I'm surprised some poorer nations haven't taken their ~million vaccine doses, split each one into 20 fractional-doses and inoculated 20 million people.

Sure, the vaccine efficiency probably drops from 93% to 15%, but it's still better to have a population of 15% resistant people than a population where 1 million get 93% protection and 19 million get 0%.

As more doses come in, the country can similarly divide them and give them as 2nd, 3rd and 4th 'boosters'. They'd probably get up to herd immunity levels with far less total vaccine...

I wonder if perhaps the contracts with vaccine producers stop them doing this? (since it might hurt the vaccines reputation)