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Last updated September 10, 2021. 3 minute read

Can you still get COVID-19 even once you’ve been vaccinated?

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 Chimene Richa, MD
Reviewed by Steve Silvestro, MD

As cases of COVID-19 continue to fluctuate throughout the country, you may be wondering whether vaccination really prevents illness. Luckily, extensive studies performed around the world have compared vaccinated and unvaccinated individuals and shown that the COVID-19 vaccines are very effective when it comes to preventing serious disease from coronavirus. That said, no vaccine is 100% effective and even if you are fully vaccinated, you can still catch the coronavirus. The vaccine both reduces your chance of catching the virus and reduces the chance of serious infection and death if you do catch the virus.

Vitals

  • The Moderna vaccine and the Pfizer BioNTech vaccine have been proven to be 94.5% and 95% effective at preventing infection with coronavirus in people age 16 and up. No vaccine is 100% effective and you can still catch COVID-19 even if you’re fully vaccinated, but you are less likely to develop severe disease or require hospitalization. Since most cases of COVID-19 are actually asymptomatic, you 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 yes. The clinical trials on these vaccines showed that they effectively prevented COVID-19 disease—94.5% effectiveness for the Moderna vaccine and 95% effectiveness for the Pfizer-BioNTech vaccine (Oliver, 2020). The clinical trials measured effectiveness by looking at how many people developed the COVID-19 disease after receiving the vaccine and compared them to people who caught COVID-19 without being vaccinated. 

While these rates are impressive, it’s still possible that you could be infected with the coronavirus virus and pass it on to others unknowingly, especially if you never develop symptoms. While mask mandates seem to be going in and out of style, and with the rise of different variants that may require additional vaccines, it’s important to take precautions and avoid exposing at-risk people to the coronavirus, even if you have received the vaccine. 

How does the COVID-19  vaccine work?

Millions of people in the U.S. and worldwide have received vaccines to prevent COVID-19. The mRNA vaccines currently available in the United States carry genetic blueprints for the spike proteins that line the virus’s outer capsule. After you get the vaccine, your cells take the blueprints and make replicas 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 cells 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 where they got the injection, 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. 

References

  1. Byambasuren, O., Cardona, M., Bell, K., Clark, J., McLaws, M., & Glasziou, P. (2020). Estimating the extent of asymptomatic COVID-19 and its potential for community transmission: Systematic review and meta-analysis. Official Journal Of The Association Of Medical Microbiology And Infectious Disease Canada, 5(4), 223-234. doi: 10.3138/jammi-2020-0030. https://jammi.utpjournals.press/doi/10.3138/jammi-2020-0030
  2. Centers for Disease Control and Prevention (CDC). (2020, December). Symptoms of Coronavirus. Retrieved on February 5, 2021 from https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html

    Oliver S, Gargano J, Marin M, et al. The Advisory Committee on Immunization Practices’ Interim Recommendation for Use of Pfizer-BioNTech COVID-19 Vaccine — United States, December 2020. MMWR Morb Mortal Wkly Rep 2020;69:1922-1924. DOI: 10.15585. Retrieved Aug. 23, 2021 from https://www.cdc.gov/mmwr/volumes/69/wr/mm6950e2.htm?s_cid=mm6950e2_w
  3. U.S. Food and Drug Administration (FDA) (2020a, December) Vaccines and Related Biological Products Advisory Committee Meeting – FDA Briefing Document: Moderna COVID-19 Vaccine. Retrieved on February 5, 2021 from https://www.fda.gov/media/144434/download
  4. U.S. Food and Drug Administration (FDA) (2020b, December) Vaccines and Related Biological Products Advisory Committee Meeting – FDA Briefing Document: Pfizer-BioNTech COVID-19 Vaccine. Retrieved on February 5, 2021 from https://www.fda.gov/media/144245/download
  5. Woolf SH, Chapman DA, Lee JH. (2021). COVID-19 as the Leading Cause of Death in the United States. JAMA. 325(2):123–124. doi:10.1001/jama.2020.24865 https://jamanetwork.com/journals/jama/fullarticle/2774465