What to know about COVID-19 vaccine side effects

Most side effects of the vaccine are relatively minor and typically last a few days or less, according to the Centers for Disease Control and Prevention. Many people experience no side effects at all, while others experience more intense side effects after their second shot.

Common side effects are pain, redness and swelling at the site of the injection. Throughout the body, people going through the vaccination process could experience headaches, tiredness, muscle pains, chills, fever and nausea, health officials have said.

Not at all. A side effect or reaction to the vaccine is not necessarily a negative result. Health officials say it likely indicates that the body is building protection or immunity against the virus.

"The vaccine, because you’re giving it in the arm, it gives a systemic reaction," said White House COVID-19 adviser Anthony Fauci during a recent interview with MSNBC. "You know that because sometimes after the second dose you feel a little achy, a little chilly, which means the immune system is really getting revved up."

While very rare, some individuals have experienced severe allergic reactions, called anaphylaxis, to the vaccine, most often people known to have had severe vaccine reactions in the past. Signs include trouble breathing; swelling of the face and throat; rash; and low blood pressure, the CDC said.

If someone had an immediate allergic reaction after getting a shot of a COVID-19 vaccine, health officials said they should not get a second shot of that vaccine, even if their allergic reaction was not severe enough to require emergency care.

The CDC said patients should speak to their doctors about over-the-counter medication such as ibuprofen, acetaminophen, aspirin or antihistamines for any pain and discomfort experienced after getting vaccinated. It is not recommended that patients take these medicines before vaccination to try and prevent side effects.

To reduce pain and discomfort at the injection site, health officials recommend applying a clean, cool, wet washcloth over the area and moving your arm around. To reduce discomfort from fever, drink plenty of fluids and dress lightly, the CDC said.

Health officials say having a reaction to the vaccine doesn't mean that the patient is having a bad immune response. Most likely, officials said, it means those people's immune systems are more sensitive than others'.

In most cases, discomfort from pain or fever is a normal sign that your body is building protection. But health officials suggest contacting your health care provider if the redness or tenderness where you got the shot gets worse after 24 hours, or if your side effects do not go away after a few days.