This is related, but feels like a question for a new thread…
Some of us (raises hand) get really sick from annual covid shots. Last year i had a fever and chills and malaise for two days. This year it was much less bad, but my arm was so sore i couldn’t use it (brushing my hair was a challenge) for a few days. I was considering skipping the annual update this year, but my doctor pointed out that my husband’s cancer treatment makes him immune compromised. I did seek out nextspike, which has a smaller piece of antigen.
Anyway, if you get that kind of reaction, is it generally a sign that your immunity is enough, and you should skip the booster? Is the nastiness an unrelated immune response? Something else?
My feeling is that the purpose of the vaccine is to inveigle your body into thinking it is being attacked so that, in response, in produces the necessary immunity. That strongly implies to me that a reaction is not only normal but also to be expected.
Some reaction is expected. I got a flu vaccine last night. The arm was sore for a while, and then itched for a while. Today, it’s a little tender near where i was jabbed. That’s a fine, reassuring kind of reaction. Similar to my reaction from my very first covid shot.
Two days of chills and fever seems a bit much. And it was getting worse every year. And this year, it occurred to me that if the reaction had been broader, and not limited to one arm, i would have been disabled. If it had affected my chest muscles, i might have needed hospitalization for breathing support.
I had similar symptoms after my shingles vaccinations: fever, chills, headaches, and fatigue. The first vaccination was a little milder, but the second was very severe. It seems to be normal; doctors predict these symptoms.
You don’t need to worry about disability or respiratory arrest; the symptoms are temporary, and this also applies to the COVID vaccination.
I used to have the same reaction as you do. Not as bad with the Flu or Shingles vaccines, but definitely with the COVID-19 vaccine. I asked my PCP, and he said it was because my immune system was so strong. I didn’t buy that and talked to my Endocrinologist. He said it was because the vaccines were putting stress on my immune system, and because my cortisol level was low, which is why I was getting so sick. He prescribed me Hydrocortisone, and when I took it for my flu and COVID shots this year, I had no adverse effects. Zero. Nada. It turns out I have a rare genetic disease, and apparently, this is my only symptom. The problem for me is solved, at least for now.
This is interesting. How strong is the association between cortisol levels and severity of reaction to a given vaccine, I wonder?
My cortisol level is high, and the COVID vaccines have only left me fatigued for about 12 hours – and even that is a delayed reaction (takes about 12 hours to hit). I get no reaction from flu vaccines at all.
Sometimes. When a vaccine triggers a response from your immune system, immune cells go to work to fight the antigen. If there is a strong immune reaction, you might feel tired or experience body aches, headache, swollen lymph nodes (glands) or even a fever.
These side effects seldom last more than a day or two and do not mean you are sick. They signify that the vaccine has successfully activated your immune system.
If you do not have any symptoms, it does not mean that the shot was unsuccessful. A vaccine without side effects can still activate your immune system and protect you from disease.
Covid vaccines have had a relatively short history. I’m not sure there have been any studies on the long-term effects of yearly boosters. Could there be some cumulative effects going on here? I suppose that’s possible. After getting the initial two shots and a first booster, I have stopped getting Covid shots due to the reactions I was getting from them seemingly worsening as well.
My doctor looked about 6 months ago, and couldn’t find any relevant studies. There is obviously a cumulative effect. Because there have been no studies on the covid vaccine, specifically, I’m curious if anyone knows anything based on other vaccines.
Yes, i knew the problem was temporary, but my arm was so sore that there were things i couldn’t do for a few days. If you can’t breathe for a few days, and don’t have major medical intervention, you die before the effect wears off. It came on fairly slowly. If it had affected my diaphragm and chest muscles, i could have gotten to a hospital in time. Still, i wonder if i should continue doing this.
About 12 years ago I got Guillan-Barre Syndrome. It is an auto-immune disorder that attacks the nerves. It is not contagious at all, just happens to some people. The cause is uncertain but it was speculated that immunization shots might be a possible cause. They rev-up the immune system and the immune system attacks things you do not want attacked.
