Research says 12 weeks between AstraZeneca doses improves protection

astrazeneca doses, doses
© Mvg682

AstraZeneca dose efficiency holds at 76% in the three-month period between the first and second dose – suggesting that this time period is good for maximising protection

The UK currently stands at 108,000 deaths, with an average rate of 1,122 people dead this week. One of those individuals is 100-year-old Captain Tom Moore, who raised £33 million for NHS charities by walking laps in his garden.

However, inoculation plans are going ahead on schedule. It seems that the UK will meet the 15 February target to immunise the most vulnerable categories of people – despite the ongoing fears about the South African mutation, and the disparity in vaccine take-up for BAME communities across the country.

This research is the first to examine how a COVID vaccine works on transmission, alongside confirming that the UK approach to administering doses (12 weeks in between as opposed to 3 or 4) is supported by the outcome.

Further good news is that transmission is reduced by 67% in those who have been given the Oxford and AstraZeneca first dose. That’s a significant amount of reduction in positive tests, suggesting that the vaccine really is stopping COVID from jumping easily from person to person.

Recent debate over the intentions of AstraZeneca CEO and the Commission mean that this research revelation is inevitably politically charged, in dismissing French criticism about the UK’s decision to dose in three month periods as opposed to sooner.

Is it better to give the second dose of the vaccine after 12 weeks?

The short answer is yes.

The three month period 22 days after vaccination is when an individual maintains 76% protection from COVID. It takes 22 days for the immune system to build-in the protection offered by the vaccine, which is the explanation for why some people may still catch COVID after being injected. This is why social distancing measures remain strictly in place.

When the second dose is given after 3 months, this level of protection rises to 82.4%.

Professor Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial, and co-author, said that the new data “reassures us that people are protected from 22 days after a single dose of the vaccine.”

However, if the second dose of AstraZeneca vaccine is given less than six weeks after the first one, protection only rises to 54.9%.

Professor Pollard further commented: “These new data provide an important verification of the interim data that was used by more than 25 regulators including the MHRA and EMA to grant the vaccine emergency use authorisation.”


  1. Had jab sat ok till last night and today fell worse am 57 I have COPD enphazymia hope this flu like feeling goes quickly. Will it? I’m on oxygen machine too. Struggling to walk. But I try now I’m unwell don’t want to even try to exercise.

  2. I had my Astro vaccine on Feb 2nd. I was fine. Then it started, the falling, dizziness, headaches, slurred speech,
    it’s 26 days and was sent to hospital two days ago for TIAs. The forgot to do brain Doctor sending me to a different hospital.
    Have friends with same symptoms. No one had these with Pfizer vax. Italy and Spain stopping Astroveneca for over 50’s. Strange this is not on OUR news. I only had the vax to help others.

  3. I had the 1st vaccine friday very sore arm felt sick all day sat then felt hot followed by shivering and felt unwell today sunday feeling fine no sickness or chilis.

    • Everybody I know has had side effects. When I was shivering in bed from chills after having it done, I was believing the conspiracy theories.

  4. Same as Christine Malcolm, took AZ Oxxford 1st dose on Fri 5pm, Sat some lethargy and tiredness and a bit of a sore arm and Sun felt OK.

  5. Had Oxford AZ on 28 feb for 48 hrs after had aches and night sweats. Then came the fatigue and feeling anxiety and 9 days in stiil experiencing fatigue and anxiety.

  6. Had my first dose of the AZ vaccine 5th Feb. 24 hrs later a massive aching and fatigue started. It’s now 5 weeks later. Sitting in the house, doing little, I feel ok. If I do go a walk I can do it. Afterwards, a very severe fatigue overtakes me. Real aches. These continue unless I completely rest for about two hours, after which the aches subside. I had a negative Covid result.

  7. I had a headache that took a week to shake off. It’s now a month since my first jab and my arm is still painful a lot of the time. Anyone else had this experience?

  8. Me too 6days ago had my first Az vaccine felt so ill
    Sickness I felt like I had gastroenteritis like I had before felt bad Anxiety still now really worrying about second jab too.

  9. I had my jab on Saturday 20th March. Felt fine all day. The next day felt nauseous and extremely fatigued. Today I had really bad stomach cramps, upset stomach and feel sick. Oh well, tomorrow’s another day!

