Moderna and Pfizer vaccines: Similarities and differences

A vaccine from Moderna has been approved and will soon be providing an additional option in COVID-19 vaccination

A closeup of a sticker on a man's athletic logo sweatshirt that says "I got my COVID-19 vaccine!"

The COVID-19 Pfizer vaccine that hit the region recently will soon have company from Moderna.

The two vaccines are not exactly the same but they work the same way and accomplish the same things, health officials say.

The steps toward FDA approval and distribution for Moderna’s vaccine were the same as they were for the Pfizer vaccine that is now in use in the Sanford Health system.

“We are ready to handle either vaccine at any of our locations,” said Jesse Breidenbach, Sanford Health senior executive director of pharmacy. “We are ready for fluctuations in supply of either from either manufacturer. By doing it this way, we can vaccinate patients based on what’s available, not just based on how and where we can handle either vaccine.”

Things to note about Moderna vaccine:

  • An FDA review of Moderna’s clinical study confirmed the vaccine is more than 94% effective in preventing COVID-19. (In a similar study, Pfizer’s vaccine was 95% effective).
  • Like the Pfizer version, Moderna’s vaccine comes in two doses. The second Pfizer dose comes 21 days after the first. The second Moderna shot comes 28 days after the first.
  • It follows the same FDA Emergency Use Authorization (EUA) process used with the Pfizer vaccine.
  • Unlike the Pfizer vaccine, it does not need to be kept in extremely cold temperatures while stored.

Easier storage

Undoubtedly, the vaccines’ main difference are the storage requirements. Once the Pfizer vaccine is removed from cold storage (-70 C), it remains useable for five days when stored at normal refrigeration temperatures.

The Moderna vaccine can be stored at -20 F, or normal freezer temperatures. Once taken from the freezer it has a shelf life of 30 days when stored at refrigerator temperatures (36-46 F).

“The storage system is much simpler,” Breidenbach said. “We will still be tracking the temperature of both, however, through the entire life of the vaccine until it reaches the patient.”

Either works

Health officials are not picking sides on which vaccine to take. Availability should be the ultimate determining factor, Breidenbach said.

“The technology for the Moderna vaccine is very similar to Pfizer’s,” Breidenbach said. “The efficacy is similar and from what we know now, the minimal side-effect profile is similar.”

The vaccines share another key factor: You have to get the shots for them to work.

“Obviously every one needs to stay vigilant with social distancing, masking and hand hygiene as we move into what we hope is the final stage in our battle against COVID-19,” Breidenbach said. “But the vaccines won’t work unless we use them. We need a good rate of acceptance.”

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Posted In Coronavirus, Frequently Asked Questions, Immunizations

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