926. Antibody Response to HPV Vaccination in Pediatric and Adolescent People Living with HIV (PLWH). (31st December 2020) - Al Hammoud, Roukaya
Abstract: Background: Immune dysfunction related to HIV infection is associated with an inability to clear HPV infection and may compromise the immunogenicity of quadrivalent HPV vaccine Gardasil® (4v HPV). Methods: Between 2005 and 2017, males and females 7 to 20 years old age, were offered 3-dose 4v HPV vaccine. Plasma IgG titers to HPV 6 (H6), 11 (H11), 16 (H16) and 18 (H18) were measured using multiplex VLP-based ELISA. For the 36 patients, median interval from 1st dose to 2nd and 3rd doses were 73 and 216 days. Plasma sample 1 was collected at median of 91 days after dose 1, sample 2, 169 and sample 3, 740 after respective vaccine doses. A 4th sample was available for 26 patients, median 2327 days after dose 1. Rank-sum test, Χ 2 or Fisher's Exact Test were employed. Results: Before vaccination, 10 (28%) were seropositive to 1 or more HPV types. The baseline seropositives were older than seronegatives (16 years vs 11; p=0.007). After dose 3 all participants had an Ab response to at least 1 HPV type and 32 (89%) were seropositive for 4 HPV types. Seroconversions were H18, 87%; H16 97%; H11, 100%; H6, 97%. Seroconversions after 1 dose of 4v HPV among the baseline seronegatives were 61%, 90%, 86% and 86%, respectively and 22 became seropositive for all 4 types. The 4 baseline seronegative PLWH with partial seroconversion had higher median HIV viral load (VL) compared to baseline seronegative group with full seroconversion (12, 920 vs 101 copies/ml; p = 0.052), but had comparable CD4 counts. The rate of post vaccination seropositivity and baseline to peak titer response for each HPV type was not significantly different for baseline sero-groups. Among baseline seronegative, all 19 sampled distant from vaccination remained seropositive to at least 1 HPV type (84% to 3 or more types) and 6 (32%) became seronegative (sero-reversion). Those showing sero-reversion had higher VL compared to the 14 who remained seropositive (9100 vs 48; p =0.015). Time from last dose of 4v HPV to sample 4, CD4%, age, gender, and race/ethnicity were similar between the groups. Bar Graphs representing Ab response to the 4 HPV types following each dose of 4v HPV vaccine Conclusion: In the complex environment of a pediatric HIV specialty clinic, most PLWH mounted Ab responses to 4v HPV that were durable. H18 was least immunogenic. Patients with higher HIV VL were less likely to seroconvert for all types and were more likely to sero-revert. Disclosures: All Authors : No reported disclosures