I received my two doses of the Pfizer vaccine back in April/May. The first shot made my arm just a little sore, but the second shot laid me low for a day: dizziness, a kind of “full head” feeling, mental fog, serious lethargy. Based on the news around that time, these sorts of side effects after the second dose were not unusual.
What makes the side effects of this vaccine so much worse than, say, the flu vaccine?
First, some people do experience those side effects from the flu vaccine; conversely, not everyone experiences what you did with the COVID vaccine.
Second, the flu vaccine has been around a while, so the producers have gotten much better about proper dosing to minimize effects while still being effective. The COVID vaccine is brand new.
Third, when I got my second shingles vaccine at the same time as the flu vaccine, my symptoms were much, much worse than when I got the COVID second dose or booster.
Fourth, as a two-dose vaccine, it’s re-priming your immune system for something that your immune system already learned how to fight from the first dose. So, the immune response is stronger, leading to those side effects. The flu vaccine is a single dose.
Those are my guesses.
It’s a question of particular interest to me at the moment.
First vax Pfizer in March, sore arm.
Second vax Pfizer in April, sore arm, the worst chills I’ve ever endured in my life, vague headache, muscle aches, joint aches, full head. For three days. Woke up on the first day craving coffee amidst the chills. It helped.
Third vax Moderna booster yesterday, chills but not as severe as before, headache, muscle aches, joint aches, full head and slight nausea. Also the coffee craving returned, and I’m happy to say it still helps. I don’t care if it’s a placebo effect. My hope is that the worst of it will be over by tonight, but I’m ready for another three days.
I’ve never seen any clear research on why the vaccines affect people in such radically different ways. I have a notion that how your body responds to the vaccine is an indicator of how bad you might suffer from the full-blown disease if you got it. The only “evidence” I have for this assertion is how much was made of the Cykotine Storm response the body may have to this virus early in the pandemic.
Since I suffer from several conditions associated with a hyperactive immune system, my response to the vaccines seems right in line with that.
Obviously empirical and not at all conclusive, but I’m interested to see if that possible link is borne out in research.
Pretty sure these are NOT harsh side effects. Those are inconvenient and uncomfortable side effects.
Harsh would be; ongoing vomiting, unable to keep down food, shivering with fever over an extended time, blinding headache without relief, debilitating body aches, etc.
Just sayin’!
Fair enough, but if you’re one like me who is rarely ill at all, the side effects feel harsh. But certainly not anything like catching the disease.
My observation is that reactions to vaccinations vary drastically. Anything that kicks up the immune system might cause a reaction anywhere on the spectrum. For me, the first two Pfizers were a flu-like for 3 days, but not even on the same severity planet as Shingrix.
If I’m not mistaken, they’re not side effects of the vaccine itself, but rather the results of your immune system’s reaction to the vaccine. Put another way, your body’s immune response is what’s causing the side effects. And since we’re a naive population, our immune response may be more pronounced than against something we may have had before, or that our forebears evolved with.
The thing is, immune responses are pretty unpredictable and vary widely across people. My wife and I got the same exact vaccines (same vial even) within seconds of each other both times, and we had fairly disparate experiences for each of the 3 doses we’ve had so far.
I’m not sure how you could have something like a vaccine without running the risk of having a fairly wide range of side effects, since everyone’s response will be a little bit different.
Interesting theory.
I’ve gotten the flu shot every year since 1986 (the year my asthma, largely at bay for years, became an ongoing concern again). That year, the flu shot was a double one - two different shots. I felt wretched off and on for several days. Every year since then, the worst I’ve had to deal with was a sore arm.
The one year I had the flu DESPITE being vaccinated was in the late 1990s. I was only in the “I’m afraid I might live” zone for 12-24 hours - may have been milder due to the vaccine, or I may just have gotten a “mild” case. After that, I did have a bronchitis / asthma flare, which could have landed me in the hospital if untreated - but most people don’t have that component, so we’ll ignore that.
My husband also got flu that year - and felt wretched for 24ish hours, then was slowed down another day or two. So, another mild-ish case.
