In phase II, the vaccine is administered to many more people than in phase I to collect more information on the vaccine's possible side effects and its effects on the immune system. A phase II trial can last up to a few years, and may involve hundreds of people. Phase III tests the protective benefits of a vaccine in thousands of people. In these large studies, researchers may also identify rare side effects that were not seen in smaller studies. The VTU has participated in Phase I and II trials thus far.
Different studies have different requirements.
Whether a person can enroll in a trial depends on that trial's particular needs. Participants must be in good health and 18-50 years of age. Because a study lasts 1 to 2 years, the volunteer must be planning to live in the area at least that long. Women who are pregnant or planning to become pregnant in the next year may not join a vaccine study. People of color and ethnic minorities are encouraged to apply.