Clinical efficacy of quadrivalent HPV vaccine persists after 8 years

1. Among preadolescents and adolescents treated with HPV4 quadrivalent vaccine, anti-HPV seropositivity persisted through 96 months post-vaccination.

2. No new significant adverse events were observed over 8 years post-vaccination.

Evidence Rating Level: 1 (Excellent) 

Study Rundown: There are specific strains of the human papillomavirus (HPV), a sexually acquired virus, that are known causes of anogenital neoplasias and condylomata. The quadrivalent HPV6/11/16/18 (HPV4) vaccine was launched in 2006 and works against the 4 most virulent strains of the virus to reduce the incidence of HPV-related diseases. In order to reach patients before they are exposed, adolescent and preadolescent boys and girls are the target population of this vaccine. This is the first long-term study to analyze the safety, efficacy, and immunogenicity of this vaccine in the target patient population. The goals of the study were to evaluate anti-HPV serological levels at 72, 96, and 126 months (this interim publication covers through 96 months) and assess the safety of the vaccine among vaccinated sexually naïve boys and girls. At 96 months, anti-HPV responses were still present, indicating persistent anti-HPV protection from the vaccine. There was 1 vaccine-related adverse event, a cranial nerve VII palsy, which later resolved. Although this is the first HPV4 long-term follow-up study, it is limited by the small sample size, which curtails the ability to detect rare adverse events that may affect the safety profile of the vaccine. Nonetheless, these findings suggest that the HPV4 vaccine remains protective against anogenital neoplasia and condylomata in vaccine recipients after 8 years.

Click to read the study, published today in Pediatrics

Relevant Reading: Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions

Study Author, Dr. Daron Ferris, MD, talks to 2 Minute Medicine: Georgia Regents University, Department of Obstetrics and Gynecology, Augusta, Georgia.

“We demonstrated in over 8 years of follow up of preadolescents and adolescents, the long term immunogenicity, safety and efficacy of the quadrivalent vaccine.  These results should promote widespread vaccination against HPV-related diseases.”

In-Depth [randomized controlled trial]: This study assigned 1661 sexually naïve boys and girls between the ages of 9 and 15 years to receive HPV4 or a saline in a 2:1 ratio at day 1, month 2, and month 6. At month 30, the placebo group received HPV4 vaccine according to the same regimen. The median ages in the early vaccination group (EVG) group and catch-up vaccination group (CVG) were 11.9 years and 14.5 years, respectively, at 30 months. At month 96, anti-HPV6/11/16/18 antibody levels were 88.4%, 89.1%, 96.8% and 64.1%, respectively. Among both EVG females and males, no HPV-related disease was observed after 4.1 years and 2 cases of persistent HPV16 infection of greater than 4 months duration were observed, but both cases resolved within 12 months. Among CVG females, 4 cases of HPV18 infection persisted beyond 12 months and 1 subject was diagnosed with cervical intraepithelial neoplasia 1 (CIN1). There was one adverse event related to the vaccine, a CN VII paralysis of 2.7 weeks duration that resolved after treatment.

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Image: PD

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