One in four people get Pfizer and AstraZeneca vaccine side effects

astrazeneca vaccine side effects, pfizer side effects
© Pier Paolo Todaro

New data from the UK’s vaccination programme suggests that one in four people get Pfizer and AstraZeneca vaccine side effects – with most peaking in the first 24 hours, then gone in two days

The study by King’s College London looked at the UK population, which is currently using mainly Pfizer and AstraZeneca. The data was drawn from 627,383 participants, who reported their reactions to vaccination between December and March.

Side effects are one of the key reasons that some remain nervous to get their first or even second dose. But in this new data, scientists look at how the vaccines have been working in the UK to understand how serious side effects are – they found that there were fewer side effects in the population than in the original clinical trials.

If you already had COVID, are the side effects worse?


Participants who had a confirmed case of COVID were three times more likely to have side effects in their whole body after Pfizer, than participants who did not have COVID-19 previously. People who had already experienced the virus were also more likely to have tenderness in their arm.

What are the real-world side effects of the COVID vaccine?

Only 25.4% of vaccinated people said they had side effects (that were not a physical pain at the injection point), while 66.2% said they had a local, injection arm related side effect.

More people reported a side effect after the first AstraZeneca dose than the Pfizer, while the most common side effect was headache. People who took Pfizer reported that the second dose gave them a headache more than the first dose. Overall, more people had a headache after the AstraZeneca first dose than the Pfizer first dose.

The second most common side effect was fatigue. According to the data, 8.4% and 14.4% of participants reported fatigue after first and second dose of Pfizer vaccine and 21.1% reported fatigue after their first dose of AstraZeneca.

Then, the most common local side effect was tenderness. Around 57.2% and 50.9% reported this effect after first and second dose of Pfizer vaccine, and 49.3% after first dose of AstraZeneca.

Which age group has the most side effects?

This research identifies that side effects were more common among people under 55 years of age and among women, which is different to who is most impacted by COVID itself. This is a situation that has not been widely discussed in the media, leading some to panic about their side effects.

‘Effects of the vaccine are usually mild’

Professor Tim Spector OBE, lead scientist on the ZOE COVID Symptom Study app and Professor of Genetic Epidemiology at King’s College London said: “The data should reassure many people that in the real world, after effects of the vaccine are usually mild and short-lived, especially in the over 50’s who are most at risk of the infection.

“The results also show up to 70% protection after 3 weeks following a single dose, which is fantastic news for the country, especially as more people have now had their second jabs.”


  1. I have multiple autoimmune diseases and witin about 1 hr of my 2nd Pfizer vaccine my whole immune system has gone crazy. It feels like all my autoimmune diseases have been turn on and I’m having a massive flare it’s been two weeks now majow daily headaches alday every day I have not had a break. When will this end 🙁

    • How long does your side effect last? I have gotten my first dose of Pfizer vaccine and from first hr I had numbness on my face, from the second day of my vaccine I had tingling in my feet at night. I am wondering if I want to get a second shot.

      • My son got his 2nd dose of pfizer and a couple hours later he said the bridge of his nose hurts and his face feels numb. Im wondering if we should go to urgent care. He’s 16.

    • Hi Allison
      I’ve had my both Pfizer and I’m immune suppressed and my 1st was ok but a week after my second shot I’ve been so sick with headaches,horrible taste in my mouth, dizziness so bad all day hopefully it will end soon .Talked to my Doctors not enough study with my medication so there just seeing how I go I haven’t felt this sick since I was first diagnosed with Crohns ..

  2. 4 family members had both doses of Astra-Zenica with no side effects other than slight ache in arm at site.
    Ages between 24 & 70.I
    4 family members had 1st dose of Pfizer with 3 suffering awful fatigue, headaches and limb stiffness. The 1 person who only had a Slight ache was a 24 year old, the unfortunate 3 were between 42 and 53. In my view, (with no proof) i believe Pfizer is better given to younger people who are more active. Astra-Zenica is better for those who are older and less active.

