A new study has found a dramatic drop in the rates of cervical pre-cancers among young adult women. This is great news and further proof that the HPV vaccine is working.

HPV is a group of over 100 different types of viruses. Some types of HPV can cause genital warts and other types—referred to as high risk types—can cause cancer of the cervix, vulva, vagina, penis or anus, as well as cancer in the back of the throat. The HPV vaccine protects against nine types of HPV associated with genital warts and cancer.

We already know that the vaccine is working. Infections with the types of HPV that are most likely to cause cancers and genital warts have dropped by 88 percent in teen girls and 81 percent in young women. We also know that cervical cancer rates have been dropping since the introduction of the vaccine. Rates for women ages 20 to 24 declined 11% each year between 2012 and 2019. This is the age group most likely to have gotten the vaccine before they were sexually active.

Preventing Cervical Pre-Cancers

The new study looks at cervical pre-cancers. Cervical cancer develops gradually as cells experience abnormal changes. These changes can be detected through a Pap test—also referred to as cytology—where samples of cells from the cervix are collected and examined under a microscope. These tests can detect abnormal cell changes, sometimes called cervical dysplasia, long before they become cancer, and treatments can’t prevent cancer from ever forming. This is why screening is so important.

Pre-cancers are classified by severity or likelihood of become cancer:

• Mild cases are classified as CIN1. Most people with CIN1 do not require treatment because the body can often clear these mild changes on its own.
• More severe cellular changes are classified as CIN2 and CIN3. These are more likely to become cervical cancer if not treated.
  • Some people with CIN2 are treated while others are monitored closely to see if the abnormal changes persist.
  • Most people with CIN3 receive treatment to prevent the changes from becoming cervical cancer.

The new study found that rates of CIN2 and CIN3 have fallen dramatically especially among the youngest women. Between 2008 and 2022, rates of CIN2 pre-cancers fell 79% among young women who were 20 to 24 at the end of the study period. During that same time rates of CIN3 pre-cancers among this group fell 80%. Rates also dropped among older women. Those who were 25-29 in 2022 saw a 37% drop in CIN3 pre-cancers. The HPV vaccine was approved in 2006, meaning it would have been available when most of these women turned 11 or soon after.

In contrast, pre-cancer rates rose among women who were 40-49 and 50-64 in 2022. These women would have been between 24 and 48 when the vaccine was first introduced, and thus many of them missed the window for vaccination. If they were vaccinated, it was likely after they’d become sexually active.

The study was published in the CDC’s Morbidity and Mortality Weekly Report. The authors conclude, “These data are consistent with considerable impact of HPV vaccination for preventing cervical precancers among women in the age groups most likely to have been vaccinated and support existing recommendations to vaccinate children at the routinely recommended ages as a cancer prevention measure.”

At a time when anti-vaccine sentiment is high, results like these can remind us why vaccinations are so important. This study adds to information we already had showing that the HPV vaccine is successfully preventing cancer.