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There are 105 comments on COVID Booster Shots: Everything You Need to Know

  1. GOOD INFO. I’m wondering how soon after after receiving the booster does peak immunity occur? Is it several weeks, as with the first shots, or does it happen more quickly?

    1. I want to know please how many weeks I have to wait , whether it is 2 or 3 weeks, before my 3rd booster shot fully takes effect. I am having it this coming Sunday, September 26th.

  2. There is no place that says if you had covid last July and then six months later got two doses of the Moderna vaccine do you need a third shot or booster.

    1. I had breakthrough covid. After my 2 vaccines. I cant find info anywhere info on if a booster is needed or not in this situation.
      Thank you for this service. And info.

        1. If you get a second booster shot how long will it take to become effective

          What happens if you get your second booster shot the day after being exposed to the virus

    2. I was positive for covid 9 days ago and my job is giving the booster shots tomorrow witch will be my tenth day of having COVID so can I still get the booster shot

  3. This is the best and most informative information I have read for days about the booster and the vaccine! Thank you – after reading this I feel a bit more encouraged that those of us who are vaccinated will be doing well in the hard months ahead. Thank you to science and medicine !!

    1. Car molested vaccination in January as a health care worker. Just finished with Covid. Do I also need a booster.

      My wife finished vaccination in may. Got covid more likely from me. Worse symptoms too. Does she need a booster

  4. In order to get an effective immune response people who are immunocompromised need to get 3 doses as part of their primary vaccination series.
    After 6 months do they still need a fourth dose as a booster?

  5. I received my Pfizer booster and I’m anxious to hear about the Pfizer study as to what is the expected level of immunity percentages after the booster for infection/severe complications/death/break through infections, etc.. Can someone suggest where I might best find this info?
    I am also hoping to see a response to Paul’s question above as to when the expected peak immunity is reached after the booster.

    1. Just a sample of one, but I had a very strong reaction to the second dose. I was out flat the first day and it wasn’t until day 4 that I could function normally again.

      I had a 3rd dose a couple of days ago (6 months after dose #2). The evening of the shot my arm hurt, like it might from a flu shot. The next day I felt a little icky, as if I had had too much to drink the night before and then slept too little. I went about my day but as an afterthought checked my temp that evening – 99.8. Today I feel pretty much normal. So, bottom line, I did experience a reaction but nowhere near what I did the first time around.

      Apparently I’m officially considered immunocompromised because of strong chemo I received a few years ago but I don’t think my system reacts differently from the norm, I think I was just in the unlucky 1% that gets really, really sick from the vaccine. Still better than Covid!

      1. I also had a bad reaction to the Pzifer 2nd shot. I had the Virus in December and got the shots in May. I’m petrified to get the Booster. I was so sick for 6 days and one step from going to the emergency room.
        On the 5th or 6th night I broke out in hives all over my body and they were horrendous, but within the next day I started to recover. Should I get the booster or could it make more even more sick or kill me. Hives are dangerous so they could kill me.

      2. Same with me I had chemo in 2016 I had very bad reaction to my second moderna vaccine was admitted to the ER twice afterwards. I’m debating on my booster vaccine.

    2. I got the booster 8/23. I’m immunocompromised. The 2nd dose, I was slightly tired and swollen at injection site and then I got a lump under my arm that hurt, but subsided after taking Ibuprofen. For the additional dose, I felt very icky. I was tired, but couldn’t sleep and never got a fever (I’m usually @ 97.0 and I got up to 98.1. I was feeling slightly nauseous. So, technically, it was a little worse than first time around (different), but still mild.

    3. I got terribly sick the night of my 2nd dosage and all next day. I had a fever of 101.5 and had to take Tylenol to get it down. When I got my 3rd shot, my booster, I had no problems at all, not even a sore arm. I was also told this would be the case by the nurse who administered my shot. She said that most people weren’t having reactions, or if so, very bad reactions.

    1. I have the exact same question. I did not see a response to your question as to when can you get a booster if after being vaccinated you got the Delta Covid. Thank you.

    2. I was vaccinated in March tested positive for Covid mid-September I am 71 years old did not have a bad case but I am also wondering if and when I can get the booster??

    3. I have the same question. Vaccinated with Pfizer, second dose in Feb 2021. Breakthrough Covid about 30 days ago. When can I get booster. When can I get flu vaccine?

  6. I received the Moderna first in December 2020 and the second vaccine Moderna in January 2021 I am a healthcare worker and just received my booster ….however when I return to the same hospital to get the booster it wasn’t until she was getting ready to give me the vaccine that she said and showed me OK here is the Pfizer 0.3 …. I told her that I got to previous Moderma and was it OK to mix with the booster ….they gave me a Pfizer booster… I know that the CDC has not recommended that but I was told by the hospital that they’re both MNRA and that it would be fine…Can you tell me if this is OK since on my vaccine card I now have two Moderna and one Pfizer booster …. And going forward in the years to come should I just continue to get Moderna? Thank you

    1. I have read, at least twice (not positive, but think one was on CDC site) that mixing Pfizer and Moderna can actually increase the level of protection. It’s the same science– I can’t imagine that one would be harmed by another brand.


