[user104658]

Originally Posted by Oliver_W

Some nutters seem to think that once the elderly and vulnerable are vaccinated, the young and healthy should wait for the rest of the world to be done..

In theory if you wanted global eradication, the best path forward would be a global approach of vaccinating the elderly and vulnerable and then working down the groups in sync...

However, the sort of global organization effort needed for that doesn't exist and in the current world cannot exist, different countries are going to move at different rates, and (frankly) at least half of the global population is never even going to be offered vaccination. Global eradication is simply not possible and Covid will continue to circulate, thus, the next best option is to concentrate efforts locally to mitigate the worst of it, and probably constant vaccine development to tackle new emerging strains as they appear, if they're particularly worrying ones.