Compare our reactions to the COVID shot, though: we both had Pfizer, and have gotten boosters. Me: 1) sore arm (took some Tylenol on day 2); 2) sore arm (no meds needed), 3) sore arm (no meds needed). Him: 1) sore arm, felt under the weather; 2) sore arm, felt really under the weather, 3) sore arm, felt bad enough to go to bed for a day.
Sample size of 2 - but similar reactions to flu shots, similar severity of flu case, very different reaction to COVID vax.
I asked my doctor about my very mild reaction to the Covid shot, as I was worried this meant it hadn’t worked as well for me. She said that studies are showing there’s no correlation between reaction severity, and immune response to the vaccine - quite a relief for me.
My personal theory re side effects - based on nothing scientific, of course - is that at least for some people, it’s because this is SUCH a new pathogen to the body, and the immune system basically screams “ZOMG STRANGER DANGER STRANGER DANGER DEPLOY ALL TROOPS!”. Mine, on the other hand, sits back, puffs on a stogie, and mutters “Yeah, yeah, another new virus, I’ll throw some bleach on it and get on with my day”.
Does how you react to the vaccines say anything about your immune system? I experienced very mild side effects - I felt a little tired and off after each dose, but no big deal. What does that say about my body/immune system vs someone who experiences more severe effects?
None, apparently, at least according to one doc. Which is why I referred toiit as a notion of mine and not a theory – or even a hypothesis! 
I had the 2 shot and then the booster, on all 3 shots within an hour I could barely find where they jabbed me, no swelling, sore arm, warm spot, other reaction that I could discern. I have been getting the flu shot every fall for about 15 years and in those 15 years had no ill effect from the shot nor did I get the flu [or anything that could possibly be the flu]
Doesnt mean that I won’t turn around and end up with covid or a variant - but I can be hopeful that if I do it will not be as bad a case of it that I might have gotten without the jabs.
As a counterpoint I’ve had 2 doses of Moderna and has no reaction either time and even though the needle itself was small enough that it didn’t hurt/cause a sore arm.
I’ve heard that repeatedly from friends who’ve received Shingrix vaccinations. I’m sure sorry it was so rough on you!
For now at least, I’m going to give that one a pass and take my chances. I didn’t have chicken pox when I was a kid, never had a cold sore or herpes or any other indication the virus is in me. I know how awful shingles is. My stepmom had a dreadful case. Twice, if memory serves. Still…
I’m open to being convinced, but so far, no one’s pushing me on it or even raising a gentle concern. Will let it ride for now.
Glad that one is in your rear view mirror.
Side question, how much worse is the 3rd shot than the 2nd? I’m getting my 3rd today but also have a lot of driving and piano-playing to do in the next few days, and am hoping the side effects won’t hamper my arm movement.
For me, the third was a half-dose booster and wasn’t as bad as the second, although I did have a mild fever, felt tired, etc.
I had strong reactions to the first two, and none to the third beyond mild soreness at the site.
Bleh - I’m due for my second Shingrix any day now (it’s been just over 2 months since #1).
While my reaction to the first one was, typically for me, mild (sore arm - though it did last longer than Covid / flu), I’ve heard the second is worse.
Two doses of Astra Zeneca (about 12 weeks apart) and then the Pfizer booster six months later. The UK had been doing longer gaps between jabs on the understanding that this is more effective, but I don’t know if that’s still the scientific consensus.
The first AZ shot hit me hard, with a high fever lasting 24 hours and all the fun symptoms that come with that. After that I was fine. No notable reaction to either the second shot or the booster apart from a mildly sore arm for a while.
The spouse had Moderna and a reversed reaction to the first two - nothing for the first one and the fever for the second. She had a sore arm for a week after the Pfizer booster but I think it was just badly administered as she had a massive bruise on the spot. Sometimes the person jabbing you gets it wrong.
Shingles is FAR worse than any reaction to the Shingrix vaccine. Orders of magnitude worse.
1st shot - Astra - pretty miserable for 8-12 hours
2nd shot - Pfizer - 8 weeks later - pretty miserable for 8-12 hours
3rd shot - Pfizer - 6 months after 2nd - about 20 hours ago - slightly sore arm at injection site