    1. I was wondering the same thing about mixing the Pfizer and Moderna. I got the Pfizer originally and today got the Pfizer booster, but was very interested in mixing them. I chickened out. I wasn’t aware of the “original antigenic sin” concept. That is interesting and makes sense.

      I got an antibody test yesterday (finger prick blood draw) at CVS to see what it said. I had gotten one before I was vaccinated and had no antibodies then. The test was 38.00 out of pocket. It told me that I definitely had no antibodies from the past three months IGM section and there was the slightest faint red line in the IGG section which could barely be seen that means I had antibodies at one point. My second vaccine date for Pfizer was 3/6/21, almost 7 months ago. With that data, I decided to get another antibody test this morning from Lab Corp for 10.00 out of pocket (insurance covers the rest). I made the appointment online. This test is a different type and will tell me a percentage or number range specifically. I’m very curious to what it says. I will be doing another one from Lab Corp in about 6 weeks to see if there is a big change. I also want my family members who got Moderna to get the labcorp test as an experiment as I have a hunch that they will show more antibodies based on the findings that the Pfizer vaccine is now only 39% effective and the Moderna is 76%. I drove four hours out of my way to get the Pfizer because of the 3% difference, but I regret that now. One thing that I learned from reading this article was that the T cell reaction is another very important measure and to not go by antibody levels alone. I just decided to do a personal study individually since I know that none of us have had Covid. I get tested weekly and the others are hermits.

  8. If you have an autoimmune disease are you more likely to get the Delta virus than someone with a good immune system? Will persons with an autoimmune disease be
    listed as a greater risk and be vaccinated sooner than those without?

  9. Thanks for the informative article.

    As noted, immunocompromised people, such as me, who were vaccinated with the J&J vaccine are left completely in the lurch. We cannot get a booster shot of any of the vaccines. In my case, I was on immunosuppression when I got the J&J vaccine. Three months later I got a blood test to see if I had any COVID antibodies — and I had none. Effectively I’m unvaccinated. My rheumatologist suggests I start all over by getting a series of one of the mRNA vaccines because I am off immunosuppression for now. But, no one is willing to vaccine me with one of the mRNA vaccines, leaving me wide open to COVID infection. I consider this a serious system failure of the FDA and CDC. It certainly is not patient centered. Suggestions appreciated!
    (BTW, recent evidence, not conclusive, is that Moderna will be better for immunocompromised individuals than Pfizer.)

    1. If you are considered immunocompromised, you can get them now. Consult your doctor. It’s not considered a booster for immunocompromised, it’s just an additional dosage. If you are not considered immunocompromised, then you’ll have to wait until it’s your time for the booster shot (8 months after 2nd dose of the initial series).

  10. I can’t seem to find any info about how soon the Booster actually “boosts” a vaccinated person’s immunity back to where it needs to be after 8 months. Will we need to wait weeks like we did with the 2 shots?

    1. I had my booster shot yesterday, & my second dose of sinovac 12 September 2021? 1 am 37 years old
      Gap between pfizer & sinovac is 4 months, is there any problem? Please guide

  11. I had my 3rd shot of Moderna Sept 6, 2021 and tested positive for covid Sept 14th. Had been to Dr on 13th for allergy symptoms. Was given steroid shot and Claritin. Next day realized food had no taste and went for test. Doing fine and never really felt bad. Guess 3 shots helped. I am 82 female

  12. My (Canadian) husband received AstraZeneca as his 1st shot. After the appropriate time internal, he received Moderna as his 2nd shot. In the eyes of the CDC he is not fully vaccinated. Will a Moderna booster render him fully vaccinated? Surely he won’t be considered unvaccinated forever….? How does one rectify a “mixed vaccine” scenario to enable international travel to those countries who don’t recognize it?

  13. I received a phizer vaccination. the first shot I had adverse effects and chose not to take the second shot will I qualify for a booster ? it has been over one year since I was vaccinated. What should I do?

  14. I am 70 years old, with high blood pressure and overweight. Ive had two doses of Moderna, the last on 2-1-2021. Am i considered immune compromised, and should i get the Phizer booster or wait for the Moderna when it becomes available. Thanks for the great article.

  15. Without reading every single piece of information, are the covid Pfizer booster shots activating your immune immediately thus bringing it back to 95%+

  16. Are there any reasons that would prevent me from receiving the Booster?
    E.g. if i received a Flu shot and Cortisone injections a week before my scheduled Booster?

  17. What’s the Point of asking questions if no one will respond with an Answer! Many of these questions are Valid and many are duplicates…but no Answer! What’s up with that??????

