How does the FDA approve vaccines?

How does the FDA approve a new vaccine?

The process of getting a vaccine approved for use in the general public is no picnic and can take several years. In the United States, vaccines are regulated by the Food and Drug Administration’s Center for Biologics Evaluation and Research. The FDA works to ensure that all new vaccines on the market are safe, effective, and have minimal side effects by carefully monitoring each stage of testing.

Vaccines must be FDA approved for clinical testing in humans

Vaccines that appear promising in pre-clinical trials, where the vaccine is tested on tissue samples and in animal models, have to be approved for a clinical trial before they can be tested on humans. A sponsor for such a clinical trial must submit an Investigational New Drug application to the FDA, which describes the vaccine, how it’s made, how it’s been tested for quality control, and the protocol the researchers propose for testing the vaccine in humans.

Three phases of clinical trials

If the application is approved, vaccine clinical trials usually happen in three phases. Phase 1 is usually a small trial — 20 to 80 subjects — that’s mostly focused on testing the safety of a vaccine and seeing how strong of an immune response it provokes in humans. During a Phase 2 trial, the vaccine is tested on a larger group of participants, usually several hundred, and different doses of the vaccine are tested to find out which is the most effective. Finally, Phase 3 trials test the vaccine on thousands of people, and include testing the vaccine against a placebo, studying the long-term efficacy of the vaccine, and watching for very rare side effects.

Experts weigh in on efficacy and safety

The FDA monitors the progress of these trials, and will halt trials or request additional information or research if there are any concerns about the vaccine’s safety or effectiveness. If the vaccine completes all three phases of clinical development, the manufacturer must submit a Biologics License Application. This provides the FDA reviewer team, which includes medical, biology and chemistry experts, with all of the safety and efficacy information they need to assess the risks and benefits of the vaccine and to decide whether or not they recommend it be approved. The manufacturing facility also has to be inspected so the FDA can examine the production of the vaccine in detail.

Next, the FDA and the vaccine’s sponsor present their data to the Vaccines and Related Biological Products Advisory Committee, which is a non-FDA expert committee of scientists and physicians who provide feedback to the FDA on the vaccine.

After approval

Once a vaccine is approved, the FDA continues to oversee its production, with periodic facility inspections and tracking of the quality control performed by the manufacturer. The FDA also maintains the Vaccine Adverse Event Reporting system, allowing healthcare providers and patients to report extremely rare health events that may be a result of receiving the vaccine.

This controlled, step-by-step process allows researchers, manufacturers, the FDA, and healthcare providers to work together to ensure that vaccines are safe and effective before they are distributed to the public.

Watch part one: How do vaccines work?

Watch part two: What are the different types of vaccines?

Watch part three: How are vaccines made?

How was the COVID-19 vaccine developed so quickly? Learn more.

Watch part five: What is an mRNA vaccine?