A major long-term study led by researchers at Albert Einstein College of Medicine has confirmed that the human papillomavirus (HPV) vaccine works extremely well—not just for those who get the shot, but also for those who don’t.
The study found that the vaccine greatly reduces HPV infections, which are the main cause of cervical cancer and several other types of cancer. The results were published in the journal JAMA Pediatrics.
HPV is the world’s most common sexually transmitted infection and causes over 690,000 new cancer cases every year. These include cancers of the cervix, head, neck, and other genital areas in both men and women.
While past clinical trials showed that HPV vaccines are effective, this new study focused on how well the vaccine works in the real world.
Lead researcher Dr. Jessica Kahn explained that people in earlier studies were usually healthier and had a lower risk of HPV. The goal here was to see how well the vaccine works for young women in real-life situations—including those at higher risk.
The researchers studied 2,335 young women in Cincinnati over 17 years, starting in 2006, just before the first HPV vaccine was introduced. The participants were ages 13 to 26 and many had sexual histories that put them at higher risk for HPV. About 79% had more than one male partner, and over half had already had a sexually transmitted infection.
The researchers tracked infection rates as HPV vaccination became more common. Over time, vaccination rates in the group rose from 0% to 82%. As more participants got vaccinated, infections from the HPV types covered by the vaccines dropped sharply.
Among vaccinated women: Infections from types in the 2-valent vaccine fell by 98.4%. Infections from types in the 4-valent vaccine dropped by 94.2%. Infections from types in the 9-valent vaccine decreased by 75.7%.
These are significant drops and prove that the vaccine works well outside of clinical trials. The researchers also looked at whether the decrease in infections was due to changing behaviors, like fewer sexual partners, but found that the vaccine itself was the main reason for the improvement.
Even more encouraging was the discovery of strong herd immunity. Among unvaccinated women: Infections from types in the 2-valent vaccine dropped by 71.6%. Infections from types in the 4-valent vaccine fell by 75.8%.
This means that as more people got vaccinated, the virus spread less—even to people who hadn’t gotten the shot. This protective effect was especially strong because both boys and girls were vaccinated.
While the study didn’t have enough data yet to show herd immunity from the newest 9-valent vaccine, the early signs are promising.
Dr. Kahn emphasized the global importance of these findings. In the U.S., cervical cancer rates are already going down because of widespread vaccination.
But in many countries, especially in low-resource areas, cervical cancer is still the leading cause of cancer death in women. Only 27% of girls worldwide have received at least one dose of the HPV vaccine. In some regions, the rate is as low as 1%.
This study shows that expanding access to the HPV vaccine could save countless lives. It not only protects individuals but also helps entire communities by slowing the spread of the virus. Combined with screening and treatment programs, vaccination could lead to the elimination of cervical cancer around the world—a major public health victory.
The study is published in JAMA Pediatrics.
Copyright © 2025 Knowridge Science Report. All rights reserved.
