HPV Vaccine Substantially Reduces Cervical Cancer Rates

Human papillomavirus is actually a group of more than 200 viruses.

"HPV is the most prevalent of all sexually transmitted infections (STIs) and nearly all sexually active individuals will acquire an infection with one or more strains of this virus," said Felice Gersh, M.D., OB-GYN, founder of the California-based Integrative Medical Group of Irvine, who added that you can get an HPV infection in the throat, genitals, vagina and cervix.

Most of the time, your immune system will control and completely get rid of the HPV infection. However, an HPV infection can become chronic and lead to other health conditions, such as genital warts, pre-cancerous cells and certain cancers including cervical cancer.

Almost all cases of cervical cancer are caused by an HPV infection. Cervical cancer, Gersh explained, is one of the first cancers shown to be caused by a virus.

When we think of cancer, we tend to think of environmental factors, such as toxins, and genetic components, such as a parent or sibling having cancer. However, certain viruses, including HPV, have shown us cancer can also come from infections. Since we know that, Gersh stressed, eliminating that infection with a vaccine has the power to prevent deadly cancers.

Cervical cancer is the fourth most common cancer worldwide, according to the World Health Organization. Thanks to improved screening and the HPV vaccine, it's on the decline in many countries, including the U.S.

Ruanne Barnabas, a professor of global health at the University of Washington School of Medicine, is the co-principal investigator of a randomized controlled trial in Kenya that showed the effectiveness of a single-dose HPV vaccine. Cervical cancer in Kenya is six times more widespread than it is in North America and Europe.

"In countries such as Australia and the United Kingdom where they have universal access and a national medical system, vaccination rates are very high," Barnabas said. These countries are on the path to eliminating cervical cancer.

"Rwanda has outstanding coverage of HPV vaccination," Barnabas continued, adding that the U.S. is getting there: about 60 percent of people have completed the vaccines, and 75 percent of teenagers have received at least one dose.

Barnabas's research for the KENya Single-dose HPV-vaccine Efficacy (KEN SHE) study is finding that one dose of the HPV vaccine provides complete coverage against HPV infection versus the current multiple-dose regimen.

The HPV vaccine is designed to prevent our bodies from getting an infection from HPV, Gersh said. It's not designed to treat or eradicate an infection we already have. Therefore, the HPV vaccine is best given prior to the onset of sexual activity, for both males and females. That's why, Gersh explained, it's recommended to be given to prepubescent adolescents.

The younger the better, in this case. The age range to be vaccinated to realize the most benefit is 12 to 13 years old. But getting vaccinated older than that still provides needed protection. It's a totally worthwhile public health goal, Barnabas said, because cervical cancer is so much more difficult to diagnose and treat.

"It's true that if you're vaccinated before you're exposed to HPV, the vaccine has the highest chance of being successful and protecting you completely from all HPV types," Barnabas explained. "The vaccines we have cover and protect us against 90 percent of cancers. But even after people have been exposed to HPV, as long as they don't have HPV at the time of vaccination, the vaccines are still highly effective."

So getting vaccinated all the way up to age 45 still prevents cases of cervical cancer when you look at it from a public health perspective. Cervical cancer, Barnabas warned, is often diagnosed late, and many people die from it. "Even if it's not perfect protection, as you have with vaccinating 12- to 13-year-olds, you can still prevent a lot of HPV infections."

It's a game-changer, Barnabas said. "In Kenya, everyone is really excited about [the KEN-SHE] results, because it's been so challenging, logistically, to deliver two doses."

Currently, in the U.S., two doses of the HPV vaccine are given six to 12 months apart for full protection in people younger than age 15. For recipients older than 15, three doses spread out over six months are recommended.

"The fact that efficacy is near perfect for HPV vaccines is incredible," Barnabas said. "The virus is very stable. For hundreds of years, there have been no mutations, no changes or variants. It's the best-case scenario."

Consider talking with your healthcare provider about the HPV vaccine and its benefits if you haven't already received it.