COVID 19 vaccine explained : why so much time?

As laboratories around the world race to develop a vaccine for the novelcoronavirus, many people have volunteered to take part in a controversial testing method called human challenge trials. As of April 27, a global initiative called 1DaySooner had registered 3,817 people in 52 countries who had signed up for such trials.

The method, which involves intentionally infecting volunteers with the novel coronavirus, is being promoted in order to “speed up” the process of preparing a vaccine.

How are vaccines usually developed?

In most regulatory regimes, vaccines take several years to develop, and their development typically proceeds through three phases of clinical trials.

In Phase 1, small groups of people receive the trial vaccine. During Phase 2, the clinical study is expanded and the vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended.