Participant receives study vaccine

Knowing the Facts

The information below helps healthcare providers understand Vaccine-Induced Seropositivity (VISP) and how they can guide their patients to receive appropriate HIV testing services.

Risk of False HIV Diagnosis

Understanding a study participant's risk:

  • HIV vaccine trial participants can test HIV vaccine-induced seropositive (VISP) even if they don’t have HIV.
  • Tests such as EIA, Western Blot and rapid tests detect HIV antibodies, not the virus, resulting in a potentially false diagnosis of HIV for some HIV vaccine trial participants.
  • We do not know how long the body will retain these antibodies.  Some former study participants have tested VISP even 20 years post-study.

Incorrect HIV Diagnosis

An incorrect HIV diagnosis of a study participant creates significant problems and can:

  • Cause unwarranted distress
  • Result in incorrect HIV diagnosis reporting to public health authorities
  • Compromise a participant’s study “blind”, which is needed for accurate conclusions about a vaccine’s effect on safety, immunogenicity, and efficacy
  • Result in unnecessary treatment with ARVs for parent and child during pregnancy and/or labor and delivery

HIV Testing of Study Participants

In order to get the appropriate test to differentiate VISP from true HIV infection, HIV vaccine study participants are instructed to decline HIV tests outside their study site.

  • Study participants may decline HIV tests due to current or former study participation.
  • Free HIV tests are available through the participant’s vaccine study site or the HVTN VISP Testing Service.  
  • Your patient can give the study site permission to send you test results showing recent HIV status.
  • With your patient’s permission, you may be able to contact the study site directly.

Avoiding an Incorrect Diagnosis

Ways to help your patient avoid an incorrect diagnosis:

  • Inform your patients if HIV testing is indicated for their healthcare.
  • Ask patients whether they have participated in an HIV vaccine trial — even if they don’t fit your perception of HIV vaccine study participants.  
  • Familiarize yourself with HIV vaccine trials happening in your area. If you need HIV test results on a patient who is or was an HIV vaccine trial participant, please contact the participant’s trial site to coordinate the HIV test.