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Meeting with Pfizer regarding the BioNTech / Pfizer COVID vaccine

I have just finished a meeting I had with Pfizer (with several other patient groups) on the topic of their / BioNTech’s COVID vaccine  and I am pleased to say that they gave us plenty of time for questions.

It was a fascinating session, and I hope to share some of the materials with you all soon. I need to get permission from Pfizer first, but they shared some great information about how the vaccine works.

Here's their response to my questions:

How can blood cancer patients, such as CML patients taking TKIs, be confident the vaccine will be safe and effective for them?

The vaccine is not a live vaccine. This was crucial to the MHRAs decision that the vaccine is safe for use in immunocompromised people or people taking immune suppressants. It is possible that it might not be fully effective in people with a low functioning immune system, but there is no safety concern.

Lots of people with stable autoimmune diseases were included in the trial, and also patients with stable HIV, and there has been no signal of any safety concerns in those groups.

Should bone marrow transplant patients, or patients with a splenectomy be treated any differently? Can they, or stem call transplant patients take this vaccine?

Similar to above – there is no safety concern for people with a bone marrow transplant, but the vaccine might not be fully effective.

Is there any way to determine if the vaccine has produced an immune response, maybe by way of a follow-up antibody test? Could immunocompromised people need a different dose?

The regime is for two doses – that is what is authorised, so larger or more doses for some patients will not be done as it hasn’t been studied.

Real-world observation studies will look at different patient groups, and compare things like rate of infection following vaccination. Basically this means that if over time it becomes clear that people taking a particular drug seem to catch COVID more, then it would be looked at in more detail.

Since pregnant women are advised not to take the vaccines, is there any longer term potential impact on fertility?

The vaccine is contraindicated in pregnant women because there were not enough of them in the trial – so this is being extremely cautious. It’s not that pregnant women had adverse effects.

Women should do their best to avoid getting pregnant within 2 months of vaccination. Studies are planned in pregnant women so they can ascertain if it is safe. Lastly there is no evidence whatsoever that there is any ongoing impact of fertility.

Other interesting topics that came up:

• The mRNA does not, and cannot, become integrated into the genes of a person. It is a freestanding piece of genetic instruction and disintegrates and disappears from the body.

• They have strong mitigation plans in place in case of supply chain disruption caused by Brexit

• There are no egg or animal products in the vaccine

• Several reasons why they were able to run trials faster than usual, but still fully safe: Overlapping phase 1, 2, and 3 trials bought some time. The regulator (MHRA) took data on a rolling basis, as the trials went on rather than the usual method of waiting until the very end, and then start to analyse the data. Finally, a $2bn investment of producing the vaccine      at scale and at commercial risk is unprecedented and allows much faster roll-out.

David as always this is brilliant. You have had most if not all questions answered regarding this. Fantastic stuff! As always this forum delivers.

The only question outside of this vaccine and the others that are in development and it’s more a generic question how did they assure that those who were vaccinated in the trials were actually exposed to Covid to know for sure that it is indeed effective. At a guess I’d say maybe animal trials. That was more a generic question I know but one that I haven’t found the answer for and a question no one seems to be asking. I have also seen today that those who have allergic reactions of any sort should avoid the vaccine from 2 NHS workers becoming ill.

I am relieved that it shouldn’t effect us CMLers.

Again thanks for this it’s most helpful for those like me who are slightly (not much) anxious about having it. I have a lot of respect for these scientist after all it’s pioneers like these that are keeping us alive and kicking so I am confident the case is the same here.


Alex, I think it's fairly straightforward. They didn't expose to people to COVID, so relied upon community transmission to do that.

They had about 44,000 people in their Phase 3 trial - half on the vaccine arm, half on the placebo arm. Then they looked at the number of people in the placebo arm who were exposed to and caught COVID and as the arms are weighted well, you'd expect very similar exposure in the vaccine arm.

