Vax Special Report - September 2007. What immediate implications does the cessation of immunizations in the STEP trial have for the AIDS vaccine field?


Merck and the US National Institute of Allergy and Infectious Diseases (NIAID) recently announced that a Phase IIb clinical trial of MRKAd5, an adenovirus serotype 5 (Ad5)-based AIDS vaccine candidate developed by the company, was not effective. The vaccine candidate did not lower HIV infection rates in individuals who received the vaccine compared to those who received an inactive placebo, nor did it successfully reduce the amount of virus in the blood of those who became HIV infected through exposure to the virus, despite vaccination. This special report explores the issues around this trial.


Vax Online Primer

Published 1 January 2007