same time frame, which indicates the effectiveness of the HPV vaccine.
It’s no surprise that the drop in HPV infections in the last decade is because of the higher incidence of vaccination, says women’s health physician Salena Zanotti, MD.
“We’re very good at managing pre-cervical cancer in our country, which is why we don’t see cervical cancer as often,” Dr. Zanotti says. “Hopefully we will see very few of these patients in the future because of the vaccine.”
More vaccination, fewer infections
Newer versions of the vaccine are more powerful than the original, Dr. Zanotti says. The original vaccine protected against two low-risk and two high-risk strains of HPV. The newer versions protect against nine cancer-causing strains: two of which are low-risk, seven of which are high-risk.
“Ideally I think we’re going to get up to 90 percent coverage of the cancer-causing strains, as opposed to the percentage we were getting with the first one, so that’s exciting,” Dr. Zanotti says.
Three vaccines now are available to prevent the HPV types that cause most cervical cancers as well as some cancers of the anus, vulva (area around the opening of the vagina), vagina and the back of throat, including the base of tongue and tonsils. Two of these vaccines also prevent the types of HPV that cause most genital warts.
The vaccines are given in three shots over a six-month period.
Although rates of HPV vaccination have been increasing in the United States, the number of people who have received the vaccine is still low, the study says. In 2013, a national survey found that 57 percent of 13- to 17-year-old females had received at least one dose and just 38 percent had received all three doses, the study says.
Complete results for the study appear online in the journal Pediatrics.
Cervical cancer guide