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COVID third shot
4 Posts


I am a breast cancer patient in BC, and finished chemotherapy in January 2021. I am now on hormone therapy (letrozole). I got invitation for the third COVID dose. Did anyone already get it? And any experiences/ side effects?

Thank you.

25 Replies

@NanaY I am in BC too and got the invite also. Haven't been for the third vaccine yet. Hopefully soon.

56 Posts

I had the third shot this Friday. Sore arm as before but also felt like I had flue symptoms for a night and day, then everything ok. They are recommending getting Moderna for third shot in BC if you have had first two in Pfizer because they feel mixing give you more protection.

498 Posts


just had my 3rd Pfizer on friday…..and nothing!

wish I'd known about the mix-match benefits @LGS


#fullyvaxxed #covid #bestprotectionisavaccine

329 Posts
LGS‍ and supersu‍ , I’m getting my third shot this Friday. I am in Ontario, and had Pfizer for the first two. But my pharmacist specifically told me to stick with Pfizer, and NOT get Moderna for the third one! This is obviously an evolving science!
57 Posts

Got my third shot of Pfizer last week; sore arm at injection site for a few days but no other side effects.

Ron 27
23 Posts

I have also just received my third Pfizer shot with just a slightly sore arm for a couple of days. I'm in B.C. and the nurse initially wanted to give me modera but had no issue when I told her to make it the Pfizer; both are available. All my medical team have said don't mix. I trust my logic and my medical team over the B.C. government's recommendation any day.

I got my third shot yesterday. Moderna - same as the last two shots. I am in BC. They were only offering Moderna for the 3rd shot at the clinic I was at. Sore arm is the only side effect so far.

94 Posts

Hello NanaY, Yes I got my third shot. I had Phizer for my first two doses and Moderna for the third. Felt a bit flu like for the 1st 24 hours after but that was all.

130 Posts

@NanaY I am in BC and also received an invite. I had my third vaccine on Friday. The first two were Moderna and this third one was as well.

Friday afternoon, I was a bit tired and had a light headache. I woke up in the middle of the night, frozen and teeth chattering. I had a bad bad headache all day Saturday and was fatigued Saturday and Sunday. Monday I was just fine. My arm was sore for the first two vaccines, but not so much with the third.

130 Posts

@LGS the nurse told me that they gave Moderna as a third vaccine in every case. I specifically asked about the mix and match benefits and she said that it's only when you have Pfizer for the first two.

Great discussion. Turns out that there is a lot of flying by the seat of the pants here. Nothing quite like breaking new ground while trying to confront the reality of a pandemic. The situation is evolving as the military likes to say. The research is just starting to be reported in the scientific journals. https://www.medrxiv.org/content/10.1101/2021.10.10.21264827v1 Note this is a preprint and NOT peer reviewed.

My own experience here in BC was similar to many reported here. My first two were Pfizer and the third was Moderna. Hetrologous application was my desire as I had seen some previous research (which I can't find now) that suggested that a third Pfizer booster didn't do much. I started off with a similar sore arm to the two previous shots but then intense fatigue hit and I had a ten hour “nap” on Monday night after the shot. Tuesday was filled with “flu-like symptoms” characterized by lowgrade fever, achy joints, restlessness, loss of appetite and just generally feeling shitty. I ran at about 70% yesterday. Today I feel like 120%. Dunno if it is just the rebound from feeling crappy, having the joy of the additional protection, or just my general “joie de vive” returning.

As I heard in a podcast earlier today “Carpe Diem - seize the day before it seizes you.”


4 Posts

Had my 3rd shot last week ( Pfizer) feel great..sore arm for a couple of days ( anal cancer free 5 ½ months )

Hello All,

I checked with my colleagues in our Policy department and wanted to share the following with you all:

Currently there is no recommendation on which mRNA vaccine is the preferred vaccine for an additional dose. Our CCS recommendation is for individuals to talk to their healthcare team about which of the approved vaccines is right for you, and to determine the best timing of a possible additional dose based on your unique circumstance.

I hope your healthcare providers support you in making the right decision for you,


13 Posts

I had my third shot two weeks ago and was fine the first day, the second day fever, chills, sore arm and swollen, third Moderna shot. The other side affects went away by day 3 except for the red swollen arm which lasted about a week. Still glad I had the third shot.

14 Posts
I had my 3rd dose last week as well in ON. I had to wait for a letter from my oncologist to say I qualified. In the letter it recommended, but not absolute, that the 3rd dose match dose 1 & 2. So I had Pfizer. Starting the next day, I had flu like symptoms which lasted for about 36 hrs. My arm was sore for a week. I'm glad to know that I now have better coverage from the vaccine.
9 Posts

another BC resident. I had my third dose last night, I had the option of Moderna or Pfizer but Moderna was recommended for better protection against the delta variant . My arm is sore and I had a hard time sleeping last night but so far OK.

9 Posts

Here is a study that shows that those on chemo for solid tumors do not have as much protection with only two shots and 5at a 3rd is needed .

Me too. Arm very sore but so far that’s it. Same reaction as first 2 before I started this ‘journey’

329 Posts
Had my third shot yesterday, Pfizer for all three. A sore arm today, but it’s raining rhinos and elephants anyway, so a good day to stay home and take it easy.
Cynthia Mac
3338 Posts
A friend of mine mentioned that a possible reason they’re recommending Moderna for the booster is that Moderna “doesn’t hold back.”

The analogy she gave was like chemo: some people get chemo at 80% dosage - in my dad’s case, they started him at 100% and dropped him back to 80% when he proved to be struggling a bit.

Apparently Pfizer’s boosters don’t have the “full kick” of active ingredient, where Moderna does.

WestCoastSailor‍ - would chime in to let me know you heard what I heard? 😀
2 Posts
Hello, I had Mantle Cell Lymphoma and was treated earlier this year with chemo Bendamustine (impacts T cells} and Rituxamib (impacts B Cells) leaving me immune compromised. Had the third vaccine in Saskatoon about 4 weeks ago and had no reaction, not even a sore arm. A specialist oncologist in US said those who are on BR treatment are less likely to have B Or T cell response to Vaccines. Recommendation was get vaccinated but be Very Careful.
6 Posts
My husband is currently in hospital getting treatment for a yeast infection that has gone into his blood stream but hopes to be released early this week.

While he was in he missed his appointment for this third shot and started advocating for a mobile clinic to come to the hospital and provide vacinations
for those who need it. Low and behold the next day a team was through the hospital and everyone that wanted their shot got one! He is so proud of
himself since he usually is very undemanding and this has given him a boost in his confidence in his fight against this disease. Coincidence or not, he
is taking credit and the family is very proud of him.

In BC they are giving Moderna if you had Phizer for the first two shots so all the bases are covered.

I had my 3rd dose on Friday, 15th. I had Pfizer for the first 2. The nurse asked me what I wanted and asked for Pfizer. I felt that my body was used to that drug and to stick with it. If the nurse had suggested something else I would have done what she suggested. I had the same side effects as my second dose.

38 Posts

Wait for the invite from your healthcare team. They know what's best for you!

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My husband has CLL that changed to Richter's Transformation. He is currently on Ibrutinib.

He was called by our public health to come in for his 3rd dose of PFIZER in August.

I am always trying to find studies on CLL, treatments and vaccines and have come across this study.

I don't know if I copied the link correctly.

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