[set fair (OP)]

And would it be better to put twice as much of the variant?

Personally I think governments / health authorities should explicitely allow a mix and match of vaccines so that they can give the first one available to inlude 501V2 as the booster. The only arguement I have come across against mix and match is that it hasn't been trialed - but neither has a longer gap between jabs. We have seen too much wait and see. If we carry on giving the existing vaccines as a booster and later decide that 501V2 needs to be vaccinated against, then we have effectively wasted a dose of vaccine.

I can see that this is by no means a clearly we should do this thing. What do you think?

[Kryptid]

If we carry on giving the existing vaccines as a booster and later decide that 501V2 needs to be vaccinated against, then we have effectively wasted a dose of vaccine.

Not really. Being immunized against any COVID variant is beneficial. The current evidence is that vaccines are still effective against mutant strains (albeit at a somewhat reduced level).

[Bored chemist]

Given a choice between a fairly good vaccine now and maybe a better one at some point sometime in the future, I'd go for what I can get quickly.
In the midst of a plague the list of things we should wait for, before taking action, is pretty short

[set fair (OP)]

Given a choice between a fairly good vaccine now and maybe a better one at some point sometime in the future, I'd go for what I can get quickly.
In the midst of a plague the list of things we should wait for, before taking action, is pretty short

We could still use the existing vaccine as a first dose, so no slowdown in the daily number of jabs.

[evan_au]

Apparently the mRNA and live-virus vaccines recruit more of the immune system than protein-based vaccines.
- So one of the protein-based vaccines (NovaVax) is being rejigged with a booster dose optimized for the new strain against which the current formulation is less effective.
- It will be interesting to see how the approval authorities will treat the new formulation from the viewpoint of clinical trials. Will it take another 6 months before general deployment?

But the currently-approved vaccines in "Western" countries are based on mRNA or live but non-replicating virus.

This is one of the topics discussed by Dr Chris Smith here (listen 2:20-7:02):
https://www.thenakedscientists.com/podcasts/short/covid-vaccines-eu-debacle

[Bored chemist]

Given a choice between a fairly good vaccine now and maybe a better one at some point sometime in the future, I'd go for what I can get quickly.
In the midst of a plague the list of things we should wait for, before taking action, is pretty short

We could still use the existing vaccine as a first dose, so no slowdown in the daily number of jabs.

As far as I can tell, my logic applies equally well to a second jab.