HPV vaccination in the United States
The HPV vaccination program is similarly reducing the incidence of and mortality from cervical cancer among younger women in the United States who are most likely to have received the vaccine. As reported by lead author, Justin Barnes, MD, Washington University, St. Louis, the incidence of cervical cancer dropped by 37.7% from 2001 through 2005 to 2010 through 2017 in girls and young women between 15 and 24 years of age.
The U.S. study was published online in JAMA Pediatrics.
“HPV vaccine coverage in the U.S. has improved over the last few years although it was quite poor for many years,” senior author of the U.K. study, Peter Sasieni, MD, King’s College London, said in an interview. “Thus, one would anticipate a lower impact on the population in the U.S., because vaccine uptake, particularly in those aged 11-14 years was so much lower than it was in the U.K.,” he noted.
SEER databases
National age-adjusted cervical cancer incidence and mortality data from January 2001 through December 2017 for women and girls between 15 and 39 years of age were obtained from the combined Surveillance, Epidemiology, and End Results as well as the National Program of Cancer Registries databases. Mortality data was obtained from the National Center for Health Statistics.
Investigators then compared percentage changes in the incidence of and mortality from cervical cancer from January 2001 through December 2005 during the prevaccination years to that observed between January 2010 through December 2017 during the postvaccination years. They also compared incidence and mortality rates in three different cohorts: females between 15 and 24 years of age, those between 25 and 29 years of age, and those between 30 and 39 years of age.
“The older two groups were included as comparison, given their low vaccination rates,” the authors explained. Results showed that, during the same study interval from 2001 through 2005 to 2010 through 2017, the incidence of cervical cancer dropped by only 16.1% in women between 25 and 29 years of age and by only 8% for women between 30 and 39 years of age, the investigators report.
Reductions in mortality from cervical cancer were only strikingly so in the youngest age group of females between 15 and 24 years of age, among whom there was a 43.3% reduction in mortality from 2001-2005 to 2010-2017, as Dr. Barnes and colleagues note.
This pattern changed substantially in women between the ages of 25 and 29, among whom there was a 4.3% increase in mortality from cervical cancer during the same study interval and a small, 4.7% reduction among women between 30 and 39 years of age, investigators add. In actual numbers, mortality rates from cervical cancer were very low at only 0.6 per 100,000 in females between 15 and 24 years of age.
This compared to a mortality rate of 0.57 per 100,000 in women between 25 and 29 years of age and 1.89 per 100,000 in the oldest age group. “These nationwide data showed decreased cervical cancer incidence and mortality among women and girls aged 15-24 years after HPV vaccine introduction,” Dr. Barnes notes.
“Thus, the current study adds to knowledge by quantitatively comparing changes in cervical cancer incidence by age-based vaccine eligibility and providing suggestive evidence for vaccine-associated decreases in cervical cancer mortality,” investigators add.
However, as the authors also point out, while the reduction in mortality from cervical cancer associated with HPV vaccination may translate to older age groups as HPV-vaccinated cohorts age, “the number of deaths and hence the number of potentially averted deaths in young women and girls was small,” they caution, “and efforts to further improve vaccination uptake remain important.”
None of the authors or the editorialists had any conflicts of interest to declare.