A Scottish Study on HPV Vaccine Shows Remarkable Reduction in Cervical Cancer Incidence
A groundbreaking Scottish study has revealed an astounding reduction in the incidence of cervical cancer among women who received the human papillomavirus (HPV) vaccine. The observational study tracked the effectiveness of the vaccine and found that no cases of cervical cancer were reported in women who were immunized at the ages of 12 or 13. Furthermore, there was a significant decrease in the occurrence of cervical cancer among vaccinated women between the ages of 14 and 22 when compared to those who were not vaccinated.
The study, which utilized screening, vaccination, and cancer registry data from across Scotland, analyzed information for women born between January 1988 and June 1996. Throughout the study, different types of vaccines were administered as newer versions became available. The earlier generation of the vaccine was the bivalent Cervarix, followed by the quadrivalent Gardasil until the recent introduction of the 9-valent Gardasil.
Scotland implemented routine immunization in schools in 2008, and the impact of this campaign has been remarkable. By the time students entered their fourth year of secondary school (equivalent to 10th grade in the U.S.) in the 2022-2023 academic year, nearly 90% had received at least one dose of the HPV vaccine. In stark contrast, the United States, where HPV vaccines are not administered in schools, has a much lower uptake rate among adolescents, with only around 60% receiving the vaccine.
HPV is responsible for several types of cancer, including cervical cancer, as well as causing genital warts. It is the most common sexually transmitted disease among women. In the U.S. alone, approximately 14,000 new cases of invasive cervical cancer are diagnosed annually, leading to nearly 4,400 deaths.
On a global scale, cervical cancer poses a significant burden. According to data from the World Health Organization, it is the fourth most common cancer in women worldwide, with an estimated 604,000 new cases and 342,000 deaths recorded in 2020. The majority of cervical cancer cases and fatalities occur in low- and middle-income countries due to limited access to HPV vaccines, cervical screening, and treatment services.
The HPV vaccine is highly effective in preventing more than 90% of HPV-related cancers. Implementing prophylactic vaccination combined with the evaluation and treatment of precancerous lesions has proven to be an effective strategy for preventing cervical cancer. The vaccine is administered in two or three doses, depending on the age at which the individual receives their initial vaccination.
The U.S. Centers for Disease Control and Prevention recommend routine vaccination for individuals between the ages of 11 and 12, with immunization available for everyone up to the age of 26 who have not received adequate vaccination earlier. However, vaccination is generally not recommended for individuals older than 26, mainly because many in this age group have already been exposed to HPV.
While rates of cervical cancer have decreased by more than 50% in the U.S. since the 1960s, it is concerning that incidence rates have been rising among women in their 30s and early 40s. Between 2012 and 2019, the diagnosis of cervical cancer in women aged 30 to 44 increased by almost 2% annually.
One of the most worrisome factors is that over 50% of women diagnosed with cervical cancer in the U.S. have either never undergone screening or have not been evaluated in the past five years, according to the CDC. Regular screening allows doctors to identify the presence of HPV and detect, remove, and analyze potentially precancerous lesions.
The National Cancer Institute estimates that the percentage of women ages 21 to 65 who have been screened for cervical cancer has fallen from 87% in 2000 to 72% in 2021, highlighting the need for increased screening efforts. The U.S. Preventive Services Task Force recommends Pap smears every three years for women aged 21 to 29, while women aged 30 to 65 can opt for either a Pap smear every three years or a cervical screening test every five years, which detects HPV. Some women may choose a combination of a Pap smear and an HPV test.
Following abnormal screening results, it is essential for individuals to receive follow-up care. However, a study published in the American Journal of Preventive Medicine found that only 73% of women did so, indicating a need for improved access to healthcare.
In Scotland, the National Health Service invites women between the ages of 25 and 64 for routine screening every five years. If HPV is detected during previous testing, the frequency of screening is increased, and cells from the cervix are examined for abnormality, though it is no longer routine to examine these samples under a microscope for abnormal cells.
A key distinction between Scotland and the U.S. lies in the incorporation of routine HPV immunization in Scottish schools, which has clearly had a positive impact on public health. The success of Scotland’s approach calls for a reevaluation of strategies in countries that do not administer the HPV vaccine through school-based programs.
The results of the Scottish study highlight the significant potential of HPV vaccination in decreasing the incidence of cervical cancer. By prioritizing immunization and regular screening, countries can save lives and reduce the burden of this devastating disease on women worldwide.
