What Does It Take to Make an Effective Vaccine?

A primer that doesn’t require a PhD.

The global race is on—COVID-19 vaccine trial testing is underway. And the sound of the starting gun may well have been the 7pm cheers from New Yorkers in lockdown.

Announced in June, NYU Grossman School of Medicine became one of 120 health centers worldwide chosen to conduct a late-stage clinical trial to test a very promising COVID-19 vaccine in thousands of people. This effort builds on successful earlier studies.

If the candidate drug—an mRNA vaccine—succeeds in what’s called the phase 2/3 study, it can be mass-produced and administered to prevent COVID-19 among the general public.

“It is tremendously encouraging to see the early phase of this trial succeed, and to have a lead candidate emerge for global testing,” says Mark J. Mulligan, MD, director of the Division of Infectious Diseases and Immunology and the NYU Langone Vaccine Center.

While the news sounds hopeful, many non-scientists are curious to learn more. What’s an mRNA vaccine? What is “Phase 2/3,” and what follows? Here’s a primer:


With unprecedented collaboration among the federal government, medical community, and biopharmaceutical industry to accelerate research, scientists could bring people an effective COVID-19 vaccine quicker than any other inoculation in history.

Even on the most accelerated timeline, research teams must follow specific protocols and meet strict criteria. These are the steps for a vaccine to reach the masses.


Are COVID-19 trials still enrolling participants at NYU Langone?
Absolutely. NYU Langone is making a great contribution to providing definitive answers about the safety and effectiveness of potential COVID-19 vaccines and treatments. For more information about participating in a clinical trial, please visit