  3. Hello it’s been 3 days since my Pfizer 2nd shot all out of nowhere my right arm but more hand got so numb and felt like I had no right feeling and my arm and now it’s starting in my left arm and as well as my nose bleeding

  4. I am 77 years old, and relatively healthy. Had my first Pfizer sot on the 23 June, and have been constipated since then. My second shot is due on the 4th August – is this a normal period between the fist and second shot?

    Many thanks

  5. had first Pfizer vax early march and had 2nd dose.But I have suffered the most agonising one side of forehead nerve head pain since had first vax… I have multiple sclerosis and one symptom is I suffer optic neurotic in right eye from time to time. This head pain is like an extension of opticneuritus as frequently get both together and both on right side of head. no pain medication gives any relief at all! on telling my go I felt the new head pain was due to Pfizer vax he neither agreed disagreed, told me to take paracetemol…I am taking slow release morphine and liquid morphine for another disease….seems like whatever time I have left will be spent in constant head, eye pain and worsened cognitive abilities

  6. I had tinnitus before my Pfizer vaccination, it was mild + didn’t affect me very much. Since my 2nd vaccination the tinnitus is horrendous, headaches, dizziness, the noise is a screaming in my ear, it is driving me crazy + I am scared of falling due to the dizziness, I am 76yrs old which doesn’t help.

  7. Iam 60 yrs old and had the pfizer jab 3 weeks ago now i have bad head ache all day and both my arms have serious aching biceps why?

  8. I am 70 yrs old. On the 29 June 2021 had second shot of Pfizer. 2 weeks to the date I woke up unstable! facial muscle movements exaggerated! Uncontrolled twitching movements of left foot and left arm, continues today. Went to emergency, 6 hours later after a cat scan (C/T) and some blood work, the doctor said everything looks fine can’t see anything wrong with you. The next step will be a neurologist she said, so I’m waiting for them to call me for an appointment

  9. I am suffering with blurry eye vision and severe pain on the top of my legs and I have only had the first shot of Pfizer

  10. I got my first Pfizer vaccine and was very sick with fever and gastrointestinal pain for several days. I am now left with a very itchy and swollen lymph node proximal from my tricep and distally from my armpit on the opposite arm.

  11. I received my first Phizer vaccine on August 6,2021. Since then I have had a mild headache that comes and goes and numbness in my left hand and arm and now my right arm. I am afraid to get my second shot because I cannot afford to have worse headaches or other side effects than this.

  12. A day after my 2nd shot on same side as shot my jaw, ear and teeth on that side hurt so back Tylenol and ibuprofen are hardly touching it I’m sleeping on the heating pad on the back of my neck and ice pack on the side of my face hoping this goes away soon.

    • I also had severe nerve pain left side of head n face. after first injection of Pfizer in Augest 21.It had me in tears the second day and
      gradually eased off few days, but, no tablet, even Ibobrufen eased it off.
      I wrapped myself in a blanket and sat in armchair
      praying as I could not sleep.
      I am 82 yrs old and reasonably healthy.

    • I thought I was going dotty until I read this feed. I had my Pfizer booster two days ago yesterday I couldn’t move my head to one side and the pain in the base of my skull was excruciating! I’ve not slept for two nights as I couldn’t get me head comfortable. I was walking round with and ice pack at the back of my head at 4am in agony. At 5am I managed to prop myself up and drift into a sleep. I’ve woke with just a dull pain now I’m praying this is the end of two days pain I can’t for the life in me say if this was a reaction to the booster or something else but it was awful!

