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How do we know emergency “fast-tracked” vaccines are safe?

Common Questions-group of adolescents

A fast-tracked vaccine is one that goes through a process of rapid development and review to help get new vaccines to the public earlier.

There is a history of safe “fast-tracked” vaccine development, from Ebola vaccines to COVID-19 vaccines. Fast-tracked vaccines are considered emergency vaccines. Even though they are developed quickly, they still have to meet the same safety requirements as vaccines that are developed in non-emergency situations.source: 1

It is important to understand how these vaccines are developed and how we know they are safe because we may need another fast-tracked vaccine in the future.

  • Fast-tracked vaccines are usually not new. Vaccines helped control the 2014–2015 West African Ebola outbreak. Experts started developing those vaccines as early as 1977, soon after discovery of the Ebola virus.source: 2 The same was true for the COVID-19 vaccines: Scientists had been working on coronavirus vaccines since 2002. The mRNA technology for some of the COVID-19 vaccines has been researched since the 1970s.source: 3,source: 4,source: 5

  • Safety is never compromised. Vaccines that are developed quickly for emergencies must go through the same rigorous safety evaluations that all other vaccines go through. For a vaccine to be authorized or approved for public use, clinical trials must prove the vaccines are safe.source: 6,source: 7

    Long-term health effects from vaccines are very rare. If they happen, they almost always emerge within 45 days after vaccination and clinical trials closely monitor health effects for at least 60 days. This means that we know very quickly whether fast-tracked vaccines are safe for public use, even though they are developed more rapidly.source: 8

  • Fast-tracking requires a lot of money. The main reason we don’t fast-track all vaccines is because it is very expensive. Fast-tracking generally requires the same number of scientists and the same level of resources as routine vaccine development, but the timeframe is compressed, from as long as a decade to as short as several months. That requires a significant amount of money. Fast-tracked vaccines still must go through FDA review before they are authorized or approved, but they go to the front of the line for steps such as data review and analysis.source: 9,source: 10

Key Evidence

  • Fast-tracked vaccines are not experimental or untested. There are no experimental or untested vaccines available to the public. All vaccines, whether they are FDA-approved or available temporarily through an EUA, must go through at least three testing phases in clinical trials before they can be made available to the public.source: 11

    Although FDA sometimes grants EUA to fast-tracked vaccines, EUA and fast-tracking are not the same. Fast-tracked vaccines are pushed quickly through the development and testing phases to help get vaccines to the public faster. EUA, on the other hand, is when FDA temporarily allows the use of a vaccine that has been tested and found safe but is not yet approved. Fast-tracking and EUAs are different tools, but they both help get life-saving vaccines out to the public as quickly as possible.source: 12,source: 13

  • EUA vaccines are safe. EUAs are used during public health emergencies to help save lives by getting safe vaccines to the public quickly. The safety of a vaccine given an EUA must be proven in clinical trials, just like in the process for full FDA approval. But what is different is the bar for effectiveness. In full FDA approval, a vaccine must be proven to be effective. In an EUA, there must be reasonable belief the vaccine will be effective.source: 14
  • EUA vaccines still need full FDA approval once the emergency is over. An EUA is a temporary authorization that is given during emergency situations only if the vaccine is shown to be safe. Once the emergency is over, the vaccine must go through the regular FDA review process to receive full approval.source: 15
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A Deeper Dive: Why fast-tracked vaccines are so important

Fast-tracked vaccines are important because they are a powerful way to help protect people from disease and save lives. For example, less than a year after the first reports of COVID-19 cases, the number of reported deaths from COVID-19 increased to 1.8 million globally.source: 16 If the COVID-19 vaccines had not been fast-tracked, those numbers would be even higher. Researchers have determined that COVID-19 vaccines have prevented an estimated 14.4 million deaths around the world.source: 17

This is why fast-tracked vaccines matter.

When a disease is both highly contagious and very deadly, we need immune people to stop its spread. Once the vaccines were available, deaths plummeted among vaccinated people and slowed the spread of COVID-19. About 8 in 10 people in the United States have gotten at least one dose of a COVID-19 vaccine.source: 18 It was only after most people got vaccinated in the United States that we were able to go back to school, work, and the things that matter to us. While vaccinated people may still get COVID-19, they are far less likely to get seriously sick and die than those who are unvaccinated.source: 19

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More information

Still have questions? Talk to your child’s doctor, nurse, or pharmacist.

Sources

  1. FDA: Fast Track
  2. FDA: Fast Track
  3. Therapeutic Advances in Vaccines and Immunotherapy: Clinical Development of Ebola Vaccines
  4. UCLA Health: The Fastest Vaccine in History
  5. Johns Hopkins, Bloomberg School of Public Health: The Long History of mRNA Vaccines
  6. UCLA Health: The Fastest Vaccine in History
  7. Johns Hopkins, Bloomberg School of Public Health: The Long History of mRNA Vaccines
  8. The Washington Post: Transcript: The Path Forward: Combating COVID-19 with Anthony S. Fauci, Director, National Institute of Allergy and Infectious Diseases
  9. FDA Vaccine Facts: The Path for Vaccines
  10. NIH: Fast Tracking—Vaccine Safety, Efficacy, and Lessons Learned: A Narrative Review
  11. NIH: Fast Tracking—Vaccine Safety, Efficacy, and Lessons Learned: A Narrative Review
  12. FDA: Fast Track
  13. FDA: Emergency Use Authorization for Vaccines Explained
  14. FDA: Understanding the Regulatory Terminology of Potential Preventative and Therapeutic Drugs for COVID-19
  15. FDA: Understanding the Regulatory Terminology of Potential Preventative and Therapeutic Drugs for COVID-19
  16. WHO: The true death toll of COVID-19: estimating global excess mortality
  17. Journal of Paediatrics and Child Health: Lives Saved by COVID-19 vaccines
  18. CDC Data Tracker: COVID-19 Vaccinations in the United States
  19. CDC: Overview of COVID-19 Vaccines
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