HIV vaccine-induced sero-reactivity: a challenge for trial participants, researchers, and physicians

Abstract

Antibody-inducing vaccines are a major focus in the preventive HIV vaccine field. Because the most common tests for HIV infection rely on detecting antibodies to HIV, they may also detect antibodies induced by a candidate HIV vaccine. The detection of vaccine-induced antibodies to HIV by serological tests is most commonly referred to as vaccine-induced sero-reactivity (VISR). VISR can be misinterpreted as a sign of HIV infection in a healthy study participant. In a participant who has developed vaccine-induced antibodies, accurate diagnosis of HIV infection (or lack thereof) may require specialized tests and algorithms (differential testing) that are usually not available in community settings. Organizations sponsoring clinical testing of preventive HIV vaccine candidates have an ethical obligation not only to inform healthy volunteers about the potential problems associated with participating in a clinical trial but also to help manage any resulting issues. This article explores the scope of VISR-related issues that become increasingly prevalent as the search for an effective HIV vaccine continues and will be paramount once a preventive vaccine is deployed. We also describe ways in which organizations conducting HIV vaccine trials have addressed these issues and outline areas where more work is needed.

Keywords: HIV; VISP; VISR; Vaccine; Vaccine-induced sero-positivity; Vaccine-induced sero-reactivity.

Fig 1

Results of commonly used serology-based tests are inconclusive with regard to HIV infection status in participants with VISR. The tests may not differentiate between vaccine-induced antibodies and antibodies present as a result of an HIV infection. Trial participants with VISR may be incorrectly perceived as being HIV-positive. Because the person with vaccine-induced antibodies could still become infected with HIV, VISR-status may lead to delayed diagnosis of infection.