Vaccine Safety

The Food and Drug Administration is responsible for making sure that any authorized vaccines are safe and that they work. This process usually takes years to accomplish. This process can take many months, but because of an unprecedented scientific effort, financial support and willing volunteers, researchers were able to test the vaccine on large groups of people much faster than ever before.

Potential Side Effects

When you receive the vaccine, your immune system starts to ward off COVID-19. This can cause some side effects. The majority of patients have had mild side effects. A few patients have experienced moderate reactions.

You may see reactions in the immediate area of where you receive your shot. This includes redness, swelling and pain. Other side effects include fever, fatigue, headache, chills, vomiting, diarrhea and muscle or joint pain. In general, these side effects are like having a flu-like illness. There may be other reactions that are not currently known.

While the side effects can be uncomfortable, it is necessary for you to get both doses of the vaccine. Skipping the second dose will greatly reduce your protection from COVID-19.

You’ll receive information about potential side effects at the time of your vaccination.

Reporting reactions or side effects

The Vaccine Adverse Event Reporting System collects information on reported side effects. Healthcare providers use the system to report vaccination side effects.

Patients and caregivers should report adverse events as well. Even if you are unsure that the vaccine caused the adverse event, we encourage you to report them in any case.

  • If you experience a severe allergic reaction, call 9-1-1, or go to the nearest hospital.
  • Call your health care provider if you have any side effects that bother you or do not go away.
  • Report vaccine side effects to the Vaccine Adverse Event Reporting System (VAERS). You can also call them toll-free at 1-800-822-7967. Please specify which vaccine you received in the first line of box #18 of the report form:
    • Moderna COVID-19 Vaccine EUA or
    • Pfizer-BioNTech COVID-19 Vaccine EUA


V-safe is a CDC smartphone app that monitors the safety of COVID-19 vaccines. You’ll receive text messages and daily symptom surveys to see how you’re feeling after your vaccination. V-safe will remind you to get your second dose if needed. The CDC will follow-up by telephone if you report a significant adverse event. Learn more and register for the app on the CDC website.

Reporting to Manufacturers

Getting a COVID-19 Vaccine

important things to know

Getting a COVID-19 Vaccine

Information on potential side effects, how to report side effects to and other things to keep in mind.

Dr. Michael Lauzardo Answers Questions About Vaccine Safety and Effectiveness

Dr. Lauzardo Discusses Side Effects

Listen to UF Health expert Dr. Michael Lauzardo discuss current side effects from the vaccine trials.

Common Questions about vaccine safety

If I get a vaccine, do I still need to wear a mask and practice physical distancing?

Yes. Vaccines may boost your immune system, so it is ready to fight the virus if you are exposed, but it is not yet fully understood whether vaccinated people might still be able to transmit the virus. Initially, we will not have enough supplies globally to vaccinate everyone who wants the vaccine, and the virus will still be transmitted. It is important for you to continue wearing a mask and following other precautions, such as practicing physical distancing and frequently washing your hands, to help reduce your chance of being exposed to and spreading the virus.

How do you counsel people to feel safe about the vaccine?

Can children get the COVID-19 vaccine?

In early clinical trials, all participants were at least 18 years of age. At this time, the COVID-19 vaccine is not recommended for children under the age of 16. More information will be available from vaccine manufacturers and the CDC in the future.

Who should I contact if I have questions about whether to receive the vaccine?

You should contact your primary care physician to discuss your concerns. Additionally, the State of Florida has set up a 24-hour hotline that is dedicated to answer your questions or concerns about the vaccine. The number is 866-779-6121. The call center is open 24 hours a day, 7 days a week.

What is Emergency Use Authorization?

The FDA can issue an Emergency Use Authorization (EUA). These are issued for public health emergencies. For the FDA to issue an EUA for COVID-19 vaccines, safety and effectiveness of the product must be demonstrated through a phase 3 clinical trial, and certain criteria must be met, including that there are no approved and available alternatives. In December, the FDA approved EUAs for the Pfizer-BioNTech and Moderna COVID-19 vaccines.

CDC Information

Vaccine Testing and the Approval Process

The Centers for Disease Control and Prevention offer resources describing how vaccine development and testing occur.

COVID 19 Testing in the Emerging Pathogens Institute