Everything You Need to Know About the Moderna Vaccine

doctor extracting coronavirus vaccine

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Key Takeaways

  • The Moderna COVID-19 vaccine has received full approval from the U.S. Food and Drug Administration (FDA) for people 18 years and older.
  • Shots of this vaccine are now available for people ages 6 months and older.
  • The FDA has authorized an updated booster dose of either the Pfizer-BioNTech or Moderna vaccine for everyone age 6 months and older. Children ages 6 months to 5 years old who completed the Moderna primary series at least two months ago should get a Moderna booster.
  • The Moderna vaccine does not appear to have any serious risks for pregnant people and is recommended for use in pregnancy by top U.S. health organizations.

On January 31, 2022, the FDA granted full approval for use of the Moderna COVID-19 vaccine in people ages 18 and older. The newly approved vaccine is also known as Spikevax.

Moderna's vaccine followed Pfizer-BioNTech's as the second vaccine available in the U.S. to fight the coronavirus pandemic. The Moderna vaccine is recommended by the Centers for Disease Control and Prevention (CDC) to protect against COVID-19.

It's widely available, and more than 261 million doses of Moderna's original vaccine and bivalent booster have been administered in the U.S. to date. Here’s everything your family needs to know about the Moderna vaccine. 

How Does It Compare to the Pfizer Vaccine?

Both the Pfizer and Moderna vaccines are formulated with mRNA technology. Unlike other types of vaccines that trigger an immune response by injecting a weakened or inactivated germ into the body, an mRNA vaccine teaches our cells how to make their own immune response.

It does this by encoding part of the spike protein found on the surface of the virus that causes COVID-19. Both vaccines are administered in two doses—three to eight weeks apart for the Pfizer vaccine and four to eight apart for the Moderna vaccine.

The FDA has authorized a bivalent booster shot from Pfizer or Moderna for all people ages 6 months and older, to be given at least two months after a previous shot (or as part of their Pfizer primary series, if it hasn't been completed yet). This updated booster protects against the Omicron variant, which is predominant in the U.S., as well as the original strain.

If you qualify for a COVID-19 booster dose, you can safely receive a different brand of FDA-authorized vaccine than the one you received for your earlier shots, according to the CDC. That means you can receive a Moderna booster even if you had the Pfizer or J&J vaccine previously, or you can get a Pfizer booster even if you started out with the Moderna or J&J vaccine. The Moderna and Pfizer booster shots are recommended over the J&J shot. Be sure to talk to your doctor about whether "mixing and matching" vaccines may be a good idea for you.

Early clinical trials showed that both mRNA vaccines are highly effective against COVID-19, with Pfizer offering 95% protection and Moderna offering 94.1% protection. Research showed that Moderna's vaccine remains 92% effective after 120 days, while the Pfizer vaccine's efficacy drops to 77% after that period.

Neither vaccine was quite as effective against the Delta variant predominating in late 2021, or against the Omicron variant that eventually replaced the Delta variant in prominence. But the bivalent booster is effective against both the original strain and the Omicron variant.

What About My Children?

The Moderna vaccine is now available for everyone ages 6 months and over. (The Pfizer vaccine can also be given to people ages 6 months and over).

The COVID-19 vaccine dosages in children have been determined through extensive clinical trials, with young children getting smaller dosages than adults. "Each vaccine can vary," says Danelle Fisher, MD, pediatrician and vice chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, California.

Dr. Fisher points to the flu vaccine as one example—children under age 8 who are getting the vaccine for the first time need to get two doses, four weeks apart. Thereafter, they get one dose per year, just like adults do.

Danelle Fisher, MD

Get your children a flu vaccine if they haven’t gotten one yet. No one wants to have the flu in addition to COVID-19.

— Danelle Fisher, MD

Can I Get the Moderna Vaccine If I’m Pregnant or Breastfeeding?

The CDC and the American College of Obstetricians and Gynecologists (ACOG) recommend that people who are pregnant get vaccinated against COVID-19.

Pregnant people were not included in early clinical trials of the Moderna vaccine or any other COVID-19 vaccine. Moderna is now performing clinical trials to look at the vaccine's safety and effectiveness in pregnant people, specifically.

A preliminary study published in the New England Journal of Medicine did find that the Moderna vaccine does not pose a serious risk for pregnant people. The findings were based on the CDC's V-safe smartphone-based surveillance system and the CDC's Vaccine Adverse Event Reporting System (VAERS), which included data from 35,691 pregnant people who had received an mRNA vaccine.

In a practice advisory, ACOG recommends that people who are breastfeeding also receive a COVID-19 vaccine. Recent research suggests that breastfeeding people who have received an mRNA vaccine like Moderna's have antibodies in their breast milk, which may provide added COVID-19 protection for the baby.

What to Expect When You Get the Vaccine 

In an FDA briefing document regarding Moderna's COVID-19 vaccine, the following symptoms are listed as potential side effects:

  • Chills
  • Fever
  • Headache
  • Injection site pain, swelling, or redness
  • Joint pain
  • Muscle pain
  • Nausea and/or vomiting
  • Tiredness

What This Means For You

Everyone ages 6 months and older is eligible for the Moderna vaccine, which research has shown to provide safe and effective protection against COVID-19, particularly against severe illness and death. The vaccine is recommended for pregnant and breastfeeding people, and updated bivalent booster doses are available for people ages 6 months and older.

It's crucial to continue to follow other COVID-19 safety measures, like wearing a face mask in indoor public spaces and keeping social distance in crowded settings. When you do socialize, gather outside when possible.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

18 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  10. Centers for Disease Control and Prevention. CDC expands eligibility for COVID-19 booster shots.

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  14. Link-Gelles R, Ciesla AA, Fleming-Dutra KE, et al. Effectiveness of bivalent mRNA vaccines in preventing symptomatic SARS-CoV-2 infection — increasing community access to testing program, United States, September–November 2022MMWR Morb Mortal Wkly Rep. 2022;71:1526–1530. doi:10.15585/mmwr.mm7148e1

  15. Centers for Disease Control and Prevention. Flu & young children.

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By Claire Gillespie
Claire Gillespie is a freelance writer specializing in mental health. She’s written for The Washington Post, Vice, Health, Women’s Health, SELF, The Huffington Post, and many more. Claire is passionate about raising awareness for mental health issues and helping people experiencing them not feel so alone.