COVID-19 vaccine side effects: what to expect after the shot

As COVID-19 vaccines continue to be distributed, the side effects from Pfizer, Moderna and Johnson & Johnson shots are becoming better known. 

Effects can range from mild to severe and differ from your first and second dose, according to the Centers for Disease Control and Prevention. So it’s important to know what you could experience and how to help yourself feel better. 

Pain in the injection site 

Pain in the arm during and after the shot is common. For relief, it’s recommended to keep your arm moving throughout the day, place a clean, wet, cool washcloth over the area and take an over-the-counter pain medication.

For most people, the pain lasts about 24 hours. For others, discomfort can persist several days longer and even become severe. Seek medical attention if the pain gets worse or lasts more than a few days.  


Another side effect many people experience is a headache that can last a few days. Vaccine recipients can take over-the-counter or prescribed medication to relieve it.

Seek medical attention if the headache persists past several days or gets worse after 24 hours.


Being tired after getting the vaccine is common and will pass in a few days. Any longer than that and patients should seek medical attention. 

Many take naps afterwards to sleep off the symptom. 


In most cases, a fever from the vaccine is a normal sign that protection against the coronavirus is building up inside your body.

To help with discomfort it is recommended to drink lots of fluids and dress lightly.

However, if the fever persists after a few days and you begin to worry, seek medical assistance as soon as possible.


Nausea can occur after receiving your vaccine. This symptom should only last a few days and go away on its own.

If not, call your doctor and get immediate medical attention to resolve the issue.  

More information 

According to the CDC, 225 million COVID-19 vaccines have been administered in the U.S. as of Sunday, and as with any vaccine, side effects are likely to occur. 

Kinesiology alumnus Angela Coriddi said headaches, site inflammation, aches and fevers are the most common side effects she’s heard about. 

When the body is first introduced to the vaccine, it has the opportunity to jumpstart the immune system, Coriddi said, so people can see more side effects after their second dose. 

“Their body is prepared and ready to fight that off,” she said. 

Nursing senior Sujita Shrestha said in her experience, side effects vary from person to person. 

One of her friends got the same Pfizer vaccine as Shrestha, and they didn’t have symptoms with the first shot but experienced some from the second. 

“I also know one of our friends, he got like nothing, he seemed to not have any side effects,” she said. 

Coriddi said a person should seek medical attention if side effects last more than a week. If they start experiencing pain in their legs or shortness of breath, a primary care physician needs to be contacted, she said. 

The COVID-19 vaccine might be new, but there are decades of research that have gone on in the background, Corridi said. 

A lot of people don’t understand the symptoms you experience are not from the virus, but your immune system causing those effects, she said. 

Coriddi encourages people to believe in the science and research that has been done. 

“It’s your body revving up its engine so that it can better fight the virus,” she said.  


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