Image by Anna Shvets/Victor Tangermann

Over the course of the summer, the federal government plans to fund three phase III clinical trials for experimental coronavirus vaccines.

Each of the three vaccines will undergo this final phase of testing on about 30,000 human participants, The Wall Street Journal reports, half of whom will receive a vaccine injection and the other half an inert placebo.

The vaccine developed by Moderna Inc will begin its phase III trial in July, followed soon after by those developed by AstraZeneca and Johnson & Johnson. Normally, reaching this point can take years, but coronavirus vaccines have been developed and tested on a vastly-accelerated timeline.

"There's a lot of optimism in our community that a vaccine should be possible, but we are very focused on the fact that that has to be proven in clinical trials," John Mascola, vaccine research director at the National Institute of Allergy and Infectious Diseases, said in a recent conference attended by the WSJ.

There are multiple phases of clinical research necessary before a medication or vaccine is granted regulatory approval. Phase 0 studies how the human body processes a drug. Phase I identifies dangerous side effects and other safety concerns, and phase II trials measure whether the drug actually treats the condition it's supposed to.

Finally, there's phase III: large-scale tests that compare the drug or vaccine against a placebo. Many drugs don't ever reach this final stage of the process, so the fact that three COVID-19 vaccines are already there is a promising sign for the fight to end this pandemic.

"We will want to use the investigative resources of the country as best we can to optimize us getting an answer as quickly as possible," Fred Hutchinson Cancer Research Center vaccine specialist Larry Corey told the WSJ.