Moderna COVID-19 Vaccine Overview and Safety
CDC has received increased reports of myocarditis and pericarditis in adolescents and young adults after COVID-19 vaccination. The known and potential benefits of COVID-19 vaccination outweigh the known and potential risks, including the possible risk of myocarditis or pericarditis. We continue to recommend COVID-19 vaccination for anyone 12 years of age and older.
Manufacturer: ModernaTX, Inc.
Type of Vaccine: mRNA
Number of Shots: 2 shots, 28 days apart
How Given: Shot in the muscle of the upper arm
Does NOT Contain: Eggs, preservatives, latex, metals
Full List of Ingredients
- The Moderna vaccine is recommended for people aged 18 years and older.
- Learn more about how CDC is making COVID-19 vaccine recommendations.
- If you have had a severe allergic reaction (anaphylaxis) or an immediate allergic reaction, even if it was not severe, to any ingredient in an mRNA COVID-19 vaccine (such as polyethylene glycol), you should not get an mRNA COVID-19 vaccine.
- If you had a severe or immediate allergic reaction after getting the first dose of an mRNA COVID-19 vaccine, you should not get a second dose of either of the mRNA COVID-19 vaccines (Moderna or Pfizer-BioNTech).
- A severe allergic reaction is one that needs to be treated with epinephrine or EpiPen or with medical care. Learn about common side effects of COVID-19 vaccines and when to call a doctor.
- An immediate allergic reaction means a reaction within 4 hours of getting the shot, including symptoms such as hives, swelling, or wheezing (respiratory distress).
If you aren’t able to get an mRNA COVID-19 vaccine, you may still be able to get a different type of COVID-19 vaccine. Get more information for people with allergies.
Possible Side Effects
In the arm where you got the shot:
Throughout the rest of your body:
- Muscle pain
These side effects happen within a day or two of getting the vaccine. They are normal signs that your body is building protection and should go away within a few days.
Learn more about possible side effects after getting a COVID-19 vaccine.
COVID-19 vaccines are not interchangeable. If you received a Pfizer-BioNTech or Moderna COVID-19 vaccine, you should get the same product for your second shot.
Safety Data Summary
- In clinical trials, reactogenicity symptoms (side effects that happen within 7 days of getting vaccinated) were common but were mostly mild to moderate. Few people had reactions that affected their ability to do daily activities.
- Side effects throughout the body (such as fever, chills, tiredness, and headache) were more common after the second dose of the vaccine.
- CDC will continue to provide updates as we learn more about the safety of the Moderna vaccine in real-world conditions.
Learn more about vaccine safety monitoring after a vaccine is authorized or approved for use.
How Well the Vaccine Works
- Based on evidence from clinical trials, in people aged 18 years and older, the Moderna vaccine was 94.1% effective at preventing laboratory-confirmed COVID-19 infection in people who received two doses and had no evidence of being previously infected.
- The vaccine was also highly effective in clinical trials at preventing COVID-19 among people of diverse age, sex, race, and ethnicity categories and among people with underlying medical conditions.
- CDC will continue to provide updates as we learn more about how well the Moderna vaccine works in real-world conditions.
Clinical trials for the Moderna vaccine included people from the following racial, ethnic, age, and sex categories:
- 79% White
- 10% African American
- 5% Asian
- <3% other races/ethnicities
- <1% American Indian or Alaska Native
- <1% Native Hawaiian or Other Pacific Islander
- 79% not Hispanic or Latino
- 20% Hispanic or Latino
- 1% unknown
- 53% male
- 47% female
- 75% 18 through 64 years
- 25% 65 years and older
Twenty-two (22%) of people who participated in the clinical trials had at least one condition that put them at risk of severe illness from COVID-19. The most frequent underlying medical conditions among participants were lung disease, heart disease, obesity, diabetes, liver disease, or HIV infection. Four percent (4%) of participants had two or more high-risk conditions.
Most people who participated in the trials (82%) were considered to have an occupational risk of exposure, with 25% of them being healthcare workers.