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Original poster

AZ or Pfizer for 2nd dose (which would you choose?)

34 replies

QuentininQuarantino · 23/05/2021 09:22

I’m not in the UK. I’m early 30s, no health issues and have had one dose of AZ with no problems at all, very grateful.

Since then, my country has decided not to give it to younger people and has decided on giving Pfizer as the second dose. You can choose AZ but you have to sign an informed consent form.

I can’t find much data about mixing vaccines so my gut feeling would be AZ but I don’t like the idea of signing an informed consent form! Would a mixed vaccine be acceptable for travel?

I’m aware I’m in a very lucky position to have had a vaccine so early for my age and obviously wouldn’t think twice about which vaccine if I wasn’t given a choice, but I’m really bad at making decisions and need to choose, so... which would you choose?

OP posts:
Cookerhood · 23/05/2021 09:29

Pfizer. There are good reasons to think you will get a better immune response to a mix. Having said that there's no guarantee. One study showed more side effects by mixing. (I'm not an AZ critic at all btw , & am on the mixing trial here in the UK).

Original poster
QuentininQuarantino · 23/05/2021 09:35

Thanks @Cookerhood - I saw that trial and then my country did the same trial with the opposite results so I don’t know what to think! I was lucky with side effects for the first one so fingers crossed for the second. I’m leaning towards Pfizer just because I don’t want to sign something but was worried about long term efficacy. There isn’t data on that yet I don’t think is there? Thank you for being involved in the trial x

OP posts:
Cookerhood · 23/05/2021 09:48

No there isn't the data so it's a risk. The scientists have been pretty much spot on all the way so far though (working out that the longer gap would be better etc).

AlexandraEiffel · 23/05/2021 10:39

I'd pick Pfizer. I've had AZ, am a big AZ fan, but if faced with a choice I'd probably pick Pfizer. No big reason, I've no great knowledge. I think the mixing sounds promising, bit of both feels like a nice solution to me. Ultimately I'd be led by what the experts were saying, on this one knowledge is right at the cutting edge and evolving so it feels like both answers could be right. I have no desire to make this choice, and am very happy to have my 2nd AZ, but as you do, and asked, that's my 2p worth. For what it's worth I'd see this as no bad choice.

Alfaix · 23/05/2021 10:42

Pfizer. I would’ve liked one of each (had 2 AZ) and have just had Covid.
I am hoping for a booster of not AZ in Autumn as am group 2 (healthcare).

whataballbag · 23/05/2021 11:11

Pfizer all day long

Original poster
QuentininQuarantino · 23/05/2021 12:35

Thank you I will go with Pfizer then! I felt a little guilty as someone said that of the young people don’t choose AZ then they’re taking a pfizer dose off of someone else who is older but still under the AZ age limit, but I don’t want to sign a waiver and it seems mixing could be better.

OP posts:
Rainbowsandstorms · 23/05/2021 13:47

@QuentininQuarantino what did the mixing trials say in your country? I’m in a similar situation to you but we have no choice here it’s a second dose of AZ or nothing. I’m wondering if this may change. Pfizer seems to give better protection against variants but there still seems to be limited data on the efficiency of mixing. Such a hard decision to make as there’s also still very little information regarding the risk of a second dose of AZ.

Original poster
QuentininQuarantino · 23/05/2021 13:53

they said that there was no evidence of worse side effects from mixing them than having two AZ. No thrombosis but it was too small a sample group. And of course no long term data!

OP posts:
penni00 · 23/05/2021 19:09

Do you know the number of people in the trial in your country?
I would def go for Pfizer as a second dose if I was allowed (I have had many weeks of adverse effects from AZ).
It is strange that different countries are getting different results on the side effects of mixing vaccines......
Our AZ developer did a Canadian interview, and was rather negative about mixing vaccines.

penni00 · 23/05/2021 19:13

However, I am not sure about what he says tbh

WilsonMilson · 23/05/2021 19:29

This mix and match approach is a bit gung-ho to say the least, especially as the trials of mixing vaccines are no where near ending. At this point it feels like they are making it up as they go along.
I’ve no advice really as I feel for people in this situation after having an AZ first vaccine. I’d not be wild about mixing, but then I wouldn’t be happy about having an AZ second vaccine either if under 40.

