2524. Prevalence and Associated Factors of Seroprotection Against Japanese Encephalitis Virus Among HIV-Infected Thai Adolescents Stable on Combination Antiretroviral Treatment

Background To determine the prevalence and associated factors of seroprotection against Japanese encephalitis (JE) virus among HIV-infected adolescents stable on combination antiretroviral treatment (cART). Methods A multicenter seroprevalence study was conducted in Thailand. Perinatally HIV-infected adolescents who aged 11–25 years, had previous evidence of severely immune suppression (CD4 < 15% or < 200 cells/mm3), were currently stable on cART (CD4 > 350 cells/mm3 for > 6 months or CD4 > 200 cells/mm3 with viral suppression [VS; plasma HIV RNA < 50 copies/mL] for > 12 months), and had completed a 3- or 4-dose series of mouse brain-derived inactivated JE vaccine (MBDV) during childhood were enrolled. Adolescents who had clinically or serologically confirmed recent JE virus infections, or received immunosuppressive agents or blood components within 6 months were excluded. Plaque reduction neutralization (PRNT50) assay was conducted to assess neutralizing antibodies to JE virus, and titers of ≥ 10 were considered seroprotective. Logistic regression analysis was performed to identify associated factors of JE seroprotection. Results Of 98 eligible adolescents, 54% were female, a median age was 19 years, and 11% were overweight. Ninety-five percent and 5% of adolescents received 3 and 4 doses of MBDV during childhood, respectively. A median duration since the last dose of MBDV was 16 years. At enrollment, 71% were on NNRTI-based cART regimens, a median cART duration was 13 years. A median current CD4 was 29%, and 89% had VS. Seroprotection against JE virus was identified in 28 (29%) adolescents; of whom, the geometric mean titer (GMT) of neutralizing antibody was 64 (95% CI: 39–106). Proportion of adolescents with JE seroprotection and GMT of neutralizing antibodies to JE virus slightly decreased over time after the last immunization (Figure 1). In a multivariable logistic regression analysis, seroprotection against JE virus was associated with younger age and greater current CD4 count (Table 1). Conclusion The majority of our perinatally HIV-infected adolescents did not maintain seroprotection against JE virus although having completed a series of MBDV during childhood. JE revaccination is an important tool for disease prevention in these adolescents who live in JE endemic areas. Disclosures All authors: No reported disclosures.