A recent study from the Karolinska Institutet has found that girls vaccinated against human papillomavirus (HPV) are less likely to develop severe precancerous lesions of the vulva and vagina. The findings, published in JAMA Oncology, indicate that vaccination before the age of 17 provides even greater protection.
In Sweden, children in middle school receive HPV vaccinations as part of a national program aimed at preventing cervical cancer and other diseases caused by HPV. The quadrivalent vaccine used in this program targets HPV types 6, 11, 16, and 18.
Researchers analyzed data from over 770,000 women born between 1985 and 1998 who lived in Sweden between 2006 and 2022. By using Swedish health registries, they tracked the development of high-grade lesions among those who had received at least one dose of the vaccine compared to those who were unvaccinated. After accounting for variables such as age, education level, income, and maternal medical history, results showed that vaccinated women had a 37 percent lower risk of developing these severe lesions than unvaccinated women. Those vaccinated before turning 17 experienced a reduction in risk by 55 percent.
The research team plans further studies to evaluate how different types of HPV vaccines perform over time and their impact on other cancers linked to HPV infection.
"We also want to study the vaccines' effect on other HPV-related cancers, including in men." says Jiayao Lei, assistant professor at the Department of Medical Epidemiology and Biostatistics and the Center for Cervical Cancer Elimination at the Department of Clinical Science, Intervention and Technology, Karolinska Institutet, who led the study.
The project was conducted with support from the Public Health Agency of Sweden and Karolinska University Hospital. Funding was provided by several organizations including the Swedish Research Council, Swedish Cancer Society, Forte, Karolinska Institutet's strategic research area in epidemiology and biostatistics, as well as Horizon 2020 from the European Union.
