While I want to believe the vaccines to be safe, Gendlin's litany tells me that it's more important that whether they actually are and the ability to change one's mind is a key feature of a rationalist. Another thread links to a discussion on the Dark Horse Podcast between Steve Kirsch, Robert Malone and Bret Weinstein about issues with vaccine safety. My prior for Steve Kirsch before that video was that he was one of the people in the world who thought most effectively about how to deal with COVID-19 in 2020. I hold that belief because of his project, the COVID-19 Early Treatment Fund.

The Fund describes it's guiding principles as:

The world has to take a multipronged approach to tackling COVID-19. We should work to identify effective repurposed drugs, validate experimental drugs, develop new drugs, test early treatments, test late treatments, try convalescent serums and invest in vaccines. We must do all of this in parallel to end the pandemic. 

The guiding principles document goes into more detail about their principles and is well worth reading. When I first read it I thought, this is actually a sensible plan compared to what governments are doing. It seemed to me also better than what various EA groups managed to come up with. When someone who run a non-profit that tells the world that it's important to invest in vaccines in its guiding principles tells you about vaccine side-effects and who managed to put their money into a sane COVID-19 response, that's to be taken a lot more seriously than most other possible people who might say something about vaccine side-effects. 

If the thesis is true, it's very important to know as soon as possible, because the thesis is about issues that are particular to the spike protein. If the thesis is true a step that's as simple as putting domains of the spike protein seperately into a vaccine or targeting a different protein for the third vaccination shoot might completely mitigate the side-effects.

Given that many rationalists are vaccinated and the thesis of Kirsch is that adverse effects to the vaccine are common, we would expect that if the thesis is true there are rationalists who face significant side-effects. While that still isn't a full proof of the thesis, it would increase our knowledge to know whether that's the case.

For a definition of significant side-effects where significant side-effects means effects that don't disappear after 3 days, who here thinks they faced significant side-effects? If you feel uncomfortable about attaching your identity publically to your report, you can message me about it and I will post answers anonymously.

New Answer
New Comment

16 Answers sorted by



1st shot of AstraZeneca: Fever for a week (shivering the first night and high fever the first day, then feeling feverish and temperature increased by 0.7 Celsius for about 7 days)

2nd shot: no side-effects



Pfizer. I'm not sure if I recall the first dose that well. There was some inflammation in my shoulder area, near the injection site. Kind of expected with all vaccines. Nothing else that made an impression on me.

The second dose was a bit worse. The inflammation resulted in some deeper, but mild soreness in the shoulder joint. I also noticed some mild lower-back soreness, perhaps in the kidney region. I did not bother taking any painkillers because it was pretty mild and didn't last very long. Maybe a couple of days, so not really significant. This was also within expectations.

Lately, I've been having palpitations, sometimes enough to cause some insomnia. Also some intermittent chest aches, but it's very mild. It was noticeable enough that I've been checking my heart rate more than usual. It seems a little elevated, even at rest, maybe in the 80 bpm range. I'm normally in the 70 range at rest, and can get down into the 60s when I'm very relaxed.

I thought nothing of it at first, because occasional palpitations due to stress are not unusual, and I had reasons to be stressed. But it's been unusually persistent for probably over a month now, even though I'm feeling less stressed than usual, which is more concerning. I don't recall exactly when it started, but it was definitely some time after the second dose. It probably started more than two weeks after (although I can't recall exactly) so maybe it's unrelated. It did not occur to me that this could be due to the vaccine until I saw that Dark Horse video.

I've been having similar long-term symptoms. Palpitations, frequent headaches, chest aches / trouble breathing. Also constantly slightly congested.

Started around 5 days after the first Pfizer shot, been going on for roughly 3 months now. It's hard to attribute definitely to the vaccine as I have other health issues that could explain most of these symptoms, and I'm also very out of shape right now. But the timing is very suspicious. It was really a very sudden worsening of my health, literally from one day to the next.

How was the first day after the shot?
1st day: soreness in arm 2nd-3rd day: strong flu-like symptoms 4th day: feeling completely normal 5th day: start of what I described.   I'll be happy to give more detail about my medical history in private.

