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COVID-19 vaccine side effects: What's normal and what to look out for

These are the side effects you can expect after you get the Pfizer, Moderna, Johnson & Johnson or Oxford-AstraZeneca vaccines.

Sarah Tew/CNET
For the most up-to-date news and information about the coronavirus pandemic, visit the WHO and CDC websites.

So far, all three of the available COVID-19 vaccines in the US have a pretty solid track record, especially considering they were fast-tracked. Still, vaccine fears and myths abound, and stories about side effects (exaggerated or not) may make some people more hesitant to get the shot.

Which side effects are par for the course, and which are cause for concern? Here's what to expect if you get the COVID-19 vaccine, whether you get the Pfizer, Moderna or Johnson & Johnson version -- and how you can report side effects to the CDC.

Read more: Do's and don'ts for getting your COVID-19 vaccine

General vaccine side effects

All vaccines have possible side effects with mild to moderate severity. Typical vaccine side effects include local pain, swelling, redness and sometimes bruising at the injection site, as well as fever and tiredness, says Dr. Roshni Mathew, pediatric infectious diseases physician at Stanford Children's Health

With any vaccination, you can expect a bit of pain during and after the injection, says Dr. Thomas Duszynski, director of epidemiology education at Indiana University. He adds that some people may experience chills, fatigue or minor headaches after vaccines. 


Sandra Lindsay, a nurse at Long Island Jewish Medical Center, is inoculated with the COVID-19 vaccine.

Mark Lennihan/Getty Images

Reported COVID-19 vaccine side effects

According to the Centers for Disease Control and Prevention, common COVID-19 vaccine side effects include

  • Injection site pain
  • Injection site swelling
  • Fever
  • Chills
  • Headache
  • Tiredness

Pfizer vaccine side effects

People who get the Pfizer COVID-19 vaccine will likely experience soreness, redness and swelling at the injection site, and potentially chills and fatigue. The Food and Drug Administration lists a couple of additional side effects for the Pfizer-BioNTech vaccine specifically, including muscle pain, joint pain, nausea and swollen lymph nodes. 

The FDA notes that most people experienced these side effects after the second dose of the vaccine

Moderna vaccine side effects

For the Moderna vaccine as well, common side effects remain typical: injection site pain and swelling, chills, fever, fatigue and headache (read the FDA's briefing here). In a company release summing up the Phase 3 clinical trial analysis, Moderna reported that "no serious adverse events were noted in the trial." 

In general, most people report worse side effects after the second dose of the Pfizer and Moderna vaccines, both of which are mRNA vaccinations.

Johnson & Johnson vaccine side effects

The most recently approved COVID-19 vaccine for emergency use, the Johnson & Johnson vaccine -- known as the Janssen vaccine -- only requires one dose as opposed to the two doses required for the Pfizer and Moderna vaccines. 

According to the FDA, the most commonly reported side effects of the Janssen vaccine are headaches, nausea, fatigue, muscle aches and injection site soreness. According to clinical trial data, most people experienced these side effects in the one to two days following injection.

Hives were also reported in six clinical trial participants, one of whom received a placebo shot. One "hypersensitivity reaction, not classified as anaphylaxis," was reported and deemed likely related to the vaccine.

Oxford-AstraZeneca vaccine side effects

This vaccine has not yet received emergency use authorization from the FDA, but some side effects have been reported in clinical trials to date. 

In the clinical trial results published in The Lancet, mild to moderate side effects from the AstraZeneca vaccine were similar to mild side effects from the Pfizer-BioNTech vaccine. Of note, the AstraZeneca vaccine trial was put on hold after a volunteer developed neurological disorder symptoms.

Trials resumed after a safety review confirmed the symptoms were unrelated to the vaccine. It's not uncommon for clinical trials to pause for safety reviews, as illnesses can occur by chance during large, long-term studies. 

There are several other COVID-19 vaccines in the works, and of those that have reported data so far, common side effects include injection site pain and swelling, fever, fatigue, headaches, chills and nausea -- nothing abnormal.  

