How Were the First COVID-19 Vaccines Developed So Fast?

Past vaccines took years to develop. The first two COVID-19 vaccines were ready in just months—and that was without cutting corners on safety. How is that possible?

A Running Start on Making the mRNA
For one thing, scientists got off to a fast start. The first vaccines use a molecule called messenger RNA (mRNA). This molecule trains your body to recognize a harmless protein on the surface of the virus that causes COVID-19. Your body then builds immune defenses against the protein. That way, it’s already primed to mount a defense if you run into the actual virus in the future.

Also, mRNA vaccines don’t use any real virus. Instead, they are made entirely from chemicals in test tubes or tanks, which saves a lot of time.

Solid Research on Safety, Effectiveness
In the race against a pandemic, there’s an urgent need for speed. But scientists still have to show that new vaccines are safe and work well. That involves the following steps.

Investigational New Drug application. This is the first step in any new vaccine’s journey from the lab to people’s arms. For the COVID-19 vaccines, information about the mRNA technology and data from lab studies were sent to the U.S. Food and Drug Administration (FDA). This application had to be submitted before studies in people could begin.

Clinical trials. These rigorous studies in volunteers are typically done in three phases. For each COVID-19 vaccine, the final, largest phase looked at the vaccine’s safety and effectiveness in tens of thousands of volunteers. After getting their shots, the volunteers were tracked for about two months—long enough to find most side effects.

Emergency Use Authorization request. Once the clinical trials were completed, the results were submitted to the FDA. Then the agency’s scientists and physicians evaluated the evidence. Independent scientific and public health experts weighed in, too. Based on a careful review of the data, the FDA OK’d use of the two mRNA vaccines.

Continued safety monitoring. The FDA and Centers for Disease Control and Prevention (CDC) have several monitoring systems that are constantly on the lookout for rare or long-term safety issues with any vaccine. For the COVID-19 vaccines, they have added extra layers of safety checks, as well. For example, the CDC is using text messaging and web surveys to check in with people after they get vaccinated.

Answering Your FAQs
These are new vaccines for a new disease, so it’s understandable to have questions. Visit our COVID-19 Vaccine FAQ page to learn more. And remember to discuss any concerns with a clinician you trust.