Fun fact, 3 months after contracting Covid, I got heart palpitations and a persistent cough which have continued for 3.5 months. Maybe just age? I'm 40, working from home, no known environmental changes, no new drugs, no other symptoms, no history of similar symptoms (except colds, of course). 3-month delay suggests "not covid's fault" but...weird! (Update: cough gone after 4.5 mo but heart palpitations now happen nearly every waking minute and heart rate frequently elevated; still, I have no good reason to blame Covid. Elevated heart rate was actually the... (read more)

Sorry, I really can't recall. I'm probably more out of shape than usual due to mostly staying indoors for the pandemic year. Also higher than usual anxiety due to work recently. That could almost explain my symptoms, at least at first. That's why I thought nothing of it when it started, and also why I can't recall exactly when it started. I do have some sparse fitness tracker data from that period. From that, it looks like my resting heart rate became elevated the week of the first dose, and has persisted until now. The two months before that were noticeably lower. But that's going by just a few manual readings per month, which is inconclusive. I don't have the cough, but I had the vaccine, not the disease.
I do have some sparse fitness tracker data from that period. From that, it looks like my resting heart rate became elevated the week of the first dose, and has persisted until now. By how much did your heart rate get elevated?
February averaged 71 bpm. March 68 (only one reading though). April, the month of both doses, 81. May 82. June 80. So maybe by 10-13 bpm. The data is pretty sparse though.



Had Moderna. My first shot was worse than my second. The thing that surprised me -- I had a very specific kind of neuropathy that I like 90% recovered from in 2019, and some side-effects I had post-vaccination felt neuropathy-like. I don't know many people felt the same. I reported all of mine. They all went away in about 7-10 days, but it did happen.

I figured if non-replicating spike proteins can do this, then a virus that produces many more of them would do much worse. So I'm okay with having taken the vaccine. But I did have unusual side effects that may or may not have been related to previous nerve damage.



From another member that's also in the 25-100 karma range:

A family member of mine works in health care and has seen a representative sample of more than a thousand vaccinations and the side effects. Their impression is that the side effects are the strongest after Sputnik V, the weakest after Sinopharm, with mRNA-based vaccines being somewhere between the two. They reported no obvious cases of serious long-lasting side effects, only anecdotes of e.g. lasting loss of sense of smell that may or may not be linked to the vaccine. They has no experience in rationality.



I know about 16 vaccinated people I who I expect would have noticed+told me about easily noticeable >3 days side effects if they had occurred. 0/16 told me. Most mid-30s, two 60s. 40% W, 60% M. 80% basically healthy, 20% with significant health issues. Several groggy/sore/etc for a day, three very much so. Not sure about type distribution, though predominantly Pfizer.



Seems like you’re looking for anecdotes rather than data which strikes me as strange for a purported rationalist. The plural of anecdote may be data, but the quality of those data will be low. If it helps, I had one dose of AZ and had minimal side effects (slight headache, tiredness) that were gone in under 24 hours.

Seems like you’re looking for anecdotes rather than data which strikes me as strange for a purported rationalist.

There's a hypothesis in my post and I'm running a cheap experiment to disprove it. Absences of anecdotes would falsify the hypothesis.

If the hypothesis isn't falsified that would justify running more expensive experiments. Having detailed accounts of side effects in turn allows setting up expensive experiments in a more targeted way.

"Anecodates are not evidence" is a slogan that's quite fundamentally opposed to what this community that founded on ideas like everything is Bayesian evidence is about.

If it helps, 

It doesn't help for the experiment that I care about, but I'm not going to do anything to supress any data reporting.

At the least, I would have expected this to be a poll, so as to get a denominator.

5 data points: my household and two coworkers suffered from (at most) temporary sore arms (4 Pfizer, 1 Moderna). Oh, and a mild headache under 24 hours. Edit: 670,000 more datapoints.

Update Aug.1: after the same 5 people got a second dose, one coworker got strong Covid-like side effects for about 24 hours, starting 12 hours after vaccine administration; he basically took the day off in consequence. I'm unsure which vaccine he received. Among the other 4, the worst effect was short-lived, mysterious, temporary pain in various locations (24 hours or less).