  18. 2021-03-24 Pfizer-BioNTech [ Tozinameran 0.3 mL ] – mild ache for two days at injection site

    2021-04-14 Pfizer-BioNTech [ Tozinameran 0.3 mL ] – mild chill awaken in early morning after

    2021-09-28 Moderna [ mRNA-1273 0.25 mL ] – no symptom yet since jab at 0056 GMT

    Moderna vaccine booster dosage reduced due to government expert health committee that reviewed the dosing for the Moderna vaccine used for boosting and recommended that 50mcg of the Moderna vaccine be used for boosting given evidence that a 50mcg dosage is sufficient to boost immune response significantly.

    by male age 60 ectomorph 48 to 50 kg 1.68m

  19. I’m so glad I was able to find someone else asking the question. I got vaccinated at end of January. I got a breakthrough case of Covid end of July, which was 6 months after receiving vaccine. I’m a health care worker and want to know if I should get the booster and if so when. I didn’t see the response of the other person asking same question.

  20. I received the Pfizer booster on Monday. I did not have any reactions to the fist two. I am so sick! Fever, body aches, chills, sweating profusely and diarrhea, I couldn’t go to work again today. When will I feel better?

  21. How long after getting booster of Moderna will I get full immunity? I have chronic fatigue and heart disease and feel tired most of the time. Will this booster shot make me more confident in not getting Covid. Do you think it would be ok to substitute teach young kids in the schools? Thanx, I’m tired of staying home, but don’t want to take a big chance on Covid?

  22. I am needing to know how long I need to wait after having covid and receiving the monoclonal treatment before I can get the 3rd shot or booster? I do have type 1 dm and also work in a medical facility.

    1. I have the same question. I had a breakthrough infection about 30 days ago. I am 72 with type 2 DM, HTN, and hypercholesterolemia. Pfizer vaccinated, last dose Feb 2021. When can I get a booster?

  23. I am not a conspiracy theory person. However…
    1. I had heard that the COVID Vaccine Booster destroys the Immune system (wbc production) over time, especially in older patients (> 60’s) with immune compromised and co-morbid disorders. I do not know if this with one or all of the COVID Boosters.
    2. I have heard that most of the high-level people in the Government / Politian’s have not gotten the COVID Vaccines nor the Boosters.
    I am very concerned about what is true vs. fiction. Some Vaccines have DNA, or RNA and Protein Spikes have been added. Also Scientist do not know the “long term effects” of the Protein Spikes or Vaccines.

  24. I had my Moderna Booster shot Feb 18,,,,,,,SO Oct 18 it will be 8 months. Now what? Are you going to need a shot every year? Or would it be good to get a test for antibodies?

  25. My Mum is having her 3rd jab this week. We are going on a cruise next week, would the test we do before boarding show she has Covid because of the third jab only being a week ago please?

  26. I’m a Type 1 diabetic and since receiving my Pfizer booster I’ve had blood glucose readings reach 400 and above requiring at least twice the amount of insulin injections than normal. As of this writing it’s been 3 weeks since my booster injection and my glucose readings are not back to normal. Prior to my booster shot I didn’t read or hear anything regarding this type of reaction. I strongly suggest that diabetics contact their endocrinologists regarding this issue.

  27. Hello,

    I’m a 30 year old female that is slightly over weight. I got my second dose of Pfizer in February and work in the administration side of healthcare (no patients, but in hospital). Do I need the booster or are my levels from my first set still sufficient?

  28. “Everything you need to know about the Covid Booster” but evidently no one needs to know or wants to know how long it takes for the third shot to become effective—if ever. I would think that would be one of the most important things to know. But you won’t find the answer anywhere on the web. Odd that.

  29. How about NOT calling your article ‘everything you need to know’ when it’s not everything I need to know? My question, which is REALLY obvious and REALLY important, is how long does it take after the booster shot for maximum immunity to occur. Seriously, guys, you REALLY didn’t think that was important?

  30. I received Moderna jabs #1 and #2, both of which gave me a headache and caused fatigue. I received my Moderna booster about ten days ago. Given what I read, I was expecting the next day to be similar to my first and second experiences. However, no symptoms of any type. Is that normal? I wondered if the dose was too low or if it exited my arm when the needle was withdrawn.

  31. I have just recieved my pfizer booster (0.3 ml) the dr said that I will need another booster in 28 days. I have never heard of a booster booster. Is this correct? I had my 2nd Astra Zeneca six months ago. I live in Kenya

  32. I had the booster and had side effects for almost 14 days. First 5 days I had a fever. body aches and
    slept around the clock. Then I was tired and slept most of the time. Is this unusual. The first 2 shots
    I had no side effects at all,
    1st shot 3-19-21
    2nd shot 4-25-21
    3rd shot 11-16-21

  33. 1) How fast do the T Cells and the B Cells decline.

    2) Isn’t that the most important question since anti bodies are SUPPOSED to wane as the other 2 immune defense mechanisms build up?

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