Rojanasuphot S, Shaffer N, Chotpitayasunondh T, Phumiamorn S, Mock P,
          Chearskul S, Waranawat N, Yuentrakul P, Mastro TD, Tsai TF
          National Institute of Health, Department of Medical Sciences, Ministry
          of Public Health, Nonthaburi, Thailand.
          Southeast Asian J Trop Med Public Health 1998
          Sep;29(3):443-50

        Since 1990, Japanese encephalitis (JE) vaccine has been part of EPI in
        northern Thailand, where there is a high prevalence of JE and HIV
        infection. To evaluate the immunogenicity and safety of JE vaccine among
        HIV-infected children, we conducted a retrospective study of
        HIV-infected and uninfected children who received 2 doses of JE vaccine
        at 12 months of age. Pre- and post-immunization plasma specimens were
        tested by plaque reduction neutralization for antibody levels to JE and
        dengue(1-4) viruses; titers of > or =10 were considered positive.
        Excluding 5 children with preimmunization antibodies, 5 of 14 (36%)
        HIV-infected children and 18 of 27 (67%) uninfected children had
        positive JE antibody titers after immunization [odds ratio (OR) 0.3,
        p=0.06]; 31% absolute difference [95% confidence interval (CI) 0-61.7%).
        The geometric mean titer of HIV-infected children with positive titers
        was lower than that of control children (15.1 vs, 23.8; p=0.17). No
        significant vaccine-associated adverse events were noted. We conclude
        that primary antibody response to JE vaccine was low among HIV-infected
        children and was approximately half of that seen among uninfected
        children. In endemic areas, HIV-infected children are likely to be at
        risk of acquiring JE despite routine immunization with 2 doses.