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Pfizer, Moderna, Johnson & Johnson: Everything to know about the 3 COVID-19 vaccines

Moderna, Pfizer-BioNTech and Johnson & Johnson have each produced a safe and effective vaccine for COVID-19. Here's what you need to know about the options.
/ Source: TODAY

As COVID-19 cases are rising, experts stress that all three COVID-19 vaccines are widely available in the U.S. and are safe and effective against serious illness. While the best vaccine for you is whatever option is most readily available in your area, there are important distinctions between the Pfizer-BioNTech, Moderna and Johnson & Johnson vaccines.

To date, over 160 million Americans have been fully vaccinated, according to the Centers for Disease Control and Prevention. As vaccinations continue, the CDC is closely monitoring any health issues that could be related to the vaccines. There have been more than 300 cases of myocarditis or pericarditis, inflammation of the heart or tissue surrounding the organ, in young people following COVID-19 vaccinations, the CDC reported in June. NBC News reported that most cases were not serious. This spring, the CDC reported rare cases of blood clots among people who have received the Johnson & Johnson COVID-19 vaccine. The organization stresses that women younger than 50 years old should especially be aware of the risk of blood clots with low platelets after receiving a Johnson & Johnson vaccination.

Here is everything else you need to know about the available COVID-19 vaccines.


The Pfizer-BioNTech coronavirus vaccine (an mRNA vaccine) was the first one to be granted authorization in the United States; the U.S. Food and Drug Administration gave the vaccine an emergency use authorization last December. Shots started going into arms in the U.S. on Dec. 14, 2020.

The Pfizer vaccine requires two doses, three weeks apart. People are considered fully vaccinated two weeks after receiving their second dose of the vaccine. Approval was expanded to include anyone over the age of 12 in the spring. Pfizer said in a statement to NBC News it expects data on its clinical trials in children between the ages of 5 and 11 in September.

While the vaccine has not been officially approved for use during pregnancy, pregnant people are encouraged to discuss their options with their doctors. Pfizer launched its clinical trials of its COVID-19 vaccine in pregnant women in February. A recent study of pregnant people who received either the Pfizer or Moderna vaccines found that pregnant or breastfeeding mothers showed a robust immune response to the vaccines, and antibodies were present in their umbilical cord blood and breast milk.

Recent research has found that the vaccine was 97% effective at preventing serious illness from COVID-19 for at least six months, NBC News reported. Though the effectiveness against symptomatic COVID-19 began to wane slightly two months post-vaccination.

People who receive the Pfizer vaccine may experience mild, flu-like side effects, with the possibility for more severe side effects following the second dose. According to the Centers for Disease Control and Prevention, side effects usually start within a day or two of receiving the vaccine. The most commonly reported side effects include localized reactions like swelling or soreness at the injection site, fatigue, chills, fever or a headache. The CDC recommends people who are not feeling better after 24 hours contact their doctor. There have been some reports of allergic reactions.


Moderna's coronavirus vaccine (also an mRNA vaccine) was granted an EUA by the FDA on Dec. 18, 2020, and people first started receiving doses of the vaccine soon after.

The Moderna vaccine requires two doses, four weeks apart. People who receive the Moderna vaccine are considered fully vaccinated two weeks after their second dose. Real-world studies show that the vaccine is 90% effective in adults.

The Moderna vaccine has been approved for adults over the age of 18. The company filed for an EUA for the vaccine to be used in kids ages 12 to 17 in early June. Like the Pfizer-BioNTech vaccine, the Moderna vaccine has not been officially approved in pregnant people, but moms-to-be can consult with their doctors to make a decision about receiving vaccinations. A recent study found that new and expectant mothers who received the Moderna or Pfizer vaccines have also passed on antibodies to their children. Moderna has also begun trials in younger children.

The Moderna vaccine has similar side effects as those reported in other coronavirus vaccines. The Moderna vaccine may be more likely to result in mild, temporary skin reactions, such as redness around injection site about a week after receiving a dose of the vaccine.

Johnson & Johnson

The Johnson & Johnson vaccine, a viral vector vaccine, was granted an EUA on Feb. 27. On April 13, the FDA and CDC recommended a "pause" in the use of the vaccine "out of an abundance of caution." The agencies were reviewing data involving several cases of a rare and severe type of blood clot mostly occurring in women after receiving the shot in the days prior. The pause was lifted on April 23.

The vaccine requires just one dose. People who receive the Johnson & Johnson vaccine are considered fully vaccinated two weeks after their vaccination.

The Johnson & Johnson vaccine has a lower efficacy rate than the other two vaccines, about 72% in the United States. However, the single-dose vaccine is extremely effective at preventing severe COVID-19, and no clinical trial participants who received the vaccine were hospitalized or died of the coronavirus.

The vaccine is authorized in adults aged 18 and up. Like the other two vaccines, it was not tested in pregnant women, but people who are expecting are encouraged to talk with their doctors to make a decision about vaccination. In its application for an EUA, the company said that they plan to test their vaccine in pregnant women and younger children.

The Johnson & Johnson vaccine was tested in Latin America and South Africa, where two alarming variants were prevalent. Experts believe this may account for its lower reported efficacy rate. In Latin America, the Johnson & Johnson vaccine effectiveness was 66%, and in South Africa, the effectiveness fell to 64%. However, even vaccinated people who contracted the variant strains of the virus were not hospitalized.

Clinical trial data showed that the most common side effects were fever, fatigue, headache, muscle aches and pain at injection site. Side effects were common within seven days of getting vaccinated; side effects were more common in people ages 18-59 than in people 60 years and older, according to the CDC.

Experts have stressed over and over again that all three vaccines are safe and effective, and as soon as you're eligible, get whichever vaccine is offered to you first.

This story was updated on July 29, 2021.