Mixing increases reports of mild side-effects

[TruelyWonder]

Adults are more likely to report mild and moderate side-effects after mixing doses of the AstraZeneca and Pfizer Covid vaccines, a study indicates.

www.bbc.com/news/health-57075503

Adults are more likely to report mild and moderate side-effects after mixing doses of the AstraZeneca and Pfizer Covid vaccines, a study indicates.

www.bbc.com/news/health-57075503

Lancet paper here:

secure.jbs.elsevierhealth.com/action/getSharedSiteSession?redirect=https%3A%2F%2Fwww.thelancet.com%2Fjournals%2Flancet%2Farticle%2FPIIS0140-6736%2821%2901115-6%2Ffulltext&rc=0

Conclusion:

Pending availability of a more complete safety dataset and immunogenicity results for heterologous prime-boost schedules (to be reported shortly), these data suggest that the two heterologous vaccine schedules in this trial might have some short-term disadvantages. Routine prophylactic use of paracetamol after immunisation could help mitigate these7 and is being studied in Com-COV participants receiving prime and boost vaccines at 12-week intervals. Regardless, it is reassuring that all reactogenicity symptoms were short lived, and there were no concerns from the limited haematology and biochemistry data available. Further studies evaluating heterologous prime-boost schedules, incorporating vaccines manufactured by Moderna and Novavax, are ongoing, and are crucial to informing the appropriateness of mixed COVID-19 vaccine schedules.

Worth noting all participants were over 50 and side effects likely to be even higher in under 50s.

Professor Snape says the main things is that they don't vaccinate all the nurses on one ward at a time. You wouldn't want lots of them off sick the next day. I love the way he thinks

Yes that is true. Younger people are reporting worst side effects with our existing uses. At first I just thought older people were less wimpy but it turns out to be an actual real thing

@TruelyWonder

Yes that is true. Younger people are reporting worst side effects with our existing uses. At first I just thought older people were less wimpy but it turns out to be an actual real thing

Yep! What I found interesting and surprising is that two doses of AZ induces less side effects than two doses of Pfizer in the over 50s.

There is something I didn't know.

I do would if we will look back on all this and realise we got the vaccines the wrong way around. Az should have been given to more old people and Pfizer to the young. AZ is better at stopping hospitalisations and deaths. Pfizer is better at stopping infection. The real world data shows not much in it bit still. Perhaps if they all got AZ we could have saved more elderly. It seems to stop hospitalisations pretty quick after one dose.

I thought the Com cov study was first dose had been Pfizer/AZ, The second was Novavax/Moderna

Study says: Overall, both mixed-dose schedules triggered more side-effects. For instance, feverishness was reported by 34% of patients who got Oxford/AstraZeneca followed by Pfizer/BioNTech; and 41% of those given Pfizer/BioNTech followed by Oxford/AstraZeneca. Meanwhile, only 10% reported feeling feverish in the group who received both Oxford/AstraZeneca doses; and 21% reported the symptom in the group that received two Pfizer/BioNTech doses.

That is pretty miserable. At least a third of all trial participants, older in the first place, had fever!

The main thing is if intensity of these side effects correlates with severity, and higher incidence of blood clots. For that reason, I am sticking to receiving the second doae of my AZ.

I think we still need to see the final research results. This is only one element of the study after all. Some amazing effectiveness result at stopping infection could be reported by mixing you never now. Though I don't think you can get a lot better than some of the real world data we are seeing.

I’m in the study and had my boost after 4 weeks. I think the other half of the participants are about to have their boost after 12 weeks. I had a sore arm after the prime but was feverish after the second. I suspect I had Pfizer then AZ but will have to wait to next year to find out. Looking forward to hearing more about the efficacy of mixing - hopefully next month.

It does bring up questions about the proposed "booster" for over 50s this autumn. Would presume it would be generic rather than having the same as the original 2 vaccines.

Perhaps this really is a case of higher side effects being due to stronger immune response. There is an issue with that in that the vaccines are already highly effective; excessive side effects suggests to me that perhaps they should simply reduce the dose for younger people. There's no need to increase vaccine efficacy that's already over 90%, but there is a need to reduce side effects - not just the extremely rare serious effects, but even very mild effects like chills or headache are causing anxiety and affecting take-up globally.

