Scotland Study Shows HPV Vaccine Eliminates Cervical Cancer in Vaccinated Women
A groundbreaking study conducted in Scotland has revealed the remarkable real-world impact of the human papillomavirus (HPV) vaccine in preventing cervical cancer. The study, which monitored a national cohort of women born between 1988 and 1996, found that there were no cases of cervical cancer among those who were fully vaccinated against HPV between the ages of 12 and 13.
Previous studies have already established the high efficacy of HPV vaccines in preventing cervical cancer. However, this study, published in the Journal of the National Cancer Institute, is the first to observe a national cohort of women over an extended period and discover no instances of cervical cancer.
Kathleen Schmeler, a professor of gynecologic oncology at the University of Texas MD Anderson Cancer Center, expressed her excitement about the study’s findings, stating, “The study is super exciting. It shows that the vaccine is extremely effective.” She also acknowledged that it takes time to see the full impact of the vaccine, as there is a delay between vaccination and its effects.
The results of this study emphasize the importance of increasing HPV vaccine uptake in the United States. Scotland introduced routine immunization in schools in 2008, resulting in nearly 90% of fourth-year secondary school students receiving at least one dose of the vaccine in the 2022-2023 school year. In contrast, HPV vaccines are not administered in schools in the U.S., leading to a lower uptake among adolescents aged 13 to 17, at just over 60%.
The study also highlights the significance of timely vaccination. Schmeler noted that the women who did not develop cervical cancer were vaccinated before becoming sexually active. She emphasized the need to adhere to vaccination guidelines and administer the vaccine prior to sexual activity.
One notable finding from the Scotland study is that receiving the HPV vaccine before the age of 14 provides significant benefits. Among the women vaccinated before turning 14, no cases of cervical cancer were found, even if they had only received one or two doses of the vaccine instead of the recommended three-dose protocol. Additionally, women who received the three-dose protocol between the ages of 14 and 22 also experienced a considerable reduction in cervical cancer incidence compared to unvaccinated women.
Tim Palmer, the former clinical lead for cervical screening in Scotland and an HPV immunization consultant at Public Health Scotland, expressed his surprise at the absence of cancer cases in the group vaccinated before the age of 14. He expected around 15 to 17 cases per year in Scotland for that age group but found none.
The types of HPV vaccines administered to the monitored cohorts changed over time as newer vaccines became available. Initially, the bivalent Cervarix vaccine, targeting HPV 16 and 18, was used until 2012. It was then replaced by the quadrivalent Gardasil vaccine until 2023 when the nonavalent Gardasil 9 was introduced.
It is important to note that cervical cancers may still occur in vaccinated women due to HPV strains not targeted by earlier vaccines. Palmer explained that there are other HPV types that can cause cancer, and while the current results indicate no cases of cervical cancer caused by high-risk strains of HPV, cases caused by less high-risk strains may emerge in the future.
Palmer emphasized that the study’s findings do not diminish the need for continued screenings to detect cervical cancers caused by HPV types not targeted by the original bivalent vaccine. However, the vaccines have proven effective against the more aggressive strains of HPV (16 and 18).
The impact of vaccination was particularly significant among women of lower socioeconomic status, who typically report higher occurrences of cancer. This finding underscores the importance of ensuring equitable access to vaccines for all populations.
Ville Pimenoff, a senior researcher at the Karolinska Institutet and professor at the University of Oulu in Finland, published a similar study in November 2023, demonstrating the effectiveness of cohort vaccination in creating herd immunity against HPV. Pimenoff believes that the results from Scotland confirm his findings, stating, “When you vaccinate in a cohort way, there seems to be very strong, protective immunity in those communities.”
The Scotland study provides compelling evidence of the effectiveness of HPV vaccines in eliminating cervical cancer among vaccinated women. It highlights the importance of timely vaccination and the need to increase vaccine uptake worldwide. While further research is necessary to address the potential impact of other HPV strains, these findings offer hope for a future where cervical cancer can be eradicated through widespread vaccination efforts.
