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Best of 2021: Comparison of Three Coronavirus Vaccines

Dec 30, 2021 8:00 am

On Feb. 27, the Food and Drug Administration announced it has issued an emergency use authorization for Johnson & Johnson’s one-dose Covid vaccine, making it the third COVID-19 vaccine to be commercially available.  We've compiled a comparison table and some key information relevant to your delivering patient guidance henceforth. 

Key Caveats

  • Important to note that COVID vaccine efficacy varies by country (generally higher in the USA) and with the age group under study (sometimes lower in elderly individuals)
  • None of these are live or replicating vaccines.
Comparison of Pfizer, Moderna and J&J COVID-19 Vaccines
ManufacturerPfizerModerna J&JAstraZenica
EUA approval12/11/2012/18/20 2/27/21 Not submitted
TypemRNAmRNAAdenovirus vectorAdenovirus (modified)
Number enrolled43,54830,42043,783NA
# Shots/interval

3 weeks


4 weeks

(2 doses under study)


4-12 weeks



86% >65yrs

66% Globally

72%   USA

Protection against Severe Dz92%88.9%85% 
Protection from COVID Death85%(6 deaths)100%100%
Protection from COVID Hospitalization87%89%100%100%
Storage Temp- 94°F-4°F36°F and 46°F36°F and 46°F

  • None of these have been studied in children. Pfizer’s vaccine is approved for those over 16 years, while the other 3 have been studied in adults > 18 yrs.
  • None of these have been studied in autoimmune, or immunosuppressed or pregnant individuals
  • "Reactogenicity" (referring to transient mild to moderate adverse effects) may occur in the first 7 days and include: injection site pain, fatigue, headaches, myalgia, arthralgia, flu-like symptoms.
  • With Pfizer and Moderna vaccines, side effects were more common after the second dose.
  • Side effects were more common in younger adults, and less so in older adults
  • Anaphylaxis is exceedingly rare, but occurs usually within 15 min of injection; hence the reason subjects are advised to be observed for a short period after injection.  Reported anaphylaxis rates: Moderna: 2.5 cases per one million doses; Pfizer: 4.7 cases per million doses. Some have suggested that anaphylaxis and more severe reaction are more likely in those with a history of severe allergies or prior anaphylaxis
  • CDC recommends that "if you have had a severe allergic reaction (anaphylaxis) or an immediate allergic reaction—even if it was not severe—to any ingredient in an mRNA COVID-19 vaccine (such as polyethylene glycol), you should not get an mRNA COVID-19 vaccine".
  • Vaccine stability: once the Pfizer vaccine vial has been thawed, it must be used within five days; Moderna’s is stable at fridge temperature for 30 days and at room temperature for 12 hours. J&J’s vaccine can be stored at room temperature for 12 hours d that information
  • There is no data on the durability of protection (how long am I protected?)

Editor's note: This blog post appeared March 10, 2021 and is being published again today as part of RheumNow's Best of 2021. 

The author has no conflicts of interest to disclose related to this subject

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