A denominator doesn't help with falsifing the thesis. If we do get a bunch of reports of significant side effects and a bunch of reports of no side effects, the conclusion wouldn't be that the thesis is correct but that it deserves more expensive attempts at verification.  I don't see anything significant to be gained by having a dominator.  My thought process was: 1. I could run a mechancial turk experiment to get a representative sample and get representative numbers from that. 2. That would cost money and I haven't done it before, so is there an experiment that would falsify the thesis that's cheaper to run? 3. If the situations looks like what Kirsch is describing, we there are likely rationalist with signficant side effects. This not being the case, would suggest that the thesis of Kirsch is wrong. 4. Let's write question to get to know whether there are rationalists with significant side-effects. 5. If there are I might even get someone else to run the mechanical turk experiment ;)
Point taken. Even so, I'm concerned about the reputational and public-safety consequences of not simultaneously gathering "no side-effect" reports (conditional on the vaccines being safe).
If you look at this thread there are plenty of people who do post "no side-effect" reports. When people send me those reports privately, I do post them here even when it's not the information that's valuable to me.  Doing anything that would effectively stop those reports from happening would be bad.  The question is whether to do this as a poll or not and not stopping the gathering of "no side-effect" reports.  Optimizing for reputation instead focusing on truth seeking is dangerous. This kind of reasoning killed a lot of people in the last year.  It's not easy to choose truth seeking but in the end that's what the rationalist project is about. It's not like I don't have impulses in the other direction as well, but then I go back and optimize for truth seeking even when it's an effort and comes with risk. To get back to the poll question, there are two choices: 1. Have an anonymous poll. This opens us up to outsiders coming and creating a lot of false votes. 2. Have a named poll, this discourages people who might say something inconvient from participating. 
Excuse me? I'm not suggesting there's anything wrong with measuring the numerator. Methinks thou doth protest too much.
Irrelevant nit: the archaic second-person singular of "do" is "dost", as in "dost thou not know". "Doth" is the third-person form, as in "the lady doth protest too much".
It's a higher Simulacra level. Zvi wrote a lot about how COVID-19 decision making at higher simulacra levels lead to a lot of harm.
And in this particular case? How does shunning the denominator increase safety here?



Anonymous post from a user with between 25 and 100 karma (range wide enough to be anonymizing):

"A few COVID vaccine data points for you, from the people in my close circle that I know about.

Me, M, early 40s. One dose of Pfizer. No side effects. Mother, late 60s, F. Two doses of Pfizer. No side effects. Father, early 70s, M. Two doses Astrazeneca. No side effects. Brother, early 40s, M. One dose Astrazeneca. Reported side effects. Thinks it may have made him react to a spice in a meal he made. Colleague, mid 40s, F. One dose Astrazeneca (I'm unsure on that). No major sure effects. Reported feeling grotty / wiped out for a day or two.

There are several other people in my circle who have had vaccine doses by now where I think it's quite likely I'd have heard of they'd had adverse reactions, but I've not had specific conversations with them about it. So I'd assume most of them have had no significant reactions."

Surely a poll would be better -- easier for people to answer, less risky of bias.

Universally, accepted medical ethics according to which our system runs suggests that biases in the direction of finding side-effects of medications is generally good. Doctors don't report about every patient to VAERS but about those that are worth reporting about. I do think that for people with signifanct side-effects describing them is no unnecessary burden and those descriptions is what I'm looking for. A pure poll would better be done on mechanical turk, survey monkey a similar service that actually give you a representative sample. If someone wants to run such a poll I'm would be happy to see the results. A general LessWrong survey in the form of our previous survey that includes the standard questions of previous surveys while also including questions both about COVID-19 infection and side-effects while also including questions about vaccine's and side-effects would be another worthwhile project. It's a while since we had a survey and a survey that includes risks of both COVID-19 infection while also includes possible risks of vaccine would be very helpful for making useful decisions. 



Pfizer. First shot caused pain at the injection site that lasted about 24 hours. Second shot led to about twelve hours of what I would call moderately severe flu symptoms. Chills, exhaustion, headache (though one should note that the slightest breeze will give me a headache), brainfog. I basically slept all day, and woke up feeling fine the next morning.



My close family had 3 people receive 2x Pfizer, 1 2x Moderna, and 1 2x Novavax (part of a clinical trial). No side effects beyond muscle aches/fever/malaise for at most 24 hrs.

NB Novavax is not an mRNA vaccine; it's basically just the spike protein presented on an inactive substrate mixed with some preservatives/immune system agonists. A spike protein kebab, if you will.

Oh and add on to this some Israeli cousins (who all received Pfizer), at least 7? With the same side effects.

I haven't really taken stock of this before, but given how many people I know have received a vaccination the lack of reported long-term effects seems like a notable signal.



J&J (1 shot): mild tiredness the next day, no other symptoms.

Mateusz Bagiński



1st shot:
Mild headache after waking up on next day, gone by evening. At that time I gave it a 80% probability of being connected to the vaccine. The pain in my shoulder was much more annoying and lasted for maybe 4 days (but no inflammation or anything else worrying).

2nd shot:
Got it 3 days ago. I got headache again so the one after the first dose was probably also a vaccine side-effect. This time it was significantly stronger. Nothing debilitating, but it made me relatively lethargic and not very eager to do things. The headache stayed with me for the entire day, but was gone next morning. Shoulder area-effects similar to the first dose but possibly milder?

it made me relatively lethargic and very eager to do things

Lethargic and eager or did you mean "not very eager"?

