We evaluated for persistence of HPV antibody by measuring titers to specific HPV types 6, 11, 16 and 18 at re-enrollment month 24 , 36 and 48 months in addition to month 7 and 12, after initial vaccination. This provided data for immunogenicity among HIV-infected children for approximately 48 months after initial vaccination. We assessed decline over study intervals in HPV type-specific antibodies.