@TruelyWonder

There is something I didn't know.

I do would if we will look back on all this and realise we got the vaccines the wrong way around. Az should have been given to more old people and Pfizer to the young. AZ is better at stopping hospitalisations and deaths. Pfizer is better at stopping infection. The real world data shows not much in it bit still. Perhaps if they all got AZ we could have saved more elderly. It seems to stop hospitalisations pretty quick after one dose.

AZ isn't better at preventing hospitalisation and death. I assume you're referring to the Scottish study data from April, more up to date data from the same study shows Pfizer is more effective.

QueenI presume you are referring to this latest data.

PHE data shows:
•Two doses of Pfizer’s vaccine reduces risk of COVID-19 related death by 97% (one dose reduces risk by 80%)

•One dose of Astrazeneca’s vaccine ALSO reduces risk of COVID-19 related death by 80% (data on two doses is not available yet)

As you can see they only looked at one dose with AZ compared with two doses of Pfizer.

Across the board though found that both vaccines are on par with each other.

Data from around the world is now showing that Pfizer has a slight advantage in limiting infection but AZ has a slight advantage in cutting hospitalisation. In real world data there isn't a great deal in it though. Mostly because once you have antibodies and your immune system memory you wouldn't know which vaccine was responsible.

No, I'm talking about the Scottish study.

www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00677-2/fulltext

"We found that vaccine effect at 28–34 days post-vaccination against COVID-19 hospital admissions among those receiving the first dose of the vaccine BNT162b2 was 91% (95% CI 85–94) and for ChAdOx1 was 88% (75–94; table 2)."

The difference was more pronounced for the elderly.

"Among those aged 80 years and older at 28–34 days post-vaccination, vaccine effect against COVID-19 hospital admission for those who received the first dose of the BNT162b2 mRNA vaccine was 88% (95% CI 76–94), and for ChAdOx1 was 81% (60–91; table 3)."

I think the clue there is it says 28 -34 days post vaccine and is talking about one dose.

We already know AZ takes longer to build up antibodies. That a gap of 8 to 12 weeks works best. So research wise this is old news really.

I am actually really impressed that AZ was found to have such a high percentage so early on. That is marvellous news. So thnk you for posting that.

I mean one age group only 3% between them and the other age group only 7% between them. When AZ is at its weakest moment one a month after first dose. That just goes to how amazing these vaccines are❤

That is not good news for anyone who had AZ. As they are unlikely to want it going forward... Especially if under 50 for boosters.
Nor i guess if the plan might be to use Az on older people if they originally had pfizer

@HSHorror

That is not good news for anyone who had AZ. As they are unlikely to want it going forward... Especially if under 50 for boosters. Nor i guess if the plan might be to use Az on older people if they originally had pfizer

Worse side effects for Pfizer or mix than AZ = bad news for people who had AZ. Eh???? Ugur, is that you?

@HSHorror

That is not good news for anyone who had AZ. As they are unlikely to want it going forward... Especially if under 50 for boosters. Nor i guess if the plan might be to use Az on older people if they originally had pfizer

Given the data here does that make sense?

It presents interesting issues for the planned Pfizer booster shots in autumn. I suspect they will simply recommend paracetamol use. Makes it less likely healthy under 50s will be offered a booster anytime soon, though.

I hope it means the gov is less inclined to start mixing and matching current initial doses. Canada seems to be the most invested in that approach given they panicked and vaccinated a bunch of people with AZ and are now likely to offer them mRNA second doses due to supply and clotting issues.

ComCov2 is in people who have already had their first vaccine (to speed up the results)
At 8-12 weeks:
If they had AZ first they get either AZ, Moderna or Novavax second, if they had Pfizer first they get either Pfizer, Moderna or Novavax second, so no mixing of AZ & Pfizer (because that's already being done, so a waste of volunteers).
For those that like anecdata, I had AZ first with some unpleasant side effects, but nothing major (bad headache, myalgia, temperature, insomnia, sore arm), similar but milder after the second unknown dose.

Canada's main issue is supply. They know expect a shortage of AZ because they were getting it from India.

They also have some sort of hesitancy around Moderna. It is getting the same treatment there by social media etc that AZ has had here. People have been turning it down.