Occurence of Fever after #MSCOVID19 vaccine


I thought I would have a look to see what the information says about fever after the Jab. This may be important to you as temperature can transiently worsen some peoples signs if there are demyelinated lesions. This can mean a transient increase in signs due to Uthoffs phenomenon

I thought I could try and decipher what happens from the papers, but the best source of data if from the regulatory approval rather than the papers. The FDA is a good source of information

In the UK, we currently have the Pfizer, Moderna and Astrazeneca vaccines approved, in the EU there is the Pfizer, Moderna amd Astrazeneca (although they dont seem to be using in it in older people) vaccine and in the US there is the Pfizer/BioNTech, Moderna and Janssen vaccines approved.

As I have said a number of times the Oxford trials have been a bit of a “dogs breakfast” in their application as they were doing studies without access to the vaccine meaning the dose and the dose intervals were all over the place. I was surprised to see that in the regulatory documents from the MHRA (UK) and EMA (EU) there is not much data given that thousands of people have been treated in the trials. There is no data for fever after the first and second dose, although this can be found in a study of very few people. It simply says the occurrence of fever was 7.9%. One images this was based on thousands of points. But it is is not clear.

This document lacks some clarity that can be found in the FDA documents and makes you think this is one of the reasons that the Astrazeneca vaccine has not yet been approved in the USA and as time is passing you wonder whether it will ever be approved and used in the USA. I believe a trial is being done and apparently it may be finshed in a few weeks so. But it is behind the curve and maybe it they don’t want it they can send some over here, or the EU for the Whipper snappers or maybe to a country that needs it:-).

It is hard to compare the different agents, they were do on differnt people, different age groups and are reported in different ways. Generally older people do not react as badly as the younger people so for the US readers, I have fished out the data relating to the development of fever, equal to or more than 38 degrees centigrade, in old money that is 100 degrees Fahrenheit. I have grouped the old together and class severe fever above 39 degrees centrigrade

The occurrence of fever is in bold

There are many similarities. It is clear from the RNA vaccines that Fever is more common on the second dose, there is only a small study reported that suggests for the Astrazeneca vaccine the reactions may be less second time round.

As some people have said the effects of vaccine fever are going to be more transient than COVID-19 fever. Fever from COVID-19 occurs in about 50% of mild and asymptomatic individuals according to the European CDC. Therefore, the vaccine is better than getting COVID-19.

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  • Somehow I feel like cumulative chance of side effects would be a more appropriate number than the current average per dose for the multi dose vaccines

  • My mother had the Sinopharm last week (couldn’t source anything else for her) and developed a sever fever and pneumonia the next day.

  • I’m glad to see this article.
    The Covid jab left me incapacitated for 12 hours. I had no sense of a fever as such i.e temperature and sweating but my MS symptoms went through the roof, I literally could not move.
    I had my jab at eight in the morning and by six in the evening I was done for. That night was spent in a downstairs bedroom as I couldn’t get upstairs, A bucket next to the bed doubled as a toilet.
    The following morning was difficult but by mid afternoon I was starting to regain function. It’s not the first time this has happened following a vaccination although the annual flu jab it’s nothing like as bad.

  • I was one of those who experienced fever after the first dose of the AstraZenica Covid vaccine. It felt like the worst flu possible. Also very upset gut. I spent two ghastly days in bed but was poorly for a week. It did make my MS worse. I thought this happened as I am 74 and have had MS for more than 50 years. I will not have the second dose as I can’t go through that ordeal again. I see that in some countries the vaccine is not being given to those with MS or the over 65s as there is too little data saying it is safe. Whenever I have tried to tell of my experience I have been slammed down. Facebook removed my post saying this after 5 minutes. I do not believe what I am saying is disinformation or misinformation. I am in favour of the population being vaccinated to contain the Covid virus. But I think there are some people such as me who should not get the vaccine.

    • Also ask if you have been infected before. However, how to you predict which people will have side effects and therefore you can’t say people should have it

  • Hello,

    I had Oxford Astrazeneca 10 days ago.

    Pleased to say that I did not have a fever but I felt rubbish for the next couple of days. Fatigue and the idea of doing anything remotely strenuous was impossible were the only problems. I did not have an increase in temperature which I would notice because I suffer from Uhthoff’s syndrome.

    Speaking to other people who do not have MS they have had a similar reaction.

    • I asked this on an earlier blog a few weeks ago, but there were no replies.
      I felt rough for several days following the AstraZeneca vaccine, but then alarmingly
      my “MS legs” returned with a vengeance the following week & lasted for roughly a week before returning to my normal. It worried me so much that I rang my MS nurse to ask if she was aware of anyone else with similar symptoms, but she hadn’t. She thought the MS symptoms were probably a reaction to the feeling rough along with immune response to vaccine. It looks as if she was right.

      • You are probably a MS pioneer and got the vaccine early….so we dont have a feel for peoples experience but the feedback we have had from our initial group of people has been the vaccine has been tolerated. I am guessing people on DMT may be younger and less disabled than some others, we still have to offer vaccines to many people

  • I posted here recently about this as I had a temp of 38 within 8 hours of the A-Z (plus other symptoms) and I had a worsening of my MS symptoms (fatigue and leg weakness) for a week afterwards. Remain very pleased to have had the vaccine and will certainly get the second one.

    Listened to the Kings College Hospital/Zoe webinair yesterday and they said that people with MS have been in the trials and we know that people over 65 have been, as well as many millions vaccinated in the Uk with evidence of effectiveness.

