Mixing and matching of vaccines - trial

[CrunchyCarrot]

There's going to be a trial to see whether people have equivalent or better immunity by giving 2 different vaccines rather than the same one. I suppose if it works, that would help a lot with logistics of having to give people the same vaccine as they had for their first dose.

Obviously wouldn't apply to those who cannot get one or other of the vaccines due to allergies, but still, would increase flexibility of delivery, and might even prove more effective against different variants.

The trial, which is being run by Oxford University and is funded by the government’s vaccine taskforce, has been described by ministers as “hugely important”.

It will recruit 820 people over the age of 50 who have not yet had a vaccine, to receive a first dose of either the Oxford/AstraZeneca vaccine or the Pfizer/BioNTech vaccine. Some people will then get an alternative vaccine at a second appointment within 12 weeks, and others will get the same vaccine again.

www.bbc.co.uk/news/health-55924433

www.theguardian.com/society/2021/feb/04/oxford-trial-to-test-efficacy-of-mix-of-covid-vaccines-for-individuals

I am not sure . We just need any vaccine at all that works safely and effectively and with the possibility of new variants now and in the future
being the first consideration.
I would rather see the research done on that basis first

Is 840 enough people. Isn't that how they got into the mess with the over 65s arm? It's not going to be much good if they end up with say 50% efficacy and a CI of -200% to 90%.

Reasonable enough for an initial trial but not the sort of thing you'd want to base public policy on.

@RafaIsTheKingOfClay

Is 840 enough people. Isn't that how they got into the mess with the over 65s arm? It's not going to be much good if they end up with say 50% efficacy and a CI of -200% to 90%.

Reasonable enough for an initial trial but not the sort of thing you'd want to base public policy on.

I just wanted to say that at the ripe old age of 48 I have just learned what a CI is . I still hate research methods though

I wonder how the trial will work. Can they really recruit people happy to have a placebo vaccine at this point?

They won't get a placebo though. At this stage they will be comparing standard treatment (two doses same vaccine) with alternative treatment (two doses different vaccines) and seeing which one has the stronger immune response. At least there will be some data in case the almost inevitable supply problems occur and we will know how useful it is. If some work better in some people than others then mixing might have benefits.

It depends on the individual variability of the response to the vaccines as to whether 840 is enough people. I imagine by now they have a good idea of that and there isn't currently a shortage of vaccines or volunteers, plus there isn't the original time pressure, so I imagine the design is sufficiently powered.

They can run the stats, see if it's powered enough. 840 sounds plausible for 80% confidence in the 95% CI if monitored over enough time.

I'm over 50 (they are only recruiting age 50+) but I am too far away & don't want any jabs anyway.