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.


1. 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.