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Comparing the Pfizer and Moderna COVID-19 Vaccines

Both are revolutionary mRNA vaccines that are highly effective—94 to 95%—against COVID-19. But there are a few differences.

Safe, effective COVID-19 vaccines are here

Across the globe, pharma companies are racing to roll out safe, effective vaccines to combat COVID-19 disease. According to the World Health Organization (WHO), over 50 vaccines are now in trials, with seven receiving regulatory approval in various countries.

Here in the U.S., the Food and Drug Administration (FDA) has approved the use of two mRNA COVID-19 vaccines: The Pfizer-BioNTech vaccine, and the Moderna vaccine.

Comirnaty by Pfizer is the first vaccine to receive full authorization from the FDA for individuals ages 16 and older. It has also been granted emergency use authorization (EUA) for children 5-15. The Moderna vaccine currently has EUA for use in individuals 18 and older.

Despite their different levels of authorization, the safety of both these products was, and is, a top priority. The FDA is required to make decisions that are guided by science and data. The makers of these vaccines followed every necessary step to meet the FDA’s emergency authorization process. Both vaccines have been through a series of reviews and were rigorously tested for safety, effectiveness and quality.

Advances in science enabled the rapid development of these vaccines, which wasn’t possible just a few years ago. The federal government’s unprecedented investments also encouraged companies to start producing the COVID-19 vaccine sooner than is typical.

Did you know?


Because the mRNA used in both vaccines is fragile, cold storage is required to ensure they are stable. Pfizer’s vaccine requires ultra-cold shipment and storage at -94⁰ F, compared to Moderna’s at -4⁰ F. This makes Moderna’s far less challenging to use than Pfizer’s, which requires special freezers. While both vaccines are shipped and stored frozen, they are thawed before injection.

Two different vaccines—one common goal

Although developed by different manufacturers, the two vaccines are very similar. Both are mRNA vaccines that “teach” the body to make the spike protein found on the virus. This protein triggers your immune system, which creates antibodies specific to COVID-19. These antibodies protect the body and help fight future infection.

The Pfizer/BioNTech vaccine showed 95% protection during a clinical trial of 44,000 participants. The Moderna vaccine showed 94% protection in a clinical trial of 30,000. In comparison, the effectiveness of the common flu vaccine varies each year between 40% and 60%.

As reported in both the Pfizer and Moderna trials, the level of effectiveness of each manufacturer’s vaccine was consistent across age, gender, race and ethnicity. Each trial included a range of white, Hispanic/Latinx, Black, Asian and multiracial participants.

Comparing the VaccinesPfizer-BioNTech mRNA VaccineModerna mRNA Vaccine

Doses and Timing
Two doses, three weeks apart Two-dose vaccine, four weeks apart

Who can receive it
Recommended for people ages 5 years or older Recommended for people ages 18 years or older

Storage
Requires ultra-cold storage (-94⁰ F) Requires standard cold storage (-4⁰ F)

Available doses
3 billion doses to the world in 2021 500 million to 1 billion doses to the world in 2021

Effectiveness
Large-scale trial (44,000 participants) showed 95% protection from disease Large-scale trial (30,000 participants) showed 94% protection from disease

Giving COVID the one-two punch

Both vaccines are given in a series of two injections. The first is a priming dose that prepares the immune system. The second is a booster shot that strengthens the body’s immune response.

Pfizer’s vaccine requires the two doses to be given 21 days apart, while Moderna’s doses are delivered 28 days apart.

Can children get vaccinated?

Pfizer’s vaccine is currently recommended for individuals 5 years or older. And Moderna’s for those 18 or older.

If the trials show the vaccines are safe for younger children, future tests could eventually consist of toddlers and infants.

By law, vaccine companies must test all their products on children, including the COVID-19 vaccine. But testing takes time, making it unlikely that children will be vaccinated before the next school year starts.