    They also had some data on side effects from vaccination that they have been collecting from self-reports and as above (mousedoctor) it looks as though people who had the A-Z vaccine had fewer side effects after the second dose so I will remain hopeful.

    Judy, sorry you had such a bad time but maybe next time will be better and you will get increased protection after the second vaccine and hopefully avoid getting covid which could be worse.

    I have not submitted a yellow card report about my side effects as they are listed as 1:10, it’s just the temporary effect on my MS that was different.

    • Yes temps of 38 are in the mild/moderate. The severe above is over 39 degrees C. One of my friends has a temp they say of 42C, which very high. Luckily it responded to paracetemol

      • Europe has blocked the most recent delivery of AZ vaccine to Australia. Given the disparity in infection rates between continents, most Australian media outlets are stating it’s reasonable and understandable. Nevertheless, we need to start our vaccination campaign. We don’t have enough of the Pfizer vaccine to go around. Hopefully CSL will start making the AZ vaccine soon. I’ll be interested to read more about how pwMS fair after receiving their immunisation. My wife is yet to receive her’s. She is nervous it will worsen her symptoms. As I said to her, you got through your alemtuzumab treatment, so this should be a walk in the park. I’ll be getting mine the moment I’m eligible. I’m starting to fall apart mentally working from home, not going out, and having minimal contact with people (all self enforced to ensure I don’t bring anything into our house and put her at risk). I’m sure many people in the UK are feeling the same. Stay safe everyone and please get vaccinated if you can.

          • So I hear but I believe that is 12 months or more away. CSL has started manufacture of the AZ vaccine and we are underway with our campaign. TGA approved AZ vaccine for over 65’s (a surprise to me given other regulatory agency findings). A sensible decision given our unique position and the data showing a reduction in severity of symptoms (a factor the media have overlooked in their reporting of the AZ vaccine). Australia is now haggling over costs and whether clinics are being paid enough to administer the vaccination. Let’s hope this issue is addressed promptly so we can ramp up our vaccination efforts. Hoping to see friends and family in the UK soon. Wishing everyone the best and hoping for a positive outcome for all.

      • Anything that could be gleaned from the webinar Sue/MD about the extent to which PwMS response to the vaccines is blunted?

        • I went to the seminar from ZOE….they boasted 20,000 people attended and 4000 questions but they answered a few with stuff I already know. It is online if you want to reliive it. They did three slides in an hour (that is usually about 2-3minutes info)…I may have missed it if they said something new….Phone rang to wish me happy birthday and I lost the will to go back. They are doing a study called OCTAVE…led from Glasgow although its an oxford study in the video.a I believe, but they are not really going to focus on MS….I asked how many people with MS have had Uhthoffs phenomenon…No response.

          • Thanks for the reply.
            Your persuasive sales pitch has persuaded me… not to bother!
            Belated birthday wishes – hope you’re enjoying a celebratory weekend of sorts.

    • We have a similar “yellow card”reporting system in Australia but most people don’t know about it. Doctors are too busy to report adverse events. Gotta wonder how many drug related events go unreported every year. I’d urge you to report it. The more data we have, the better we can evaluate the risks and benefits

  • Thanks. But I can’t face all that again. I don’t really need extra protection as I now never go out.

  • I must be one of the unlucky 7.2%. Will not risk second dose where the risk of fever is 16.3%! In some countries I would not have been given the Covid vaccine as too old and unwell.

  • I honestly feel due to the Astra Zeneca jab I had two weeks ago my ms has flared up. I’ve been wiped out, in bed, tingly spine, going to the loo in the middle of the night. It’s important to gather pwMS experiences and report them. I’m hoping it subsides. I think it slowly is. Just v hard to know if it’s a relapse or a vaccine induced flare up.
    Thanks for the honest blog post. I sometimes feel it’s all yes yes yes the vaccines are great don’t worry, get your vaccine soon. I would still get it but I’d like to know why I’m feeling the way I am too. There will be anomalies I suppose but good to gather stories.

  • I am 64, have SPMS and am on no DMTs. Had Covid almost a year ago and had my first Astra Zeneca vaccine a few weeks ago. Had it in the early afternoon and my hands began to feel cold later. Went to bed at night but woke after about an hour feeling hot, with pain in both legs below the knee and heart racing. Hands still felt cold. Got up and could hardly walk and had lost much of the sight in my left eye (Optic Neuritis diagnosed about forty years ago). Awake most of the night but had a few hours sleep.

    Was surprised to find that conditions had returned to normal when I woke. Could walk and see again, as before. Sense of taste took longer – good coffee tasted like instant for few days.

    • Thanks for the info…this sounds like classic Uthoffs. Neurologists used to put people in hot baths so that this woud show itself. Glad to hear that you recovered. With Covid the effect would be probably longer.

      • I find it disturbing people not wanting the second dose of the vaccine because of the side effects. I know people that have passed away from COVID-19. Also I have friends that have been gravely ill with it. The majority of people that had the Astra Zeneca were fine after a couple of days. The same with the Pfizer. A small price to pay when the alternative can be fatal. A temperature normally brings on more MS symptoms. So imagine how bad things could get with an uncontrollable temperature. Those most affected by the vaccine in my circle were those with no pre existing illness. I’ve had MS for decades and had a sore arm for a day and tiredness. It is different for everyone, but it’s Russian roulette as to the outcome of COVID infection. Just think whilst patients are blocking beds due to the pandemic none of us gets the MS treatment we need.

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