I did not have a vaccination for years after that. Indeed, when I went for one once they handed me a sheet with two questions. I forget what question #2 was but the first was something like, “Have you ever had Guillan-Barre Syndrome?” I checked yes and they noped me right out of the room.
I am not opposed to vaccines at all. I WANT to get vaccinated. But I need to be careful. I did do COVID vaccines because those seemed important to get more than my yearly flu vaccine and I have not had a problem with those. I still avoid yearly flu vaccines though.
ETA: To be clear, it is not proven that vaccines cause Guillan-Barre Syndrome…it was mostly a guess and does not mean you should not get vaccinated (the syndrome is pretty rare). It does mean, for those who have had it, to be careful about vaccines in the future since they know they might be affected. Still best guesses though.
I’m not suggesting getting sick after getting a COVID vaccine is because, like me, they have low cortisol levels. (When last tested, my fasting cortisol was within the normal range, but my ACTH level was elevated.) Under normal circumstances, my adrenal glands produce enough cortisol. It’s only when my immune system is challenged, such as during a sickness or after a vaccination, that the problem occurs.
I had my Fall 2025 COVID vaccine yesterday, and took 2 10mg hydrocortisone tabs 1 hour before and 4 hours after. I also took some low-dose hydrocortisone (10 mg) last night and this morning just to be sure, but I probably didn’t need it. So far, I feel great. The key for me is to take it preemptively, not wait until I feel sick. Taking the cortisol in advance supports my immune system and helps it prepare for whatever stress it’s about to face. YMMV.
The COVID-19 vaccines, and especially the mRNA vaccines, seem to provoke strong reactions in some people. While this is an indication that the adjuvants in the vaccine are stimulating an immune response, the strength of the response is no indication of the durability of immunogenicity or the degree of protection engendered by it. The SARS-CoV-2 coronavirus which causes COVID-19 mutates rapidly (all viruses will mutate but RNA viruses have a particularly fast evolutionary pace), and like influenza viruses will undergo reassortment and recombination to evade established immune responses and present novel pathologies. It is also known that the protection offered by COVID-19 vaccines wanes over a period of months in many if not most people even against the variants of the virus it was designed to protect against, so if you have a reason to be especially concerned about infection it is wide to continue to get ‘booster’ shots. (These aren’t really ‘boosters’; like the influenza vaccines, these are reformulated to protect against the most recent variants of the virus found in circulation.)
All of that said, there is still a lot that is not well understood about the SARS-CoV-2 virus (and betacoronaviruses in general, which weren’t studied very intensively before the 2003-4 SARS-CoV(-1) and MERS-CoV outbreaks). I have a virologist friend who studies betacoronaviruses and she’s still concerned for the potential for SARS-CoV-2 to develop into a pathogen with the virulence of its betacoronavirus cousins even though that hasn’t been seen thus far. She correctly points out that if SARS-CoV(-1) had a transmissibility of the (-2) virus, we would have a pandemic unseen in modern history, and if MERS-CoV were readily transmissible between humans we would be facing a Variola major smallpox-like threat with a naive global population.
My wife and I will often get the same vaccinations at the same time. I will have little to no reaction while she is knocked out for a day or so. She has to plan for downtime to recover. She gets a fever, is super tired, sleeps for hours, etc. It’s almost like she actually has the flu. It happens with both COVID and flu vaccines. I find it interesting that we have such different reactions to the same exact injections. It mirrors how we react to getting sick in general. Typically, I will have mild symptoms and may not have much downtime at all, but she will often be on bed rest. In her case, it seems like her symptoms are much more from her immune system overreacting rather than the intruder destroying cells and doing other damage.
No field in medicine––even neurology and neurophysiology––has as many “unknown unknowns” as immunology and allergy. Frankly, aside from specific pathologies and genetic maladies, modern medical science has little practical understanding of the causative mechanisms behind why some people have severe responses and are prone to infections, and others are not. The innate and adaptive immune systems are an amazing emergent capability of evolutionary biology that we have only just scratched the surface on understanding.