When COVID descended from the sky, oooooooh it seems like two days or a thousand years ago, there was an initial commitment to global working-together, hands-across-the-etc. And then the nations of the world fell into an unseemly heap in their scramble for the vaccines which appeared in a haphazard fashion, before reassembling some modicum of decency and creating COVAX, the scheme to share vaccines worldwide.
Then, after it became clear that booster shots would be necessary, the scramble started afresh, on top of what was already a stuffed-up process.
And then the Omicron strain appeared out of Africa to remind us of what happens when you treat a global disease in a global society as a series of national epidemics. After some mumbling about "vaccine nationalism", the appearance of the new strain prompted nations like the UK to ... loosen requirements for booster shots, and shorten the gap between to three months, from six.