STEP STUDY
The Step Study was testing whether a vaccine that used a disabled common cold virus to deliver HIV information to the body's immune system could effectively prevent HIV infection, or delay disease in someone who did become infected.
This study enrolled 3,000 HIV negative men and women across the Americas. The people who enrolled were at high risk for HIV infection, and were offered regular HIV testing and counseling throughout the study.
Vaccinations in the study were stopped in September, 2007 because there was no evidence the vaccine was offering protection against HIV. Later analysis showed that a small group of men in the study, those men were uncircumcised and had been previously exposed to the cold virus used in the making of the vaccine, may have been at slightly increased risk of acquiring HIV after vaccination.
Further analysis is happening now to help investigators better understand these results. Steps are being taken to protect participants in future vaccine studies.
All of the study participants were asked to keep coming for study visits to help investigators understand how the vaccine was working in their bodies, and those participants enrolled into a study called HVTN 504. Data is still emerging from these studies.
A Letter to Step Study Volunteers
Efficacy Results from the Step Study
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