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Super Contributor

Delayed onset reaction to Moderna vaccine

I just wanted to let people know about a reaction I got at the site of the injection 8 days after I received it. Nobody says anything about this, probably because only 0.8% of trial recipients got it and they haven't done enough research yet to see what causes it.

Here's a website about it that I found:  Delayed Large Local Reactions to mRNA-1273 Vaccine against SARS-CoV-2 | NEJM. It's not serious, but I hadn't heard anything about it so I was unsettled when I got it. I reported it to my doctor, VAERS, and Moderna.

Not applicable

Hi @srk5cats it happened for my first Moderna. The itching made me roll my long sleeves up before scratching too much. Glad I did as I probably would have done some damage to vaccine site with my nails. I went online and they said to use an ice pack, hydrocortisone cream or benadryl. I had the first two and my stomach does not like any over-the-counter meds. So I try to avoid them when possible. Yes, the bright red scared me but all was back to normal in about a week. I was told it was a DELAYED allergic reaction. Thank goodness it didnot happen with my second vaccine 🙂 Glad you posted this so folks will know.

Recognized Social Butterfly

For itching that doesn't respond well to scratching, try 4% lidocaine cream that is sold OTC for muscle aches.  I add 1% pramoxine in isopropanol but I don't expect you to do that.

Honored Social Butterfly


Did it look kind of like this?  It is pretty common now - in fact, they are even calling it "Covid arm" or "Moderna arm" - I had it with my 1st Shingrix (Shingles) vaccine.  Itched like crazy - then just went away. I did NOT have it with my Covid-19 vaccination (Moderna) course my 2nd one is just now coming up.   It is just another immune response that some bodies give off.


delayed skin reactions to the Moderna vaccine.

It's Always Something . . . . Roseanna Roseannadanna
Super Contributor

I've never had a reaction before to a shot, so it scared me. They are also calling it "Vaccine Arm". I haven't had a Shingles shot yet. Mine looks similar to yours except I don't have spots and it's not quite as big. Do you have allergies?

Honored Social Butterfly

@srk5cats wrote:

I don't have spots and it's not quite as big.

I figured out what the spots are surrounding the red rash area in the photo - don't know where my brain was before -

The dark spots you see on the subject's arm in the photo are marks on the skin placed there to determine if the rash is moving or getting larger/smaller, etc.  Just a way to monitor it.

It's Always Something . . . . Roseanna Roseannadanna
Honored Social Butterfly


No mine didn't have spots either - could have been that picture - I have a better one in my file but that was the 1st one I found on the web - it came from Mass General based on the NEJM article that you posted dated about the 1st part of March.

I had never had it before either - it didn't scare me so much since it seemed to be so topical - I didn't have it with the 2nd Shingrix shot - just the 1st one.  And I had absolutely NO reaction to the 1st Moderna - not even a sore arm.  I was prepared for a down day or a couple of them - but nothing.  I take the next one on April 06.

Mine reaction was pretty large and it worked its way down towards my elbow - started about 5 days after my 1st Shingrix shot then it got red, swollen, felt warm to touch - each day it got better and better - if not for the itching I actually felt nothing.

I used aloe and took some benadryl - yes, I have some allergies but mostly to airborne stuff like pollen - all upper respiratory not topical.

Yes, it was weird.  You are wise to post about it here.

It's Always Something . . . . Roseanna Roseannadanna
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