How to report COVID-19 vaccine side effects

The CDC launched a tool that allows people who have received one or two doses of any COVID-19 vaccine to track and report side effects. The tool, called V-Safe After Vaccination Health Checker, uses messaging and survey functions to automatically check in on people after they get vaccinated. You can sign up for V-Safe on your smartphone after getting the vaccine. You'll need your vaccine info handy, including which type of vaccine you received and the date and time you received it. Using the chat function, you can tell the tool your side effects. Someone from the CDC may call you and ask for more information if you report severe or unusual side effects.

Severe side effects

Few severe side effects from COVID-19 vaccines have been reported, according to the FDA and CDC. In the UK, two people with known, severe allergies suffered allergic reactions after receiving the COVID-19 vaccine, and both recovered. On Dec.15 a health care worker in Alaska experienced a severe allergic reaction to the Pfizer vaccine but has since recovered. She had no previous allergic reactions to vaccines.

During the Pfizer clinical trials, no severe allergic reactions were reported among the 40,000-plus trial volunteers. Although severe allergic reactions are likely to be rare, "It would be important for individuals with known allergies to speak with their health care provider prior to receiving the vaccine," Duszynski says.

The CDC recommends a thorough risk assessment and potential deferral of the vaccine for people with a history of severe allergies to other vaccines, and avoidance of vaccination by people with a history of severe allergies to any ingredients in the COVID-19 vaccines.

Some serious adverse events have been reported from the Johnson & Johnson vaccine, including severe arm pain at and around the injection site that lasted for 74 days in one patient, as well as severe fatigue and weakness lasting three days in one patient. The FDA says these events are likely related to the vaccine, but that they did not occur at frequencies higher during clinical trials than what's probable for the general population (in other words, it's nothing to be alarmed about). 


The FDA is monitoring for additional cases of Bell's Palsy.

Sarah Tew/CNET

COVID-19 vaccine and Bell's Palsy 

People are sounding alarms on social media because four Pfizer-BioNTech COVID-19 vaccine trial participants developed a condition called Bell's Palsy during the trials. Bell's Palsy involves temporary weakness or paralysis in the facial muscles, which certainly sounds scary, but all four volunteers have since recovered (most people with Bell's Palsy recover fully within weeks to three months). 

The FDA briefing on the Pfizer vaccine reports "the four cases in the vaccine group do not represent a frequency above that expected in the general population," so no causal relationship can be determined. The FDA is continuing to monitor for cases of Bell's Palsy as the vaccine is distributed more widely.

Why do vaccines cause side effects?

Side effects like fever, chills and fatigue after a vaccination indicate that your immune system is responding to the vaccine, Duszynski says. "Even if you don't experience these [side effects], it does not mean that your immune system isn't working; it is just working a little more quietly," he says. 

As for bruising, swelling and sensitivity at the injection site, well, your body would likely respond similarly after a needle punctured your skin for any other purpose. These side effects can occur after any vaccine, as well as when people get blood drawn or receive steroid shots or vitamin injections.

How long do vaccine side effects last?


Typically, vaccine side effects only last a couple of days.

Sarah Tew/CNET

Typically, vaccine side effects don't last longer than a couple of days, Mathew says. Some people may experience side effects for several days. Side effects that were related directly to the injection site, like bruising and redness, should subside relatively quickly, while whole-body side effects like fever and headache may last longer.

If you're still having side effects a week or more after you get a vaccine -- COVID-19 or otherwise -- call your doctor or go to urgent care. If you feel the effects are life-threatening (like a severe allergic reaction), seek emergency medical care right away.

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Are there long-term side effects from any of the COVID-19 vaccines? 

At this point, it's way too early to determine whether the COVID-19 vaccines cause long-term side effects, although experts are confident the vaccines are safe. The CDC, WHO, FDA and other health institutions will continue to monitor long-term effects and collect data as more people get vaccinated.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.