Many candidate vaccines have been developed and tested in various animal models.

But the utility, availability and cost of the most promising candidate vaccine under development is also a question mark.

However, new candidate vaccines continue to move through the development pipeline.

In the Nature report, the scientists said that the candidate vaccine had stimulated two important immunological reactions.

The candidate vaccine had no side effects, according to the report.

Specifically, candidate vaccines that induce one or more of the following are being sought:

It was exactly the information Merck needed for studies to determine whether a candidate vaccine was effective.

Meanwhile, scientists would start testing any other strain that looks more promising as a candidate vaccine.

The ability to grow rotavirus in culture accelerated the pace of research, and by the mid-1980s the first candidate vaccines were being evaluated.

The candidate vaccine went from the research bench into clinical trials in less than 6 months.