HERSHEY, Pa. — Women who are vaccinated against human papillomavirus (HPV) are more likely to undergo cervical cancer screenings than unvaccinated women, according to new research by Penn State College of Medicine. HPV is the most common sexually transmitted infection in the United States, according to the Centers for Disease Control and Prevention. More than 140 strains of HPV exist, and oftentimes infections will clear up without medical treatment. However, certain high-risk strains can lead to serious health problems, such as genital warts and cervical cancer.
While there is no cure for HPV, routine cancer screenings and HPV vaccinations have been shown to reduce rates of cervical cancer. Multi-dose HPV vaccines — such as Gardasil and Cervarix — were introduced in the early 2000s for male and female patients, 9 to 26 years old. Data from the CDC show that these vaccines can prevent more than 90% of HPV-related cancers, as well guard against precancerous cells.
“Our findings highlight the importance of continued routine screening for cervical cancer, regardless of a person’s HPV vaccination status,” said lead investigator Djibril Ba, research data management specialist in the Department of Public Health Sciences. “More studies are needed to better understand cervical cancer screening behaviors in the vaccine era.”
Dosage schedules for the HPV vaccine vary by age for patients. Patients ages 9 to 26 may need to get two or three doses of an HPV vaccine to be fully vaccinated.
The investigators reviewed data from nearly 1 million privately insured U.S. women — ages 21 to 26 — to examine factors associated with cervical cancer screenings from 2006 through 2016. The team assessed an array of factors, such as a patient’s HPV vaccination status, medical history, mental health, lifestyle choices and geographical location, to see how these affected cervical cancer screenings.
The findings reveal that cancer screening behaviors differed between vaccinated and unvaccinated women. The investigators found that among the study population, about 20% of the individuals were vaccinated against HPV. Of those who were vaccinated, 44.9% received a single dose of the HPV vaccine, while 28.3% received two doses and 26.8% received three doses.
According to the study, women who received at least one dose of the HPV vaccine were 34% more likely to undergo cervical cancer screenings than those who were unvaccinated. The researchers found that the rate of cancer screenings increased as the dose of HPV vaccination increased, and that fully vaccinated individuals were the most likely to undergo screenings. The study also revealed that cancer screening rates were down, overall, during this 10-year period. Overall, findings reveal that 49.8% of women underwent cervical cancer screenings.
In addition, the researchers found that vaccinated individuals had higher levels of health care utilization before receiving the HPV vaccine compared to their unvaccinated counterparts. Based on these findings, the investigators said that increased access to care and information about preventive services might translate into more patients getting the HPV vaccine and/or undergoing cancer screenings.
The research team also witnessed geographical differences. The vast majority of patients lived in urban areas. Findings revealed that women living in the South had the highest cervical cancer screening rates, while those living in western states had the lowest screening rates.
Insurance coverage may also influence whether or not women receive preventive services. According to the study, those with high-deductible insurance plans had lower cervical cancer screening rates than women with other medical coverage.
“Our results strongly suggest that access to and uptake of different types of preventive health services, in this case, vaccination and cancer screening, go hand-in-hand,” said researcher Dr. Jennifer McCall-Hosenfeld, associate professor, departments of Medicine and Public Health Sciences. “Addressing barriers to the receipt of preventive health services — whether the barriers are informational, financial, cultural or logistical — is critical to reducing the burden of preventable disease. Vaccines are central to the mission of public health.”
The researchers said that completing the HPV vaccination schedule might have helped patients adhere to routine cervical cancer screenings. Based on these findings, health care providers should educate patients about the HPV vaccine’s effectiveness at preventing cancer and stress the importance of routine screenings, such as pap tests. Screenings may aid in detecting and treating related health issues.
The researchers noted some limitations that could be addressed in future studies. The study population was limited to patients with commercial, private health insurance and may not be generalizable to non-privately insured populations. The researchers were only able to capture HPV vaccination status of individuals who received their vaccines after enrolling in the MarketScan database.
Penn State researchers Paddy Ssentongo, Vernon Chinchilli, Edeanya Agbese, Guodong Liu and Douglas Leslie contributed to this research. Ping Du from Takeda Pharmaceutical Company also contributed this study.
The researchers declare no conflicts of interest or specific funding support.
Read the full study in Medicine.