Antibody titers to the quadrivalent HPV (HPV4) vaccine were lower for all HPV serotypes (6, 11, 16, and 18) in individuals who were infected with HIV perinatally than in individuals who were exposed to HIV perinatally, but uninfected, according to study results published in Clinical Infectious Diseases.
In clinical trials, the efficacy of the HPV4 vaccine from Merck & Co. reached nearly 100%. Further, population-based studies from national registries have suggested that this HPV vaccine has already had an effect in vaccinated youth age 11 to 14 years. However, antibody durability and efficacy in populations that are immunocompromised, like perinatally exposed youths with HIV, is not as well understood. In addition, HIV infection increases the risk for HPV-associated cancer development. However, antibody titer data for perinatally exposed youths with HIV receiving less than 3 doses is limited and there is no published HPV vaccine efficacy data available for perinatally exposed youths with HIV of any age. Therefore, this prospective observational cohort study compared antibody titers with HPV 6, 11, 16, and 18 and the rate of abnormal cytology between perinatally exposed youths with HIV who received the HPV4 vaccine and perinatally exposed youth without HIV.
This study was performed as part of the multicenter Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol. Antibody titer data were available for 310 perinatally exposed youths with HIV and 148 perinatally exposed youth without HIV. When compared with the perinatally exposed youth without HIV, the perinatally exposed youths with HIV had better HPV vaccine coverage with only 10% unvaccinated compared with 22%. Further, 40% of the perinatally exposed youths with HIV and 16% of the perinatally exposed youth without HIV received at least 2 vaccine doses, with females being more likely to receive 3 doses in both populations. Rates of abnormal cervical cytology and genital warts were included in vaccine effectiveness determination. Seroconversion and geometric mean titer against HPV types 6, 11, 16, and 18 were calculated.
Results showed that antibody titers to HPV4 were lower for all serotypes in perinatally exposed youths with HIV compared with perinatally exposed youth without HIV. Seroconversion to HPV 6, 11, 16, and 18 occurred in 83%, 84%, 90%, and 62%, respectively, of vaccinated perinatally exposed youths with HIV (n=310) compared with 94%, 96%, 99%, and 87%, respectively, in vaccinated perinatally exposed youth without HIV (n=148), (P <.05). While geometric mean titers were lower in each category of HPV4 doses received in perinatally exposed youths with HIV compared with perinatally exposed youth without HIV, higher geometric mean titers were associated with younger age, lower HIV type 1 RNA viral load, and higher CD4% at first HPV4 vaccination. However, the most striking result was the high rate of abnormal cytology in perinatally exposed female youths with HIV, regardless of the number of HPV4 vaccine doses received or timing of doses relative to sexual debut. Abnormal cytology occurred in 33 of 56 perinatally exposed youths with HIV and 1 of 7 perinatally exposed female youth without HIV who were vaccinated and were sexually active, which yielded incidence rates (per 100 person-years) of 15.0 and 2.9, respectively.
Overall, the study authors concluded that, “[T]he association between level of immunosuppression and lower [geometric mean titers], as well as observed reduced effectiveness, suggests that [perinatally exposed youths with HIV] children vaccinated at a time of immunosuppression should be revaccinated when immunocompetent.”
By Zahra Masoud
Moscicki AB, Karalius B, Tassiopoulos K, et al. Human papillomavirus antibody levels and quadrivalent vaccine clinical effectiveness in perinatally human immunodeficiency virus- infected and exposed, uninfected youth [publishing online February 21, 2019]. Clin Infec Dis. doi:10.1093/cid/ciy1040