AIDS 2014: Young People with HIV Respond Well to Human Papillomavirus Vaccine

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The quadrivalent human papillomavirus (HPV) vaccine worked as well for teens and young adults with HIV as it did for their HIV negative counterparts, according to study findings presented the 20thInternational AIDS Conference last week in Melbourne.

Human papillomavirus is a common sexually transmitted infection that causes abnormal cell growth. High-risk strains, including type 16 and 18, can cause cervical and anal cancer. People typically become infected with HPV shortly after they become sexually active, regardless of HIV status. But HIV positive people tend to harbor more HPV types, are less likely to spontaneously clear HPV, and may experience faster disease progression from dysplasia (abnormal cell changes) to cancer.

An effective quadrivalent vaccine (Gardasil) protects against infection with HPV types 6, 11, 16, and 18; a bivalent vaccine (Cervarix) is effective only against HPV 16 and 18. Studies have shown that the quadrivalent vaccine prevents genital and anal lesions that could progress to cancer. In many countries, HPV vaccination is recommended for girls and boys from pre-adolescence through young adults in their mid-twenties. Beyond that age, most people will already be infected with HPV, but the vaccine may still be beneficial for those who do not carry all the covered types.

Veronica Rainone of the University of Milan and colleagues evaluated the safety and efficacy of a quadrivalent HPV vaccine for HIV positive young people who did not have evidence of infection with the covered HPV types at study entry.

The researchers looked at both humoral immunity, or antibody production, and HPV-specific cell-mediated immune responses carried out by CD4 T-cells and other immune cells. The latter type of immunity may be compromised in people with HIV, especially those who are not on effective antiretroviral therapy (ART).

This prospective, open-label study included 46 HIV positive young women and men (age 13-27 years) and 47 HIV negative control subjects (age 14-27). Participants had well-controlled HIV disease: they had been on ART for at least 10 years, had 2 or more undetectable HIV viral load measurements (<37 copies/mL) during the previous 6 months, and had CD4 counts above 350 cells/mm3. Those with a history of prior HPV vaccination or who had anal or genital warts or other HPV-related lesions were excluded.

All participants received a standard regimen of 3 doses of the Gardasil vaccine at baseline and at 2 and 6 months later.

Blood samples were collected at enrollment and 1 month after each vaccine dose, with follow-up continuing through 18 months. The researchers evaluated humoral immunity as indicated by IgG antibody titers against HPV types 6, 8, 11, and 18. Cell-mediated immunity was determined by T-cell patterns, immune activation, and cytokines production. Participants were monitored for adverse events after each vaccine dose.

Results

The standard three-dose quadrivalent HPV vaccination regimen "generated antibody responses against HPV vaccine types that lasted for at least 18 months among HIV-infected adolescents and young adults and age- and sex-matched HIV-uninfected individuals," the researchers summarized

In addition, vaccination "induced functional activation of the T-cell compartment and primed a robust cell-mediated immunity characterized by Th1-type cytokines and cytotoxic CD8+ T-cell responses up to 7 months after the first vaccine dose," they added. "No adverse effects on markers of HIV-associated loss of immune competence were reported during the study period."

Vaccine-induced cell-mediated immunity did not differ significantly between HIV positive and negative participants, suggesting that "this arm of the immune system is not impaired in HIV-infected adolescents and young adults, thus supporting current recommendations to vaccinate HIV-infected individuals," the investigators concluded.

7/29/14

Reference

V Rainone, D Trabattoni, F Penagini, et al. Efficacy of HPV vaccination in HIV+ adolescents and young adults for the induction of strong HPV-specific humoral and cell-mediated immune responses. 20th International AIDS Conference. Melbourne, Australia, July 20-25, 2014. Abstract WEAB0101.