Understanding the COVID-19 Vaccine, part 4: Head to Head - Comparing the Pfizer and Moderna Vaccines

by Meris Shuwarger January 25, 2021 Updated: January 18, 2023 3 min read 2 Comments

Do you have questions about the recently released COVID-19 vaccines? Over a series of posts, we have been covering this new development in depth! Today we take a look at the differences between the Pfizer and Moderna COVID-19 vaccines.

Based on the way that the vaccines are being rolled out in each state, a person may not have the option to choose which manufacturer’s vaccine they will take. In most cases there is only one option available. However it is still interesting to examine the differences between the Pfizer and Moderna vaccines, as these are currently on the market and being widely distributed.

Similarities between the Pfizer and Moderna Vaccines

  1. Both vaccines use the mRNA technology, which we examined in our previous blog post on the topic.
  2. They both require a second “booster” shot after the initial vaccine is administered.
  3. The efficacy of each is exceptional and nearly identical. Pfizer showed a 95% efficacy rate, while Moderna came in slightly lower at 94.1%.
  4. Reactogenicity (that is, the expected immune response from vaccination) is similar in both, leading to expected side effects such as fever, fatigue, and muscle soreness. Remember, these are good and normal side effects! Check out the first post in the vaccine series if you need a refresher.
  5. It is unknown how long each vaccine will provide immunity. Each manufacturer is still conducting research to determine this by measuring antibody decay rates. Recent data suggests the Moderna vaccine may provide immunity for at least a year!

Differences between the Pfizer and Moderna Vaccines

  1. The dosage is different. Pfizer’s dosage is only 30 micrograms, while Moderna carries a 100 microgram dose.
  2. Pfizer is approved for use in patients with a minimum age of 16, while Moderna is only cleared for use in those over the age of 18.
  3. Although they both require a booster shot, Pfizer’s is to be administered after 21 days. Moderna’s is slightly longer, requiring 28 days between doses. This also means that the time it takes to reach optimal efficacy is about a week longer with Moderna.
  4. Most notably for those who stock the vaccine, the storage profiles differ drastically. Pfizer’s requires a shipping and storage temperature of -94*F, and it must be used within five days of thawing. Moderna, on the other hand, is shipped at a much higher temperature of -4*F, and it is able to be kept at a normal refrigerated temperature for 30 full days.
  5. Each comes in a multi-dose vial, with Pfizer’s containing just 5 doses and Moderna’s containing 10.
  6. Another notable difference for those who plan to order and administer the vaccine is the minimum purchase amount. Pfizer requires a minimum of 975 doses to be ordered. While this makes sense for organizations like large hospitals, it will be hard for smaller clinics to make this purchase. Moderna’s minimum purchase amount is just 100 doses, allowing greater access to organizations needing fewer vaccines.
  7. Another thing to note is that each vaccine contains the active ingredient of the mRNA, but also contains inactive ingredients composed of lipids, salts, and sugars. These inactive ingredients maintain the pH and stability of the vaccine and allow for the delivery of the mRNA to the cells. The exact types and amounts of these inactive ingredients vary between the two.

If you are given a choice between the Pfizer or Moderna vaccines, hopefully you will now feel better informed about how they differ and empowered to choose between the two! No matter which vaccine you choose or you are offered, they are both incredible tools to help end the spread of COVID-19, and will offer excellent protection against the virus. Remember to continue wearing a mask and practice social distancing!

Be sure to check out the next post in the series where we’ll tackle common myths and misinformation about these vaccines and provide you with the science-backed truth!

2 Responses


January 27, 2021

Have you also researched the Johnson And Johnson vaccine which is considered a true vaccine or ivermectin


January 27, 2021

Thanks for this break down <3

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