A Longitudinal Cohort Study to Assess Effectiveness and B-memory Response to the Quadrivalent HPV Vaccine 9 Years Post-vaccination Among HIV-Infected Boys and Girls Ages 9-14 Years in Kenya

Background: Genital Human Papilloma Virus (HPV) infections occur rapidly after sexual debut, and immunosuppressed individuals are at greater risk for incident and persistent infection. HPV vaccine contains virus-like particles (VLP), which are highly immunogenic and induce a robust humoral response that has been demonstrated to confer long term protection from HPV infection and associated disease among HIV-uninfected individuals. The magnitude of type-specific vaccine induced neutralizing HPV antibody responses are diminished among HIV-infected compared to uninfected individuals.

There is no established minimum level of antibody that predicts protection against HPV infection or associated disease, the impact of lower antibody titers among HIV infected individuals on vaccine efficacy is unknown. The risk of HPV exposure persists throughout a person's sexual life and the duration of protection, especially when the vaccine is given in the early adolescent period is critical to vaccine effectiveness. Long lasting memory is characterized by memory B cells and long-lived plasma cells and a QHPV booster dose has demonstrated an anamnestic response among HIV-infected adolescents.

HPV efficacy and effectiveness data for HIV-uninfected individuals has informed the current World Health Organization (WHO) two-dose vaccine schedule. The field lacks data on effectiveness of three dose or two-dose for the HIV-infected adolescents. The current on-going research for single dose schedules gives urgency to the determination of long-term efficacy of three HPV vaccine 231 doses for the HIV-infected adolescent.

Investigators shall recall HIV-infected girls and boys who were previously vaccinated at ages 9-14 years with three doses of the quadrivalent vaccine (QHPV) in 2014 and evaluated for vaccine immunogenicity.

Method: The participants will be assessed for genital warts and genital HPV infection. Type specific HPV DNA will be assessed using genital swabs and genital warts assessed through physical examination among sexually active participants at enrollment, month 6 &12.