The decision was based on recommendations made by an independent Data and Safety Monitoring Board (DSMB), which analysed early data and concluded that the vaccine
did not prevent HIV
infection nor reduce the amount of virus
in those who became infected with HIV.
Another large study using a T-cell-based vaccine then attempted another enrollment of an 8,500-person trial, to be conducted in Africa and the Americas, going one step further than the Merck adenovirus vaccine.