production of immune system T cells that can kill HIV-infected cells.

Between 2004 and 2007, the National Institutes of Health conducted a STEP study.
The STEP Study is the name of a clinical trial to test an experimental human immunodeficiency virus (HIV) vaccine that aimed to stimulate production of immune system T cells that can kill HIV-infected cells. The study enrolled 3,000 participants at sites in Australia, Brazil, Canada, the Dominican Republic, Haiti, Jamaica, Peru, Puerto Rico, and the United States.
On the basis of its first evaluation of vaccine efficacy, the findings were as follows:
There were 24 cases of HIV infection among the 741 volunteers who received at least one dose of the investigational vaccine.
There were 21 cases of HIV infection among the 762 volunteers who were vaccinated with a placebo.
In volunteers who received at least two vaccinations:
There were 19 cases of HIV infection among the 672 volunteers who received the investigational vaccine.
There were 11 cases of HIV infection among the 691 volunteers who received the placebo.
The investigators of the vaccine trials have decided to cease immunizations and are contacting study volunteers to inform them of the developments.
Prior to beginning this study, how would you have described the risks and benefits of the study to participants? Share your thoughts and discuss the ethical issues surrounding this study at the beginning and at the time the decision was made to terminate the study.

Evaluation Criteria:
Provided at least one risk and one benefit.
Discussed at least two ethical issues at the beginning and two ethical issues at the end of the study.
Justified answers with appropriate research and reasoning by using examples and references no more than 5 years old