  10. Had my astra vaccine on monday, was up all night, tuesday i was in pain all over my body, temp sky high, dizzy, head ache, fast heart rate , wednesday i thought i was going to die, i felt so weak, thursday, symptoms easing, todays friday, much better, arm still sore, but wow, never felt that ill in my life, but, will have second dose, better this than covid guys…

  11. I had my Astra Zenica jab on March the 18th went down with a bang nausea high temperature put me in bed for two to 3 days

    • Mary this is Lenard. I just read your post and I am experiencing the same effects. I am scared to take the second. I am suffering from anxiety—just this nervous feeling which I never had before. So I am with you.

  12. Oxford vaccine in February still got sweet sickly smell, also. Sweats and anxiety, how much longer will i feel like this. The second vaccine will be soon and im feeling scared

  13. Took the AstraZeneca vac in the 9th of March. For approx 48hrs had muscle aches and pains with fever. Then came the anxiety with my heart beat racing. my pressure was also unstable. Had to go to the hospital. I am home on sick leave. Today is the 5th of April and I am still feeling anxious. Is this normal? How long is this going to last. Does anyone have these effects?

  14. Had Astra Zeneca vac 4-2-21
    Had bad pains from second day not flu like.
    headache pains in face, nausea, joint pains in back and foot shoulder arm, wrist hand pins and needles. And very tired and strange I am due the second one on 23rd April
    But as I still have pain in the muscle where I was vaccinated and my shoulder and neck is still bad not sure I’ll have it as I don’t wish to be left even worse off. Anyone else left with these side effects after nearly 3 months.

    • Hi Katrina
      I’m 72 and I had the 1st jab of AZ on 26th Jan and had pain for 8 weeks in the site arm muscle. Also ache and pain in my neck, shoulder and base of skull starting 2 weeks after the jab. Still got these after about 11 weeks and am having physio with some small relief so far. Just had 2nd jab and waiting for any further effects to appear, hopefully none. Please post to say how you are getting on.

      • I had my first jab of AZ on 25th Jan, and was absolutely fine, no side affects, only feeling a little tired the next day in the afternoon. Had my second jab 9th April, at 10.25, by midday I Had developed really bad shivers, couldn’t hold my phone, ached in every bone in my body, took 2 paracetamol went to bed, I was not right for three days,. I swear the way she put the needle in me, it was like stabbing me. Different to the first jab. I am 73.

  15. Had first jab on the 4th of April.
    After 4 days I began to get headaches above left eye. After 6 days the left hand side of my forehead started to go numb and painful.Still no improvement.Phoned 111 and they said it could pass After 2 weeks and prescribed the usual painkillers which do nothing.

  16. Had AstraZeneca 1st jab on 6th April, all ok, 8th April some numbness on right side face, 13th April still have it, anyone else get this.

  17. I just had the AZ here in Calgary – just barely old enough to get it! Absolutely zero side effects except a bit of hot skin around my neck and chest, interestingly. I promise I will post again if anything changes!

  18. Had AZ on Friday the 16/421. Woke in the night with very bad shaking (shivering) lasted about 20 minutes. Eventually got back to sleep and then started again. Also felt nauseous and did vomit a few timed. Again lasted about 20-30 minutes. Sat slept most of the day and didn’t eat much. Sunday feel much better although slight pains in abdomen ( could be from the shaking). Just hope second dose has non side effects.

  19. Hi had AstraZeneca 6 weeks ago and still have an aching arm. I had a bad head for 8 days after it and still getting headaches now and again and feeling really tired all the time. Second vaccine on 22nd May and dreading it

  20. Just had second AstraZeneca 6.5 hours ago. Probably speaking too soon but feel fine.
    First jab within 4 hours had horrible chills, shakes, fever, headache, nausea, headache, sore arm and tiredness. Following day just left feeling tired and headache. 3rd day gone.
    I have my fingers crossed.

  21. I had the AZ on 12 March 2021 – had a very sore arm for 4-6 weeks – 9 weeks on my arm is a bit better but still sore (with neck and head pain on the same side) when I swim or do any weight-bearing exercise, even yoga. I’m tired of it now and won’t be getting the 2nd one until it is fully healed. I’m only 44 and fit and healthy so the protection i’ve got is good enough for now.

  22. I am female aged 67 with Heart disease. and rare Autoimmune diseases. After my first injection I felt a tired for a week after the third week I noticed a huge nodular painful lump on the inside of my thigh it was the size of two grapes and painful.I had not injured myself. I decided to gently massage it within two days the lump had gone leaving a palm sized black and blue area.
    I had my second injection 2 weeks ago at the moment. all I have is a painful arm and intermittent severe headache that comes and goes.


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