COVID-19 Vaccines: Are There Side Effects?

While there may be some mild-to-moderate symptoms such as fever, fatigue, headache, and arm soreness, experts say the vaccines are safe to take.

Dec. 18, 2020 3   min read

Woman getting the COVID-19 vaccine

The safety and effectiveness of the available COVID-19 vaccines were strongly tested in clinical trials featuring thousands of study participants that found no serious side effects or safety concerns.

During the large Pfizer/BioNTech COVID-19 vaccine trial, “There were no serious side effects that were related to the vaccines,” said Ann Falsey, MD, Infectious Disease Specialist at Rochester Regional Health, one of many local researchers who worked on the Pfizer/BioNTech trial. “That trial was quite large and very carefully monitored. We can say that in almost 45,000 people, it looks very good."

While there may be some mild-to-moderate symptoms such as fever, fatigue, headache, and arm soreness, local experts say the final product is safe to take. 

“Mild side effects are expected after most vaccinations,” explained Dr. Nadia Kousar, Medical Director of Infectious Disease for the Eastern Region of Rochester Regional Health. “They are normal and a sign that the body is building immunity. The commonly reported side effects of this vaccine may affect your ability to do daily activities, but they should go away in a few days.”

Common side effects

According to the U.S. Food and Drug Administration (FDA), the most commonly reported side effects of the Pfizer/BioNTech COVID-19 vaccine typically lasted several days and included:

  • pain at the injection site
  • tiredness
  • headache
  • muscle pain
  • chills
  • joint pain
  • fever

If you experience pain or discomfort, ask your doctor about which safe over-the-counter medications you can take.

Will the vaccines give you COVID-19?

No, none of the COVID-19 vaccines currently in development in the United States contains the live virus that causes COVID-19. While there are several different types of vaccines in development, the goal for each is to teach your immune system how to recognize and fight the virus that causes COVID-19.

Related: Ingredients in a vaccine 

The vaccines in development and approved for emergency use authorization by the FDA will not give you the virus that causes COVID-19.

Things to remember

Side effects may feel like you have an infection, but they are just your body’s way of preparing your immune system, and they should go away after a few days.

Most COVID-19 vaccines require two doses. Get the second dose even if you have symptoms after the first dose unless your provider tells you not to.

It takes time for your body to build up immunity against a virus like COVID-19 or the flu. COVID-19 vaccinations that require two doses may not protect you until up to two weeks after your second dose.


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