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The Vaccine Trials Clinical Process |
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Vaccines must be thoroughly tested before they can be called "safe and effective"
for human use. The process by which this testing is carried-out is called a
"Clinical Trials Process." The first tests are called pre-clincal. After preclinical
testing, the clinical trials process may be broken down into 3 distinct steps or
phases called "Phase I," "Phase II" and "Phase III."
The picture below gives a simple idea of what the clinical trials process looks like
for testing the ALVAC vaccine in Protocol 014. HPTU's 014 study
was a Phase-II study.
This means that the vaccine tested in Protocol 014 had already successfully
completed preclinical testing and Phase-I testing. That is, the vaccine had been
tested on very few people and appeared to be safe and give at least some immune
response. Whether the vaccine actually worked to prevent HIV infection was not known
and will not be learned in Phase II. The purpose of Phase II is to learn more about
safety, dosing (how much vaccine to give and when) and more about the immune
response.
If the vaccine looks hopeful after Phase-II testing, it would then proceed to the
next level: Phase III. In Phase III, "Does the vaccine work?" would be the study
question. The VAXGEN study is a phase III trial designed to
test the effectiveness of the vaccine.
If you are interested
in participating in HIV prevention research, please explore our Research page
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