Vaccines Tied to Declining Rates of HPV-Related Cancer

HPV (human papillomavirus) is a very common virus, with nearly 80 million people — about one in four — currently infected in the United States. Most significantly, it is a cancer-causing virus.

Today, March 4, is International HPV Awareness Day. The observance comes in the wake of a new study that finds two strains of the sexually transmitted HPV are showing significant declines among American women, and rising vaccination rates are likely fueling the trend. The study involved thousands of U.S. women who tested positive for pre-cancerous conditions of the cervix.

Rates of infection with HPV 16 or 18 — the two strains most tied to cervical cancer — have markedly declined between 2008 and 2014, researchers found. During that same period of time, the use of HPV vaccines such as Gardasil and Cervarix became more widespread. Both vaccines target HPV 16 and 18, among other strains.

Overall, HPV cancers include cancer of the cervix, vulva, vagina, penis, or anus. HPV infection can also cause cancer in the back of the throat, including the base of the tongue and tonsils.

“We’re seeing now that head and neck cancers are related to the human papillomavirus (HPV) and it’s becoming more and more apparent that these cases are increasing in incidence,” said Geoffrey Young, M.D., chief of head and neck surgery at Miami Cancer Institute. “There is good evidence to suggest that the HPV vaccine will help prevent future cancers.”

The latest study reaffirms the effectiveness of the HPV vaccine, researchers said.

“This is clear evidence that the HPV vaccine is working to prevent cervical disease in young women in the United States,” said the study’s lead author, Nancy McClung, Ph.D., R.N., epidemic intelligence service officer at the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta. “In the coming years, we should see even greater impact as more women are vaccinated during early adolescence and before exposure to HPV.”

The CDC estimates about 14 million people become newly infected with HPV each year, mostly teens and young adults. “Almost all sexually active individuals will get HPV at some point in their lifetime, but most HPV infections go away on their own without any treatment,” McClung explained in a news release from the American Association for Cancer Research.

But about 12,000 women are diagnosed with — and about 4,000 women die from — cervical cancer caused by certain HPV viruses. The American Cancer Society (ACS) is bolstering a campaign to further educate primary care physicians and family doctors about the importance of informing parents that the HPV vaccine is about cancer prevention.

“What causes cervical cancer in almost all cases is a persistent infection with the human papillomavirus (HPV),” said Eric Douglas Schroeder, M.D., gynecologic oncologist with the Miami Cancer Institute, during a recent Facebook Live session. “Most everyone will clear that virus through their own immune system. But for some reason, some strains of HPV stick around for a longer period of time and eventually it can lead to cervical cancer.

The CDC’s most recent statistics show that 49.5 of girls and 37.5 percent of boys aged 13-17 are up-to-date on all recommended doses of the HPV vaccine.

U.S. regulators in October expanded the use of the HPV vaccine to include men and women between the ages of 27 and 45. This approval should protect more people from several types of cancer caused by the human papillomavirus, known as HPV, experts say.

The U.S. Food and Drug Administration (FDA) broadened the approval of the vaccine, called Gardasil 9, which was previously approved for people ages 9 through 26. The vaccine is typically recommended to be given in two doses, several months apart, for those who are 9 through 14, and in three doses for those 15 through 26. For those older than 26, the recommended regimen will be three doses.

“This is a great step forward,” said Dr. Young, referring to the FDA’s approval. “Many adults have been exposed to some types of HPV. However, most have not been exposed to all nine types covered by the vaccine, some of which can cause cancer. ”

About 70 percent of oropharyngeal cancers (cancers that form in the tissues of the throat) are caused by high-risk HPV infection, and the incidence of HPV-positive cancers has been increasing in the United States in recent decades. Each year, about 31,000 men and women in the U.S. are diagnosed with a cancer caused by an HPV infection.