Both OPV and IPV can elicit neutralizing antibody responses in HIV-positive children and adults, and in patients with CD4 counts <300 cells/μL . The seroprevalence of poliovirus-neutralizing antibodies varies among HIV-positive adults. HIV-positive patients born and resident in the UK since 1962 have generally received a complete 5-dose vaccine course as part of routine childhood immunization. High prevalence rates, comparable to those in normal controls, have been reported in some cohorts. However, in a seroepidemiological study of Italian drug users, those with HIV infection were more likely to lack protection, with 34% seronegative for poliovirus type 3 and 11% lacking neutralizing antibodies to all three virus types . OPV is contraindicated in patients with HIV and their contacts. IPV can be administered safely to immunocompromised adults.