COVID-19 vaccine reactions: what you need to know

It's been considered a beacon of hope, the one thing so many have been waiting months for: a safe and effective vaccine against
COVID-19, the disease that has led to severe illness, hospitalizations and the

deaths of more than 400,000 people in the U.S.
However, now that the FDA has granted emergency use authorization for two
mRNA vaccines, and health care providers and older adults across the country have begun to be vaccinated, some people are concerned about receiving the vaccine as they hear stories of possible side effects.
Susan Stone, PhD, senior vice president and chief executive officer of
Sharp Coronado Hospital, wants people to know that the benefits the vaccine provides far outweigh the risk of reactions. She believes this so strongly that she didn't hesitate to get vaccinated herself.
"I have received my first and second dose of the Pfizer vaccine," she says. "I'm pleased to say that I had no reaction to speak of, just a little bit of a sore arm for a day or two."
Common COVID-19 vaccine reactions
Stone is among the
approximately 890,000 Californians who have received the vaccine. Of those, the majority experienced no reaction or a mild to moderate reaction for 1 to 3 days after vaccination.
Commonly reported vaccine reactions include:

• Sore arm (where the vaccine was injected)

• Body aches

• Fatigue

• Fever

• Headache

• Chills

According to the
Centers for Disease Control and Prevention (CDC), these symptoms are normal and are a sign that your immune system is working to build protection against the coronavirus that causes COVID-19.
Taking an over-the-counter pain reliever and fever-reducing medicine, such as ibuprofen or acetaminophen, can help ease the discomfort you may feel. However, do not hesitate to contact your doctor if redness or tenderness where you got the shot increases after 24 hours, or if your side effects are worrying you or do not seem to be going away after a few days.
"The most commonly reported vaccine reactions should not limit anybody from considering getting the vaccine," Stone says. "Certainly, having those side effects is much preferred over having COVID-19 and the potential complications."
Rare severe COVID-19 vaccine reactions
In rare instances, other less common reactions have also been reported after vaccination, such as
anaphylaxis in approximately 5.5 per 1 million individuals vaccinated. According to
one CDC study, more than 80% of the people with anaphylaxis had a history of allergies or allergic reactions. In all instances, this type of severe allergic reaction was successfully treated with epinephrine or personal epinephrine auto-injectors, such as EpiPens. Another rare reaction included swelling after vaccination in people with cosmetic facial fillers, which was successfully treated with antihistamines and steroids.
Though infrequent, vaccination providers like Sharp are prepared for the possibility of such severe reactions. Vaccine recipients are monitored on-site for 30 minutes after being vaccinated. And providers are equipped with appropriate medications and trained to give rapid care and call for emergency medical services.
For people who experienced a severe reaction after receiving their first dose of a COVID-19 vaccine or have a history of allergic reactions to other types of vaccines, the
CDC has issued the following recommendations:

• If you had a severe allergic reaction after getting the first dose of a COVID-19 mRNA vaccine,
  you should not get the second dose.

• If you have ever had a severe allergic reaction to any ingredient in a COVID-19 vaccine or to polysorbate,
  you should not get the vaccine.

• If you have had a severe allergic reaction to other vaccines or injections,
  you should ask your doctor if you should get a COVID-19 vaccine.

• If you have a history of severe allergic reactions not related to vaccines or injections - such as to food, pets, oral medications or environmental allergens -
  you should still get vaccinated.

• If you have had an allergic reaction, such as hives, swelling and wheezing - even if it was not severe - to any ingredient in an mRNA COVID-19 vaccine,
  you should not get either of the currently available COVID-19 mRNA vaccines, or if you had a reaction within 4 hours of your first COVID-19 mRNA vaccine dose,
  you should not get the second dose.

COVID-19 precautions post-vaccine
While Stone and other experts strongly encourage all who are eligible to receive the vaccine do so, she also stresses the importance of continuing to follow existing precautions to prevent the spread of COVID-19.
"Once you get your vaccine, your body is not automatically immune to the virus," Stone says. "So we want to advocate that everybody still practices the prevention habits of wearing a face mask, practicing social distancing, avoiding large crowds, always washing your hands, and just generally making sure that you're doing what you can to prevent being exposed or exposing others to COVID-19."
Experts believe that approximately
75% or more of people in the U.S. need to be vaccinated to reach true
herd immunity, which occurs when a large portion of the population becomes immune to an infectious disease - usually through vaccination - limiting the risk of infection passing from person to person. It is currently estimated that
just 3% of Californians over age 16 have received at least one COVID-19 vaccine dose, the primary reason why maintaining COVID-19 precautions is so important.
"We are certainly seeing the devastation that COVID-19 is causing every day," Stone says. "Every single health care worker is being heroic in their daily actions, and each of us can join them and be a part of the solution by getting vaccinated. I strongly encourage anybody who can get the vaccine to receive it."

Learn about COVID-19 vaccine distribution, safety and more.


This story was updated January 22, 2021, to reflect the most accurate COVID-19 vaccine information.