What Happens After You Get Vaccinated? 

Janet Tiberian Author
By Janet Tiberian, MA, MPH, CHES
February 12, 2021
I'm Vaccinated for COVID. Do I Still Have to Wear a Mask?

If you’re already vaccinated for COVID-19, you may feel like you’ve won the lottery. For those who got their shots early, that’s not a bad comparison. Through mid-February nearly 40 million Americans had received at least one dose of a vaccine. 

But if you have been vaccinated or are about to be vaccinated, there’s some things you need to know about life after the Coronavirus vaccine. Unfortunately, it looks a whole lot like life before the vaccine. 

Side Effects 

After you receive one of the vaccines produced by Moderna and Pfizer, you may experience side effects, according to the Centers for Disease Control and Prevention.  

Common side effects include localized pain, swelling and redness where the shot was administered. During phase 3 trials, about half the participants who received the vaccines experience headaches and fatigue. A third had chills and muscle pain. These side effects tend to be more pronounced after the second dose. 

The good news is these side effects subsided after a day or two — and the side effects themselves are an indication that your body’s immune system is working. Here’s more about the potential side effects of the COVID-19 vaccines

“Most people experience mild symptoms, particularly arm pain after the first dose,” says Bernard Kaminetsky, MD, medical director, MDVIP. “However, flu-like symptoms are common after the second dose.”  

Do I Have to Keep Wearing a Mask After I’ve Had My Coronavirus Vaccine? 

Even after being fully vaccinated, you’re not off the hook from wearing a mask. Why? The vaccine doesn’t provide 100 percent protection. It might sound odd, given that Moderna and Pfizer vaccines up to 95 percent effective after both doses. But even if your immune system responded ideally to the vaccine – and keep in mind everyone’s immune system is different – there’s still a five percent window. 

And the vaccine doesn’t act like a shield to keep the virus out of your body. It teaches your body to fight the virus and keep you from becoming sick. But you can still become infected and spread the virus to others. You may be asymptomatic -- think Typhoid Mary. But you can still spread infection.  

There are also other variants of the virus. While researchers think the vaccines are effective against them, there are some variants they are less effective against. This factor makes wearing masks ideal. Read more about the variants here

And of course, there’s the million-dollar question: How long does immunity last after vaccination? The answer: We don’t know yet.  

Long-term immunity involves several parts of the immune system, including antibodies, T cells and B cells. We know that antibodies – proteins that fight the virus – remain fairly stable in most people six months after the virus, even if they decline somewhat. T and B cells, which identify and fight viruses, actually increase over time – people had more of them six months after infection than one month afterwards. Researchers think this is a good sign that immunity lasts, but they don’t know how long. We may need boosters for COVID vaccines eventually, which means wearing masks is still one of the safest ways to keep from spreading the virus. 

There is hope that all these precautions will be less necessary in the near future as more people get vaccinated. Study results released last week (not yet published or peer-reviewed) suggest that people who’ve been vaccinated carry lower viral loads of the coronavirus than people who are not. This means they should be less communicable and less likely to spread the virus. When coupled with other data showing that effectiveness of the vaccines, the risk of becoming ill with COVID-19 or spreading the virus may be greatly reduced after vaccination. The risk isn’t zero, but it is low, hence the CDC’s guidelines. For now, we recommend following the CDC’s precaution guidelines.

Social Distancing 

Once you get the vaccine, your risk of becoming very ill from the coronavirus drops. But it doesn’t drop to zero. You should still wear masks, which means you should still practice social distancing. They go hand in hand. Activities that require taking off your mask, like eating at a restaurant, should still be considered higher risk than activities like shopping for groceries, even after your vaccination.  


Many of us have been grounded since mid-March 2020 and are eager to resume air travel for vacations and business. Scientists believe the Pfizer vaccine reaches its full effectiveness seven days after the second dose; Moderna takes about 14 days.   

“I don’t advise anyone to travel during the pandemic. However, if you must travel for an emergency, I strongly recommend postponing travel until you’ve had both doses,” Kaminetsky says. “Even if you’ve had both doses, you should wait at least a couple of weeks for the vaccine to kick in before getting on a plane.” 

If you fly out of the country, a recent COVID-19 test is required before returning to the U.S. You’ll have to show test results (which shouldn’t be more than three days old) before boarding. This mandate applies to both vaccinated and unvaccinated travelers. And quarantining is still necessary because scientists think you may be able to spread COVID-19 even if you’ve been vaccinated. Proof of vaccination may eventually be required by some airlines, so if you are vaccinated, make sure you keep your vaccination card in a safe place.  


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About the Author
Janet Tiberian Author
Janet Tiberian, MA, MPH, CHES

Janet Tiberian is MDVIP's health educator. She has more than 25 years experience in chronic disease prevention and therapeutic exercise.

View All Posts By Janet Tiberian, MA, MPH, CHES
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