The largest trial yet for a potential COVID-19 vaccine began on Monday, as drug company Moderna began providing the first of an anticipated 30,000 volunteers with shots of its candidates. This is a blind trial, wherein some participants will get the vaccine and some will get placebos. Each participant will get two doses, and researchers will study them to see which group suffers more actual infections as they proceed about their lives as they would normally.
There are more than 70 anticipated trial sites across the U.S. for this study; the first to begin vaccinating the volunteer participants is located in Savannah, Georgia. The makeup of the overall group of participants is intended to study not only geographical distribution, covering regions hard-hit by the virus and those with less severe outbreaks, but also to represent a wide sample when it comes to demographics of those participating.
The Moderna trial is being undertaken in partnership with the U.S. National Institutes of Health (NIH), and represents one of the fastest development cycles of a vaccine ever. Just around two months after work was begun on the Moderna vaccine, it was already being tested in humans for the first time, and early data from its Phase 1 tests (which were on a much smaller scale) have shown promising indications that it does indeed provide some infection protection -- though large-scale tests like this are definitely required before anyone can say anything definitive about its efficacy.
In addition to making sure that the vaccine is actually effective as a vaccine, this large-scale test is intended to prove it's safe to take. Early results indicated some side effects, but again, it's impossible to say anything definitive about downsides until you test at scale.
Other trials are also making quick progress, including one for a vaccine developed by the University of Oxford. Moderna has previously said that experimental versions of the vaccine might be available on an emergency basis for healthcare workers by this fall, if all goes to plan.