Pfizer vaccine and possible bonus?

This might be too much information but I’m putting it out there anyway just in case.

I had the Pfizer vac almost 2 weeks ago now, since then, I am happy to report that I have been able to go to the loo every day as regular as clockwork ever since! I have absolutely no idea what the connection might be but at the age of 63 that amounts to remarkable regularity when I’ve had a lifetime (30yrs ms wise) of irregularity and constipation. I have changed nothing else diet wise, just wondering if I’m the only one?



Brilliant news and hope this welcome side effect is permanent.

That’s great news Elaine. As a regular laxido user, I’m happy for you.

I had the astra zenica and after a few hours the following morning of feeling whacked out, I slept it off and then for almost 2 weeks felt renewed energy…back to normal now though.

It felt amazing to gain energy again.


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wonder if the vaccine ‘fired up’ the immune system ???

Hope someone somewhere is recording the effects the vaccine has on ms-ers.

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wow. maybe they have accidentally discovered a cure for MS!

hope so, 12 years in and I’m getting fed up now.

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I am very glad for you, but sorry to report that it isn’t doing the trick for me. :slight_smile:


Thanks for your replies everyone. I know it sounds to be a huge stretch of the imagination, but I can think of absolutely nothing else that has changed in my humdrum existence.


Wow indeed Elaine,

Thank you so much for posting this. I’ve actually had a horrible week with bowel problems following my Pfizer vaccination. I’ve been unsure whether the vaccine had anything to do with it or if it’s just my rotten bowels causing trouble (again!)

This may well be put into the box marked TMI, but I’m going to tell you all anyway!

(**Poo alert for anyone with a sensitive constitution ** stop reading now **)

Some of you already know that I had a colostomy 3 years ago due to my chronic constipation. I’d tried everything to resolve the constipation. Movicol (aka Laxido), Senna, Peristeen, micro enemas, and finally (for several years) digital rectal stimulation. Nothing worked, I had terrible haemerroids, a very nasty rash that was intractable and was in a really bad way because of it.

So the colostomy / stoma worked for me, although it hasn’t been all plain sailing, diverting poo from the regular route to a stoma isn’t without its own rather lovely challenges!! (I wrote a history and kind of diary of the process for the forum members; if you want to read my story, use the search box and look for the thread titled My Colostomy.)

But this week has been probably the worst time. I had the Pfizer Covid19 vaccine on Tuesday afternoon. By about 9pm my stoma pouch needed changing (stoma collection pouches are generally changed once or twice a day). It produced the most dense, compacted thick long sausage of old poo - about 6 to 8 inches long. This was followed by some softer poo with lumps in, and then a touch of diarrhoea and blood (bowel tissue bleeds very easily, so the blood’s not that unusual). In all, I’d spent about 2 hours in the bathroom waiting for the stoma to stop production before going to bed at about 12.30.

By around 2.30am I was awake, back in the bathroom and dealing with a repeat performance. The same dense old sausage of constipated poo that looked like it had been in hiding for weeks or even months. Another 2 hours getting cold, having a spasming back and generally hurting. I needed a pile of drugs when I managed to go back to bed at about 4.45. I then slept till 9.30. (Thanks medication!)

The following day, it seemed to be all over, until that night. A complete repeat of the Tuesday night, two separate incidences of dense old constipated matter, followed by diarrhoea and blood. Once again I spent over 3 hours in the loo dealing with the horrible stuff.

Then came Thursday. Super diarrhoea day. Through the day 5 separate incidences of awful diarrhoea, together with loads of blood. I must have spent about 6 hours in the bathroom just dealing with the horrible, (sometimes projectile) diarrhoea. Eventually it stopped and I actually managed to spend the night without having to spend hours in the bathroom. By Friday morning I thought it was all over. It was almost, but not entirely.

Yesterday late afternoon I spoke to my GP about my experience and asking whether it could have been related to the vaccine. ‘Unlikely’ was his thought. But possibly a stirring up of the immune system causing the bowel to try its hardest to empty out historic constipation. (As you thought Cracowian!) He did say that in the clinical trials, there were reports of diarrhoea/bowel related side effects. Although there were just as many similar events reported in the placebo group of the trial participants. So there are no expectations of diarrhoea being a recognised side effect.

