Objective: To evaluate the influence of a human immunodeficiency virus (HIV) vaccine given to uninfected volunteers on the interpretation of serodiagnostic HIV test results.
Design: Retrospective cohort study.
Setting: 5 AIDS Vaccine Evaluation Units funded by the National Institute of Allergy and Infectious Diseases.
Participants: The first 266 healthy adult volunteers (aged 18 to 60 years) who did not have HIV infection and whose history suggested that they were at low risk for acquiring HIV infection.
Measurements: HIV antibody was measured by enzyme-linked immunosorbent assay (ELISA) and Western blot test, the results of which were interpreted on the basis of four different published criteria.
Results: At some time during the first 12 months of the vaccine studies, 68% of volunteers were positive for HIV antibodies by ELISA. Depending on criteria used to interpret Western blot test results, 0% to 44% of volunteers had positive results that might have caused them to be incorrectly labeled as HIV infected.
Conclusions: Significant social risks to volunteers participating in HIV vaccine studies were identified. Persons interpreting HIV serodiagnostic test results must consider that an HIV vaccine can cause a positive result in persons who are not infected.