Completing HPV Vaccine Doses Has No Added Protective Benefit
Two HPV vaccinations are more effective in warding off cervical cancer than one, but further vaccination appears to offer no benefit.
There was no additional protective effect with a third dose of the human papillomavirus (HPV) vaccine compared with receiving only 2 doses of the vaccine, a study presented at the 48th Annual Meeting of the Society of Gynecologic Oncology has shown.1
To examine the long-term effects and clinical outcomes of varying HPV vaccine doses, investigators analyzed health insurance claims data processed between 2006 and 2015 from 11,335 women aged 9 to 26 years who received at least 1 dose of the quadrivalent HPV vaccine within a 3-year period.
Of those, 1975 patients received 1 dose of the vaccine, 2089 received 2 doses, and 7271 received 3 doses; average age was 21.51 ± 2.67 years, 20.94 ± 2.85 years, and 20.33 ± 2.85 years, respectively. Investigators found that the average time interval to receive subsequent doses was 5.25 ± 4.85 months for patients who had received 2 doses and 8.04 ± 4.07 for patients who had received 3.
With an average follow-up period of approximately 62 months, results showed that single-dose HPV-vaccinated women had a statistically significantly higher cumulative incidence of high-grade cytology, high-grade histology, adenocarcinoma in situ, and invasive cervical cancer when compared with women who had received 2 vaccinations (P =.04).
However, investigators observed no significant difference in outcomes between patients who received 2 doses of the vaccine and those who received 3 doses (P =.17), suggesting that a third dose of the HPV vaccine provides no additional protective benefit with respect to cervical cancer.
Further large prospective studies are warranted to determine the long-term impact of 2 doses of the HPV vaccine vs 3 doses on the incidence and characteristics of cervical cancer.The Centers for Disease Control (CDC) currently recommends 3 doses of the HPV vaccine for persons who initiate the vaccination series at ages 15 through 26 years and for immunocompromised persons, but recommends the use of a 2-dose schedule for girls and boys who initiate the series at ages 9 through 14 years.
Reference1. Zeybek B, Rodriguez A. Comparison of long term impact and clinical outcomes of reduced dose vs standard dose quadrivalent human papillomavirus vaccine in the United States: a database study. Paper presented at: 48th Annual Meeting of the Society of Gynecologic Oncology; March 12-15, 2017; National Harbor, MD.