So when they looked at the data and, say, 200 people caught COVID and only a handful of those were in the vaccine arm they can derive meaningful statistics around how effective the vaccine is.

The "p value" of their analysis was exceptionally low which means that there is very very high statistical confidence that their 95% stated efficacy rate is correct.


Ah that makes sense I didn’t realise it would be that simple lol.

Thanks for explaining fully how they come to their efficacy conclusions as I was thinking surely they didn’t expose them to it and at the same time how can they confidently say it’s effective if that wasn’t the case.

Cheers David.

Hi. David 

Many thanks for this information on the Covid19 19 vaccine. I have been keeping an eye in the forum for this information

My PCR is.  0.006 and stable now for 5 years so I trust like all of us that the vaccine will be safe. 



Hi David,

Thank you for sharing. I was wondering if it would be ok with CML. Good to know. My University here in the states just received its first box of vaccines today and has a list to sign up for all faculty and frontline workers. Looks like I might be able to get a vaccine here in the next month or so. Exciting!


thank you for your input.

I am just wondering about the following part

Lots of people with stable autoimmune diseases were included in the trial, and also patients with stable HIV, and there has been no signal of any safety concerns in those groups.


Because I've read in several places that people with autoimmune diseases were excluded (most of that based on Pfizer trial info, I suppose):

Exclusion Criteria:

- Phases 1 and 2 only: Known infection with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV).

- Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.

- Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study.

Maybe Phase 3?

It would be great to see more details from Pfizer/BioNTech in that matter.

Those exclusion criteria were just for Phase 1 & 2. They weren't excluded from the Phase 3 trial.

The way it was explained to me was that they included people with stable autoimmune diseases - though they didn't give me the exact definition of that. However, I presume CML patients taking TKIs would be ruled out by the second-to-last of your bullets, but a patient in TFR maybe would not have been?

Page 37 of the trial protocol goes through the exclusion criteria.


Hi David,

I am due to get my first dose of the Pfizer vaccine today as I work for the NHS. I have had CML since January 2018 and I am on imatinib.

my PCR has been stable at 0.01. I am really anxious about getting the vaccine. Do you think it is safe for me to get it.


Hi there.

I’m not qualified to say if it’s safe, or not. But everything that the Pfizer people said seemed to me that they are exceptionally confident that it would be perfectly safe in patients like us.

I know a few CML patients who’ve had the Pfizer-BioNTech first dose and they have had zero issues besides a slightly sore arm for a few hours. 


Thank you so much  David that has really helped me I really appreciate all the hard work you have done.

Its good to know other CML patients on TKI,s have had it and have had no problems.  Did their haematologist advise it ?


Yes, from what I’ve heard from other patients in the UK, their haematologist recommended they take the vaccine. 


Thank you for this Great info. 

I am having my vaccine next week (Pfizer).

Is there any information on wether or not we should take our tki (or skip It) on the same day we get the vaccine?

I have been thinking about skipping my Sprycel dose on the day i get the vaccine, but im not sure if this is a good idea or not. (I have been in stable remission for almost 9 years now, (hovering between barely detected and pcru the last 5 years) so in my case, i am not conerned about missing one dose of tki)

Hope everyone has a Great Easter smiley

Hi Teddy,

Why do you think it would be preferable to skip your TKI on the day you have the vaccine?


Hello Sandy.

I am just thinking of taking the vaccine and TKI together might be a bit hard on the body. (In regards to side effects etc)

Maybe i am completely wrong thinking this, but would be interesting to hear some thoughts.

I usually take my TKI at around 09:00 - 10:00 after breakfast and will be having the vaccine an hour or so later.


Hi Teddy, I had the Pfizer Vaccine and my TKI with no problems and absolutely no side effects at all ,so don't think about it just do it .Denise.

Thanks for the reply.

I had my shot today, took my Sprycel a few hours after the Pfizer vaccine, so far so good smiley