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Last updated February 8, 2021. 4 minute read

Can you still get COVID-19 even with the vaccine?

You can’t get COVID-19 from the vaccine, but you may develop certain symptoms, which are signs that your immune system is responding to the vaccine.

Dr Chimene Richa Md Written by Dr. Chimene Richa, MD
Reviewed by Dr. Steve Silvestro, MD

Coronavirus disease 2019 (COVID-19) is currently the leading cause of death in Americans over 35 years of age (Woolf, 2021). The most common symptoms of COVID-19 include fevers or chills, cough, fatigue, and a new loss of taste or smell (CDC, 2020). 

However, data suggests that approximately one in six people infected with the virus do not develop any symptoms—in other words, they are asymptomatic. Others may develop severe symptoms like trouble breathing and may need to be admitted to the hospital. Asymptomatic people can still pass the virus on to others, which is why mask-wearing and social distancing measures are necessary (Byambasuren, 2020). Here’s more on the vaccine and if you can get COVID-19 even after getting it.

Vitals

  • Clinical trials show that the Moderna and Pfizer-BioNTech COVID-19 vaccines are 94.5% and 95% effective at protecting you against COVID-19, respectively. 
  • You can’t get COVID-19 from the vaccine, but you may develop symptoms—like arm soreness, fatigue, headaches, and muscle aches—which are signs that your immune system is responding to the vaccine..
  • Some people who get the virus, but never develop symptoms of COVID-19, may still be able to pass the infection on to others, even after getting the vaccine.

Can you still get COVID-19 even after getting the vaccine?

The short answer is that scientists are not sure. The clinical trials on these vaccines showed that they effectively prevented COVID-19 disease—94.5% effectiveness for the Moderna vaccine and a 95% effectiveness for the Pfizer-BioNTech version (FDA, 2020a; FDA, 2020b). The clinical trials measured effectiveness by looking at how many people developed the COVID-19 disease after receiving the vaccine. 

COVID-19 disease refers to people who developed symptoms of COVID-19 and not people who were just infected with the virus. The virus that causes COVID-19, SARS-CoV-2, sometimes infects people without causing any symptoms (asymptomatic).  Asymptomatic people in the clinical trials were not counted among those who reported having COVID-19 disease (e.g., trouble breathing, fevers, etc.). It is possible that you could be infected with the COVID-19 virus, but not realize it since you don’t have any symptoms, and pass it on to others unknowingly. So it is important to keep wearing your mask and practice social distancing, even if you have received the vaccine. 

Both vaccines are very effective in preventing COVID-19 disease—in other words, preventing you from getting sick with COVID-19. However, scientists do not know if the vaccines can protect you from getting infected with the SARS-CoV-2 virus and remaining asymptomatic, while still potentially passing it along to others.

Another thing to consider is time. You need to wait either 21 or 28 days, depending on which vaccine you receive, between the two doses of the vaccine to get the full effect.  Vaccines do not work instantaneously—it takes time for your immune system to make antibodies and build up protection against the COVID-19 virus. Therefore, you need one or two weeks after the 2nd dose of the vaccine to be maximally protected (FDA, 2020a; FDA, 2020b). 

It is possible to get sick with COVID-19 after getting the vaccine if you are exposed to the SARS-CoV-2 virus right after receiving your first dose. Your body hasn’t had a chance to mount a response to the virus, and you are just as vulnerable as someone who didn’t get the shot. However, if given time, and the second dose of the vaccine, your chances of developing COVID-19 decrease significantly. 

How does the COVID-19  vaccine work?

Since the U.S. Food and Drug Administration (FDA) approved Emergency Use Authorization (EUA) for the Moderna and Pfizer/BioNTech mRNA vaccines, millions of people in the U.S. and worldwide have received the vaccines. The COVID-19 vaccines carry viral genetic blueprints for the spike proteins that line the virus’s outer capsule and help it enter your cells. After you get the vaccine, your protein-making factories take the blueprints and make replica viral spike proteins, which trigger your immune system to produce antibodies against future infection. If you are exposed to the COVID-19 virus in the future, your body is armed and ready to attack the virus before it can make you sick.

Can you get COVID-19 from the vaccine?

You cannot get COVID-19 from the vaccine—just like you can’t put together a 300-piece puzzle with only one piece. The COVID-19 mRNA vaccines only contain the genetic blueprints that allow your body’s protein factories to make only one piece of the virus—the viral spike proteins. That’s it. There are not enough parts of the virus included in the vaccine for you to get sick with COVID-19. 

Some people experience side effects after receiving the vaccine, like arm soreness (in the side that got the vaccine), fatigue, headaches, and muscle aches. These are not symptoms of being ill with COVID-19. They are signs that your immune system is responding to the viral proteins and making.