  13. Just had my 1st Pfizer vaccine on Saturday, been in bed ever since with chronic fatigue, left arm (where I got the shot) is heavy, numb and tingling. Inside my mouth feels weird and back of my throat, chest feels very heavy. Not sure I want 2nd vaccine now

  14. I received the first injection yesterday August 26 that evening my blood pressure sword to 187/98 for most of the night my blood pressure stayed in the critical Status I doubled my heart blood pressure medicine and I’ve drank so much water that I can’t even get any rest has anybody else experienced this my wife called the emergency room and they said that happens what a ridiculous answer thanks

    • yep, normal blood pressure 130/75 then sometime after second shot worst headache ever and bp of 178/108. This lasted 2-3 days. It came back again after a few weeks, same story/symptoms but add nausea. No temperature, swelling or any other symptoms. This subsided after 10 days… Hopefully, this is now gone for good – but I do not look forward to the booster shot… I am 50 odd years old, healthy, eat healthy, exercise multiple times per week. Hardly drink alcohol do not do any drugs nor on any medication.

  15. After the second and third injection, about 12 hrs later my joints ache and I wake up freezing in 90 degree weather. Have been tired and having a hard time sleeping since the first injection???

  16. Had first Pfizer, all good, but 10days later lower back went into muscle spasms and incredibly painful movement, numbness down left leg, arms now feeling like jello, been to chiro, doc, physio. No relief after 5days, hoping it gets better soon

  17. I had my first Pzifer at end of August. I had immediate strange feeling which I thought might be anxiety. Within 30 Seconds in obs room. had immediate severe whole body flushing Taken for obs in side room. BP. raised. About 5 events of very severe flushing Lasted 40 minutes in total and was allowed home in about. 1 hour Am anxious about whether I should get my 2nd Pziferat end September I am 84 years old

  18. I got my first Pfizer shot and everything seemed fine except for a bit of soreness in my arm. However, a week later I started getting tingling/ burning sensation and partial numbness in both my feet which was worse at night. Now I’m worried about getting the second shot

  19. Five weeks after my second shot I got a cold from hell it lasted about a week and a half I got all better and then I got sick again but basically the same thing and I’ve never been this sick before the vaccine so does anyone else struggle out there with a stuffy nose and runny nose bodyaches tired so we’re throat and coughing supposedly this is my immune response. Anyone else out there?

  20. Had my second pfizer yesterday. I am so very sick. My whole body hurts, especially my neck. The pain is worst pain I ever had. When will this stop?

  21. My 18 year old son had his second Pfizer vaccine 3 weeks ago. He is totally fatigued sleeps 18 hrs awake 6… previously before the vaccination it was Visa versa sleeping only 6hr. Been to walk in centre but still has no energy what so ever. Anyone else son/daughter felt like this?

    • Yes my daughter is 26 always tired now, can’t focus, can’t concentrate, I am so concerned as to what happened. She was completely healthy before the vaccine

  22. After getting the 2nd dose of the Pfizer vaccine, my left arm that I got the Pfizer vaccine in – keep pulsing at intervals throughout the day.
    Anyone has this happening to them as well? It is very discomforting the pulsing – you can actually see the flesh of my arm pulsing.

  23. I had my first Pfyzer in February.On the 3rd day my leg felt frozen.By the 5th day I developed large swellings on my ankle that copied themselves on to my other leg.They have now spread up my legs and arms.Some are as big as my hand and surrounded by fluid..My legs are twice their size.Im on my 4th Consultant and nobody knows what to do.They are now pressing on nerves and causing pain.I am so scared as they are still spreading.I cannot have the second vaccine and I dont want it. But I am just a mystery.Surely something can neutralise this.My immune system is obviously fighting this and losing.They are still coming in different places.

  24. 1 st shot arm was extremely sore next day . Bruise on injection site for 3 weeks . Now my heart raises and pauses . Left hands cold a lot and my throat feels like there’s something in the back that I can’t swallow which sometimes makes me cough. Scared to get second but it’s either that or I get fired.

