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Pfizer vs Moderna – what are the differences?

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As we all hold our breath waiting for the one dose Johnson and Johnson vaccine to come out (more on that later) we are waiting for our turn to get either the Pfizer or Moderna vaccine. We covered how they work last week, but if they are using similar technology, what really is the difference?

This week, we’ll break down the Pfizer Vaccine vs Moderna. Well, effectiveness for both is pretty great. Pfizer states they are 95% effective and Moderna is 94.1% effective. Not too different there. They both require a second dose, so still quite similar. However, the timing between dosing is a little different: Pfizer has a 21 day separation between doses while Moderna has 28 days between doses.

Side effects for both are common…but are generally mild.. The most common reactions are injection site pain, fatigue, headache, muscle and joint pain, and fever (usually lasting 24 hours). The second dose is generally more likely to illicit such a response, but it is not indicative of a bad vaccine. Rather, it is evidence that your immune system has seen this intruder before and now knows what to do.

Some people have had anaphylactic reactions!!  Yes. And I’m not saying that wouldn’t be a terrifying ordeal to go through. However, the percentage of people with such a strong reaction are rare and to be expected when ANY type of medication/vaccine is given to such a large number of people. Someone will have a reaction. Thankfully, again, it is not a common occurrence.

Pregnancy. Well, the common denominator for both is that it is not recommended for pregnancy but should not be withheld from a pregnant person who is at high risk and eligible for the vaccine. Moderna states that there have been no issues in animal studies. Pfizer has not yet completed animal studies but states that no evidence of fetal harm exists thus far.

Storage. Very different here. Moderna ships at a chilly -4 degrees F. Scarf and hat weather in New England, no big deal. Pfizer, on the other hand, needs to be shipped at -94 degrees F. Frankly, there are not enough scarves and hats for that. Thankfully, they will not inject this arctic blast right into your arm and it will be thawed and able to be used over the next 5 days. Moderna is stable at fridge temperatures for 30 days and room temp for 12 hours.

Neither vaccine is approved for use with children…yet. Studies are ongoing. Right now, Pfizer is 16 and up while Moderna is 18 and up.

Who should NOT get the vaccine? Restrictions are the same for both: If you are allergic to any of the components of the vaccine, like   polysorbate you should not get the vaccine due to cross reaction to polyethylene glycol. If you had a severe allergic reaction to the first vaccine, you should not get the second.Thereis absolutely no such thing as a 100% risk free medication or vaccine. They don’t exist. However, the risk and impact of the actual disease needs to be weighed against the risk associated with the vaccine.

We recommend vaccination. It saves lives and will hopefully get us back to some semblance of normalcy. If you have doubts or reservations, these are valid and should be discussed with your health care provider. We’re happy to have a conversation with you, anytime.

Until next week, stay safe, wear your mask, and wash your hands 😊

 Brooke Rieth, NP and Action Medicine team

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