2Mateusz Bagiński
I meant "not very". Thanks, edited.


I had fatigue, lightheadedness, and stiffness/aches for four or five days after the second shot. It wasn't that debilitating after the first two days but it sucked.

I don't regret getting the vaccine and I went in know I was probably going to be hit hard since I had similar (less intense) effects from the first shot.

Also... asking for anecdotes on a forum isn't a great way to gather data. A poll would be better, so you at least know how many people were fine.

Which vaccine did you get?

Pfizer, both times.

Bobby Shen


I acknowledge how late I am. I experienced chronic illness which was close in time after my second shot from Moderna around May 20, 2021. I had typical moderate acute side effects (which were far below anaphylaxis), which gradually decreased to chronic fatigue symptoms, lasting over 6 months. There is no biological proof of a causal relationship. My GP noted t hat there was a plausible mechanism of immune overreaction and nervous system (PNS/SNS) imbalance. One reason for the long duration of chronic illness was my lack of resilience to deal with everyday life activities (ADL) with chronic fatigue most mornings, since I am young and live alone. I have never had a community to share this with, only a few close friends here and there. I have had insufficient  medical support, but this chapter of my life has drawn to a close. After recovering, I have made several steps to mitigate future episodes of chronic illness. I'd be happy to follow up on this.



I received the Moderna vaccine.

I didn't note any side effects after the first shot, except maybe some mild soreness around the injection site, and, if that, delayed about a day from when I received the shot.

But I had pretty noticeable side effects from the second shot – significant fatigue/lethargy, muscle aches, and general 'crumminess', and for about two days afterwards.

But, per your criteria, I had no "significant side-effects".

8 comments, sorted by Click to highlight new comments since:

Note that answers here, on their own, will give a one-sided view of the side-effect situation which may mislead everyone's Systems 1. I am not suggesting that everyone who had no significant side-effects comment to say so because (1) in practice that won't happen, so answers will still be greatly biased but it may be less obvious that they are and (2) if it did it would mean way the hell too many comments :-). I will remark, since I'm commenting anyway, that I had two vaccine doses (AstraZeneca) with no significant side effects. (I felt grotty for a day or two after the first dose. I noticed no side effects at all after the second.)

Note that answers here, on their own, will give a one-sided view of the side-effect situation which may mislead everyone's Systems 1. 

If you believe that we should expect a certain number of side-effect reports even if there's no issue with the vaccine (and reacting it would mislead System 1), how reports of significant side-effects do you think we should expect? 

If you believe that we should expect a certain number of side-effect reports even if there's no issue with the vaccine (and reacting it would mislead System 1), how reports of significant side-effects do you think we should expect?

Are you asking for effects that show up after 3 days (and then don't go away), or anything bad that happens sometime within a couple of months after getting vaccinated? 

If it's the latter, then among1,000 people you might expect that a few people will have weird health issues show up without an obvious cause. I'd be surprised and pretty concerned if someone died in that interval (for non-obviously traceable causes), but if it was just a handful of issues of the severity of "developing a kind of serious new allergy" or "developing heart rhythm issues," that could be entirely what's expected (though I haven't studied the frequencies).

With miscarriages, for instance, apparently "1 in 8 pregnancies end in miscarriage" – so out of a large enough pool, you have to expect that someone had a miscarriage in the last couple of months, etc. 


My father, mom and brother had no significant side effects after two doses of either Pfizer or Moderna. I'm only 3 days after my first dose of Pfizer; no side effects so far.

My father's a GP and seemed happy that I'm getting vaccinated – though he did say that it's possible for young people to have "kind of scary 2 days," side-effect-wise.

(Also have friends in the community who didn't have issues from 1st doses, but was focusing on people outside.) 

Update: My girlfriend felt unusually tired (and maybe some brain fog) for 5-7 days after the 1st dose of Moderna; the effect went away after that period.

Are you asking for effects that show up after 3 days (and then don't go away), or anything bad that happens sometime within a couple of months after getting vaccinated? 

Deciding what's a vaccine side effect and what's not is up to the person who answers and the target audience is rationalists who I expect to make reasonable decisions. 


Two Moderna doses here with no significant side effects

I had two doses of the Pfizer-BioNTech vaccine. I experienced a sore arm that went away after ~1 day after the first dose and moderate aches and chills that went away after ~12 hours after the second dose. 

I know around 10 people in my age group (20-35 years old) that have gotten one of the MRNA vaccines and none of them had a significantly more severe reaction than I did.  

One Pfizer with no side-effects.

1st dose (Pfizer): Mild soreness at injection site for ~6 hours (similar to flu shot).

2nd dose: same