  25. I’ve had a constant itch/rash on my arms and trunk which is keeping me awake every night since having the Pfizer vaccines in Jan and April. It is torture .I’m 77 so can’t risk getting Covid but extremely worried about having a booster. Should I try to get the AstraZeneca.

  26. I am 46 female .
    I Had my first pfizer shot
    That night i felt extreme pressure in my eyes and second day i started getting lymph behind my ear hurting and then shooting pain to my head, as well as bruising on my body
    It was a weeked so second day got worst… I took advil a baby asprin and a water pill.
    It went away for the day . However next day it came back . Is this normal??

  27. After getting Pfizer 2nd dose I get tingling burning numbness ad itching.,in my hands. I just had my booster will see what deveiops. Wakes me up cause the burning hurts so much. I use t-relief gel seems to help some. I get it on Amazon. Probably will help people who have this in their feet.

  28. My partner and me , had our Booster ( Pfizer) one week ago with on reaction , today we both have quite strong hip joint pain , is this normal to get a side effect after 1 week or is it just coincidence . i wonder.

  29. i have had booster of pfizer vaccine in right arm. 2/3 hours after left arm ached as though I had jab in that arm. into the evening neck and shoulders also sore as if I had slept in an awkward position , 1 week later left arm aches neck and shoulders still sore now right fore arm and hand aches . bad head aches and tired. I am 73 yrs old and usually in good health. no after effects after 1st and 2nd jabs but booster giving above symptons ,paracetamol does help for short time.

    • I’ve had my Pfizer booster I am male age 51. After having the booster my finger joints hurts like madness. Never suffer from this before plus my heart races …. Anyone has this side effect ?

  30. After 1 month of getting the 1st shot of Covieshelid. Astrazenca vaccine in India i started seeing cystic acne and pimples all over my body in moderate numbers.
    I also got to meet many others facing the similer situation. However no serious side effects are observed.

    Those getting pimple and acne in my proximity are covid servivors so yes i think that reactions for covisheild and astrazenca appear to be a bit more visible in these cases.

  31. I had the AshraZeneca in Feb and the 2nd in April, I was fine after the first but about a week after the 2nd, I had trouble breathing and was very tired, I fell on the pavement and was taken into hospital where they found 3 large blood clots which where affecting my heart. I have always been a very active person, I have a number of health problems but that has never stopped me before.
    I had the booster 2 weeks ago the Phizer I was fine for the first few days then the pain in my legs started it was the worst I have ever known. It was like bubbles going up and down, it was painful to touch my musles and trying to to lift my legs up was agony.
    I was awake all Sat night and it didn’t ease off until I found out, that it got a lot worse after taking the blood thinners that I have had to take since the last injection. The doctors where closed over Christmas so what else could I do but ease off the blood thinners.

    • Why on earth would you take the 2nd or 3rd after having horrendous side affects from the first. Should have been a warning to you. Not hey let’s go get another 2 doses. You should be looking after you’re health not being a Guinea pig injured by these unsafe injections

  32. I had the booster fsizor and a creeping sensation around the injection site that travelled over around my shoulder. It is now a month on and it has continued to creep over my back. It’s obviously my immune system reacting but has this happened to anyone else?

  33. After my first jab several days later i had lumps in both my arm pits which i had to have removed in hospital now serveral weeks later back in hospital a lump appears on my left shoulder hospital staff put bandage on it no two weeks later ive got a pump attached to my shoulder pumping out what eva it is ive got

  34. After I got my third Pyzer booster, I have a metallic taste in my mouth continuously since Jan 31, 2022! It’s horrible and most foods taste like metallic mush! I also have a body ache!
    I am is good health usually! Hope there is some way I can get my taste buds back?

  35. I had 2 astra zenica jabs was OK then had my booster which was pyzer as soon as I had it in my left arm I had numbness I my left shoulder blade with pins and needles for about 2 months then it moved to my right hand side rib cage and stomach for about the same time and now it has moved to my left arm bicept can’t explain what it is


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