Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. In a long-term follow-up study of an earlier randomized control trial, participants demonstrated sustained immunity 10 years after receiving a 3-dose series of human papilloma virus (HPV) vaccination.

2. There were no HPV-related malignancies or vaccine-related serious adverse events during the follow-up period.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

The risk of HPV-related cancer is lifelong, and therefore any benefit from HPV vaccination needs to be durable across time. This extension study sought to determine the long-term immunogenicity and safety of the 9-valent HPV (9vHPV) vaccine at 10 years following vaccination. The initial study was a multi-center, international study enrolling girls and boys to receive 3 doses of the 9vHPV vaccine. The primary endpoint was serologic evidence of immunity, and secondary endpoints included the development of HPV-related disease, persistent infection, and vaccine-related serious adverse events. At the 10-year follow-up point, the 9vHPV vaccine demonstrated persistent immunologic protection with nearly 95% of subjects remaining seropositive at 10 years. No high-grade HPV-related malignancies or serious adverse events were observed. One important limitation of the study is the lack of a control group. This resulted in the authors interpreting these data in the context of similar prior studies. Overall, this is a well-designed large multicenter study of the long-term efficacy and safety of HPV vaccination and supports the need for ongoing HPV vaccination campaigns in this population.

In-Depth [randomized controlled trial]:

This study was an extension study of “A Phase III Clinical Trial to Study the Immunogenicity, Tolerability, and Manufacturing Consistency of V503 (A Multivalent Human Papillomavirus [HPV] L1 Virus-Like Particle [VLP] Vaccine) in Preadolescents and Adolescents (9 to 15-Year-Olds) With a Comparison to Young Women (16 to 26 Year Olds) (NCT00943722).” The study enrolled girls and boys aged 9-15 years and young women aged 16-26 years to receive 3 doses of the 9vHPV vaccine. At a 10-year follow-up visit, subjects were assessed for anti-HPV6/11/16/18/31/33/45/52/58 antibody response. There was an observed trend towards decreasing immunity with 81.3% to 97.7 percent of subjects seropositive at 10 years. However, the most sensitive assay for evaluating immune response (IgG-LIA) suggested that 94.9% to 100% of participants remained seropositive at 10 years. The differences observed in seropositive rates depending on the assay used is an additional limitation of the study. In females, no cases of high-grade malignancy related to vaccine-targeted HPV strains were observed. One case of cervical intraepithelial neoplasia grade 1 tested positive for HPV 16, 39, and 59 by PCR at month 84 with negative cytology in follow-up. There were no cases of HPV-related diseases in males. Rates of persistent HPV infection were similar to prior 9vHPV studies. There were no vaccine-related serious adverse events throughout the 10-year follow-up.

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