Is that true though?
There's the Covax programme, with the UK pleding £500m, there's the Ox/AZ vaccine developed by the UK and made available to the world at cost, if that's "vaccine nationalism" then more of the same please.
There's a counterpoint that if countries (and companies) that invested heavily in vaccine development and production don't see a return then nobody gets any vaccines, and the UK's domestic production is far too small to make an impact on a global scale anyway.
In fact the biggest mistake the EC made was not investing in production early, which has left EU production far behind where it could've been, so in that respect the right sort of "vaccine nationalism" would've been a good thing, both for the EU and the rest of the world.