Cedars-Sinai Blog

COVID-19 Vaccination Side Effects: What You Need to Know

A patient receiving a COVID-19 vaccination from a healthcare professional.

If you're planning to get the COVID-19 vaccine, or you've already got your appointment, we're excited for you! It's one of the best things you can do to protect yourself and others.

For those who are worried about potential side effects of the vaccine and might be hesitant about scheduling a vaccination appointment, we spoke to Cedars-Sinai's Dr. Caroline Goldzweig for answers to common questions about what to expect after your shot.


"It's normal to feel some side effects, but it's just as normal not to!"

What should I expect after getting my COVID-19 vaccination?

Caroline L. Goldzweig, MD and Chief Medical Officer at Cedars-Sinai Medical Care Foundation

Caroline L. Goldzweig, MD

Dr. Caroline Goldzweig: You can expect to feel relieved! Lots of people feel emotional after getting the COVID-19 shot. It's the light at the end of the pandemic tunnel, and you just took a huge step in protecting yourself—and others.

Why do some people get side effects after the vaccine while others do not? If I don't get any, does that mean my immune system isn't reacting like it should?

CG: We don't know exactly why some individuals have a stronger reaction than others. Fatigue, muscle aches, fever or pain at the injection side are signs that your immune system is getting in gear, so it shouldn't worry you if the symptoms last a few days.

In some people, the immune system responds without those reactions or with milder ones. It's normal to feel some side effects, but it's just as normal not to!

If I feel sick after the shot, what medications can I take?

CG: Most people can safely take Tylenol (acetaminophen) or medicines like Motrin and Aleve to deal with symptoms such as fever, chills and body aches. It is not generally recommended to pre-medicate before getting the vaccine but to wait to see if you have any symptoms.

Tylenol is generally preferred but you should check with your doctor for specific instructions. Most importantly, remember that any vaccine side effects should pass within 72 hours, and likely sooner. Serious adverse effects, or effects that last longer than three days, can be reported to the CDC's vaccine monitoring program.

Have there been many serious side effects so far?

CG: Very few people have had strong reactions to any of the COVID-19 vaccines on the market. The most serious side effect is an allergic reaction called anaphylaxis, which has occurred in a small number of people.

While anaphylaxis is rare, you will be asked to stay at the vaccine site 15 minutes after getting your shot so the staff can make sure you're OK. For those who have a history of allergic reactions to medications or other vaccines, you will be asked to stay 30 minutes. If you have a known allergy to any of the ingredients in a vaccine, you should not get that shot.

After I get vaccinated, should I expect to continue following safety protocols?

CG: For now, we should all expect to keep up precautions like wearing a good mask and maintaining physical distance when we are in public or in contact with people outside our families. But you can also expect things to start getting better as more and more people get their shot.

Follow the CDC's guidance. And remember that all the vaccines on the market work and are safe—take whichever vaccine is offered! You can get vaccinated with confidence—and I hope you do.

If I have COVID-19, should I wait 90 days after symptoms clear up before getting my shot?

CG: No, but you can safely delay getting the vaccine that long after being sick with COVID-19. That's because you'll have immunity to the disease for several months.

With vaccine supply limited, we hope to get the shots to people who don't have any immunity to COVID-19 and who need it the most. If you don't want to wait 90 days, there's no risk in getting the shot sooner. Just wait until you don't have any more symptoms.

Your body is already working hard to fight the virus, and it's best to get the vaccine when you are at your strongest. Getting the vaccine also doesn't help you recover faster if you're already sick with COVID-19—it's to prevent future illness only.

After I get the COVID-19 vaccine, do I need to wait before getting any other shots?

CG: It's wise to wait at least 14 days after receiving a COVID-19 shot before getting other vaccines—unless you're in an emergency situation. If you cut yourself with something potentially dirty and you're overdue for a tetanus booster, for example, get that shot if a healthcare professional advises you to.

For vaccines that aren't urgent, it's best to give your body a bit of time after the COVID-19 vaccine. That's to reduce your risk of feeling unwell, or of interfering with the immune response to the other vaccine. The opposite is also true: If you've gotten other vaccines, ideally wait 14 days before getting the COVID-19 vaccine.

Do I need to delay a mammogram after getting my shot?

CG: If you are due for a mammogram, we don't recommend delaying, but you should let the screening professionals know that you've just had the vaccine.

That's because the shot can cause swelling in the lymph nodes in the armpit—a harmless reaction that could be mistaken for nodes that are swollen because of cancer. If your healthcare professional knows you've recently been vaccinated, it will help them interpret the images.