There are three COVID-19 vaccines approved for use in the U.S. The Pfizer, Moderna, and Johnson & Johnson vaccines are all highly effective in protecting you from the virus that causes COVID-19.
The CDC says there’s a preference for the mRNA (Pfizer and Moderna) COVID-19 vaccines over the Johnson & Johnson vaccine. This is based on data from the Advisory Committee on Immunization Practices (ACIP). It discussed vaccine safety, vaccine effectiveness, rare negative side effects, and U.S. vaccine supply.
It’s best to get a booster shot from either Pfizer or Moderna, but any booster is better than none. If you only have access to the Johnson & Johnson booster, you should still get it.
The Pfizer vaccine received full FDA approval on Aug. 23 and is no longer under emergency use authorization (EUA). It will now be marketed under the name Comirnaty.
Two other vaccines, from Novavax from AstraZeneca, are not available in the U.S.
Vaccines continue to lower your risk for severe disease, hospitalization, and death, even against the widespread Delta variant of COVID-19.
But each is slightly different. Compare them below. If you’re still not sure which vaccine is best for you, talk to your doctor.
Vaccine developer: | Pfizer | Moderna | AstraZeneca | Johnson & Johnson | Novavax |
How it works | Messenger RNA | Messenger RNA | Inactivated cold virus | Modified cold virus | Stabilized form of the coronavirus spike protein |
When approved/expected approval | Given full FDA approval Aug. 23, 2021 | Dec. 18, 2021 | Not yet available. Phase III clinical trials in progress as of Feb. 27 | Feb. 27 | Not yet available. Results from phase III clinical trials published June 14. |
What percentage of people did it protect from getting infected in clinical studies? | 95% | 94.1% | 70% | 66.1% globally; 72% in the U.S.; 86% effective against severe disease | 89.7% |
Who is it recommended for? | People 5 years and older | People 18 years and older | Not yet available | People 18 years and older | Not yet available |
How many shots do you need? | Two doses, 3 weeks apart | Two doses, 4 weeks apart | Two doses, a month apart | One dose | Two doses, 21 days apart |
When might you become eligible for a booster shot? | At least 5 months after your primary COVID-19 vaccination series (for people 16 years and older). Teens between 12 and 17 may only get the Pfizer booster shot. | At least 6 months after your primary COVID-19 vaccination (for people 18 years and older) | To be determined | At least 2 months after your primary J&J COVID-19 vaccination (for people 18 years and older) | |
What are the side effects? | Fatigue, headache, chills, muscle pain, especially after the second dose | Fever, muscle aches, headaches lasting a few days. Effects worse after second dose. | Pain where you get the shot, fever, muscle aches, headache | Pain where you get the shot, headache, fatigue, muscle pain | Pain and tenderness where you get the shot, fatigue, headache, muscle pain |
Any warnings? | The FDA issued a warning in June about heart inflammation. Since April 2021, there have been more than a thousand reports of myocarditis and pericarditis. These cases are still relatively low. | The FDA issued a warning in June about heart inflammation. Since April 2021, there have been more than a thousand reports of myocarditis and pericarditis. These cases are still relatively low. |
| In July, the FDA issued a warning about an increased risk for developing Guillain-Barre syndrome. | |
What about pregnant women and nursing moms? | Pregnant women or nursing moms who want the COVID-19 vaccine should get one, experts say. The vaccine has not yet been studied in pregnant women. Read guidelines here. | There's limited data. Studies in rats that were immunized before and during pregnancy found no safety concerns. The CDC says pregnant women may choose to receive the vaccine. | Not yet available | Discuss your options with your health care provider. | Not yet available |
Is there anyone who shouldn’t get the vaccine? | People with a history of serious allergic reactions, anyone with a history of allergic reactions to vaccine ingredients, including polyethylene glycol, and anyone with a history of allergic reactions to polysorbate | People with a history of serious allergic reactions, anyone with a history of allergic reactions to vaccine ingredients, including polyethylene glycol, and anyone with a history of allergic reactions to polysorbate | Not yet available | Anyone who’s had an allergic reaction to an ingredient in the vaccine, like polysorbate | Not yet available |
Any significant side effects? | Extremely rare cases of anaphylaxis in people who received the vaccine. Extremely rare cases of Bell's palsy, a type of temporary facial paralysis, reported in people who received the vaccine. | Extremely rare cases of anaphylaxis in people who received the vaccine. Extremely rare cases of Bell's palsy, a type of temporary facial paralysis, reported in people who received the vaccine. | Four total serious side effects, including two cases of transverse myelitis | There is a possible, rare relationship between this vaccine and blood clots with low platelets. | Not yet available |
What about people with lowered immune function? | OK for people whose immune function is lowered by HIV or immunosuppressing drugs if they have no other reasons to avoid it. There is limited safety data in this group. Discuss the benefits and risks with your doctor. | OK for people whose immune function is lowered by HIV or immunosuppressing drugs if they have no other reasons to avoid it. There is limited safety data in this group. Discuss the benefits and risks with your doctor. | Not yet available | Not yet available | Not yet available |
What about people with autoimmune diseases? | No data is available on the safety or effectiveness of mRNA vaccines in people with autoimmune disease. People with autoimmune conditions may still get the shots if they have no other reasons to avoid vaccination. | No data is available on the safety or effectiveness of mRNA vaccines in people with autoimmune disease. People with autoimmune conditions may still get the shots if they have no other reasons to avoid vaccination. | Not yet available | Not yet available | Not yet available |
Is the vaccine safe for people with a history of Guillain-Barre syndrome (GBS)? | To date, no cases of GBS have been seen in people vaccinated for COVID-19. The CDC says a history of GBS is not a reason to avoid vaccination. | To date, no cases of GBS have been seen in people vaccinated for COVID-19. The CDC says a history of GBS is not a reason to avoid vaccination. | Not yet available | There’s a possible, but rare risk in developing Guillain-Barre syndrome after this vaccine. | Not yet available |