Two major Cochrane reviews provide strong, consistent evidence that HPV vaccines are highly effective in preventing cervical cancer and pre-cancerous changes, especially when given before age 16. Girls vaccinated before 16 were found to be 80% less likely to develop cervical cancer. The vaccines are also confirmed to be safe, with only minor, temporary side effects such as a sore arm.
The first review, based on 60 randomized trials involving over 157,000 participants, showed that HPV vaccines (including Cervarix, Gardasil, and Gardasil-9) effectively prevent HPV infections and pre-cancerous lesions, with no evidence of serious safety concerns. Serious side effects occurred at similar rates in vaccinated and unvaccinated groups.
The second review, covering 225 observational studies and more than 132 million people, confirmed that HPV vaccination reduces cervical cancer, high-grade pre-cancer (CIN2+ and CIN3+), and anogenital warts in real-world settings. Protection is strongest when vaccination happens at or before age 16. No link was found between HPV vaccination and serious adverse events.
Together, the reviews provide the most comprehensive evidence to date that HPV vaccination is a safe and effective global public health measure capable of preventing many cancers. They reinforce recommendations to vaccinate both boys and girls before exposure to HPV. More research is needed in low- and middle-income countries, where the burden of cervical cancer is greatest, and long-term follow-up will help clarify the impact on other HPV-related cancers that develop later in life.
Credit: University of Exeter