Today, the diarrhoea is almost over, but it’s not quite not over either. I’m trying my best to ignore it for as long as possible because the various events of the week have caused some real trauma to the stoma. I want to give it as long as possible to heal. I know that when I change the stoma pouch there will be a considerable amount of poo/diarrhoea and blood. I just want to avoid too much traumatic damage to the stoma. Luckily the stoma and bowel do tend to heal up once left alone.

So, the end result is that the vaccine could just possibly have stirred things up. Personally I’m hoping it’s not permanent in my case, while simultaneously wishing it would be permanent for you Elaine. Regular bowel movements must be lovely. I’m almost envious (if that’s not utterly weird!!)

If there are any more people who’ve had similar experiences, please let us know - anonymously if you like. It’s not everyone who have found it as easy to discuss their bowel troubles in public. Believe me, it’s taken years and some dreadful experiences to be this open.



Oh no Sue!

How selfish of me to even suggest it was a bonus. I just want to give you a massive ‘virtual’ hug now. I’m so sorry for what you’ve been through and keeping my fingers crossed that everything might be stabilising for you? I was obviously the other end of the spectrum from you bowel wise - and I have always said that I would need dynamite to get me moving…be careful what you wish for maybe. Please look after yourself and feel free to cite me as evidence for your next disbelieving GP comment and thank you for sharing.



It’s not selfish in the slightest. It is truly a bonus. I really do hope it continues. Badly behaved bowels (from either end of the spectrum) are bl00dy miserable to live with.

If the Pfizer effect (assuming that is the cause - which isn’t proven for either of us!) doesn’t last, I suggest you could use this experience of having obedient bowels as a spur to get yours sorted out! Speak to the bowel and bladder service for help? Try different ways of approaching the problem? Dietary, supplements, movicol, lactulose (urgh), suppositories, micro enemas, experiment & see what works.

Best of luck to you and your bowels!!


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I had the Pfizer two weeks ago and my bowels have been functioning like clockwork! I’ve previously been on all sorts of laxatives and the only thing that worked was prucalopride. Previous to the vaccine I would have a BM every 8 days or so!
Did the vaccine effect wear off?

I had the pfizer and no effects at all


Thank’s so much for your kind words! I’m sorry to be SO late in response but just wanted to let you know that I am ticking along quite nicely since the ‘Pfizer ‘predictable’ effect’ much better than before certainly!

Typical of me I have interfered slightly with my regularity because I have just finished a 5 day fast! (a la Valter Longo Fasting Mimicking Diet) so that has obviously slowed me up a bit, fully expected - I’m hoping that normal services will be resumed shortly!

I really hope that you have managed to settle down to some kind of normality for you and thanks for taking the time to lend some credence to my postulations! - ooh, big words for me, the fast must’ve done me some good!

All the best

Elaine x

Oh no, 2nd dose of Pfizer and duplicate effects. I was prepared to accept the diarrhoea as possibly just coincidental to the jab, but not the second time. It was almost identical - started with old dense poo that turned into diarrhoea. It’s now day 7 post jab #2 and this morning was the worst ever. I don’t in anyway want to scare anyone. After all, my experience appears to be statistically miniscule compared to the majority of people. Of course, I’m a bit unusual too - having MS and a colostomy. So it’s not likely to happen similarly for others. Just enjoy the side effect of regular bowels if you get that. And hope that it lasts longer on dose #2 than with dose #1!!

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Yes, it’s too much information. It’s interesting though.
There’s a mechanism for reporting side effects and reactions to the vaccines and I’m certain bowel movements will be of interest.

Well I’ve had my 2nd appt through. it’s not for 2 weeks yet, so we’ll see. I’m fully expecting (selfishly hoping) for the same effect. :wink:
I also reported my findings on the yellow card scheme just because I thought it might be of interest - but I’m sure these vaccines must have to evolve constantly, it’s all very clever stuff, thankfully!
Elaine :slightly_smiling_face: