Michael J. Silverberg
A recent study confirmed that catch-up vaccination with the HPV vaccine is effective in women up to age 20 years, however, researchers said more research is needed exploring the effect in women aged 21 to 26 years because there was no significant protection detected.
In the United States, HPV vaccination is recommended for girls aged 11 to 12 years. For girls who did not receive the vaccination, catch-up vaccination is recommended to be completed between ages 13 and 26 years. Fourteen HPV types are considered high risk for causing cancer, including types 16 and 18, which cause most cervical cancers. According to the CDC, it may take years or even decades for cancer to develop in an infected patient.
“Very little evidence exists regarding protection of the HPV vaccine against long-term outcomes such as cervical precancer and cancer,” Michael J. Silverberg, PhD, MPH, a research scientist at Kaiser Permanente Northern California, told Infectious Disease News. “The reason is because the first HPV vaccine was introduced in the U.S. in 2006, so we are now starting to see vaccinated girls and women enter cervical cancer screening programs, which start at age 21. Kaiser Permanente offered a unique opportunity to study this question given the established cervical cancer screening program, our large size, and comprehensive capture of key data.”
For their study, Silverberg and colleagues included 4,357 women enrolled in Kaiser Permanente North California with cervical intraepithelial neoplasia of grade 2 or higher (CIN2+) or grade 3 or higher (CIN3+) who were aged 26 or younger when the HPV vaccine was introduced in 2006. For each case, researchers age-matched five controls without CIN2+ or CIN3+.
Among the women enrolled in the study, 2,837 had received at least one dose of the HPV vaccine between 2006 and 2014.
Silverberg and colleagues found that the strongest protection against CIN2+ and CIN3+ was identified in women who received three vaccine doses and had received their first dose between ages 14 and 20. No significant protection was discovered in women who received their first dose at age 21 and older, or for women who received fewer than the full three doses.
There was a significantly reduced CIN2+ risk for women who received at least three HPV vaccine doses but not in women who received one or two doses, according to the study.
During the study, 23 women were diagnosed with cervical cancer and only three of those women had prior HPV vaccination. All three women had received at least three doses, however, all were age 21 years or older at the time of their first dose.
“Our primary goal was to provide evidence regarding the most effective ways to protect women from the long-term consequences of HPV infection,” Silverberg said. “Our results support early vaccination with the full three-dose series for girls and women who start the vaccine at older ages. More research is needed as more HPV-vaccinated women become age-eligible to be screened for cervical cancer.” – by Caitlyn Stulpin
Disclosures: The authors report no relevant financial disclosures.