TruelyStruttingHotpants · 23/05/2021 19:42

I had AZ first dose and would have it again. The reasons are:

I don't want bad side effects for second dose. Mixing vaccines has been proven to cause these. Also AZ second doses tends to have milder side effects. Pfizer second dose has worst.

Pfizer is under investigation in other countries for heart swelling. There are heart problems in my family. So don't want to trigger anything. Also now we know about the clot issue with AZ. They have sorted out a treatment for the tiny number of people affected. Plus second doses are thought to be less of an issue.

#Pfizer is not any better in real world data. AZ just takes a little longer to build up antibodies. However the hospital and deaths data is slightly better than Pfizer most the time. Plus it is working real well in India with this new variant. Pfizer has only been trial tested against it but should do ok. I like knowing my vaccine has been proven in the real world against a variant.

penni00 · 23/05/2021 21:13

@TruelyStruttingHotpants

I am feeling very sorry for myself with my side effect headaches, but I have to say when I see your user name, I can not resist a smile and a laugh:) Thank you

PinkSparklyIncorrigibleDunce · 23/05/2021 21:32

I've had my first dose of AZ and would have it for the second for the same reasons as @TruelyStruttingHotpants

penni00 · 23/05/2021 21:45

The other thing is: if there is a possibility of moving from AZ to Pfizer in the future, could it be possible that might be allowed/safe for only those who have had the one dose of AZ?

motogogo · 23/05/2021 21:52

My dd is having AZ, mixing them didn't seem to work in the trial

Motorina · 23/05/2021 21:56

I would go for Az. We have robust evidence that two doses are very safe and very effective. No, not 100%, but nothing is.

We have only speculation on the safety and efficacy of mixing doses. It may be that evidence will come, but it's not there yet.

landofgiants · 23/05/2021 22:43

I thought the vaccine mixing trial had shown increased side-effects from mixing vaccines, compared with two doses of the same thing. Side-effects for AZ tend to be worse after the first dose, so hopefully a second dose of that should not cause concerns for you. Most likely either choice would be fine. Maybe you could toss a coin?

landofgiants · 23/05/2021 22:56

In your shoes, I would choose AZ.

NicoleKidmanSuperFan · 24/05/2021 01:48

I had AZ as my first dose and was super scared to have a second dose of AZ. When I spoke to my GP she said mixing hasn’t been studied as much and not enough data is available on it. I think the participants on the AZ-Pfizer trial were only 175 people. Compare that with 9 million in the U.K. for data on two dose AZ and for me it was a no brainer. I didn’t fancy mixing. I would presume mixing will add all the possible side effects from the second brand too along with the first.
However, it could be that in a year this approach will be better or proven to be more safer/effective. Until then though I don’t fancy putting two different technologies in my body. Spent 3 months worrying about getting a second dose and I’d spend ages worrying about side effects of two different brands if I mixed them. I’m crazy enough as it is and this would really trigger me.

If your country is doing this though maybe ask them why. Have they have more cases of blood clots in the second dose out there? Or is it just because of the first dose problems? If there is no data for second dose side effects in your country then maybe go for the AZ as so far the U.K. data is showing it’s really low risk second time around. This could change though as time goes on.
To be honest I don’t think anyone knows what they’re doing anymore Grin who would have thought we’d have to jab ourselves in 2021. Booooo

Livingintheclouds · 24/05/2021 05:35

AZ. I'm getting my second dose this week.

Original poster
QuentininQuarantino · 24/05/2021 06:20

Thanks @NicoleKidmanSuperFan

I think they are doing it because of the worry about blood clots yes, but most other places are giving the second dose of AZ so it’s a bit of an outlier. I didn’t realise the uk mixing trial was such a small sample group, I think my country’s trial was 600 so a little bigger and with opposite results so I don’t know what to think!
I really wish I didn’t have a choice because I wouldn’t think twice! I just really don’t like the idea of signing an informed consent form!

OP posts:
Springchickpea · 24/05/2021 06:26

AFAIK the U.K. mixing trial (ComCov) is still running - so the data isn’t in yet. I’m pretty certain of it because I picked up a spare Pfizer dose from the ComCov trial last week.

Springchickpea · 24/05/2021 06:27

comcovstudy.org.uk/home