Suppose you are the ruler of a country which views geopolitics as a zero-sum game, because your goals are incompatible with those of other nations. It is therefore in your interest to cause other governments to be distracted with internal mistrust and divisions and health crises, so that there isn't a strong unified position to take action on the world stage.

As a test of this theory, look at which countries have this sudden mistrust of authority, and which country(s) they would refuse to buy a vaccine from; then look at countries which don't have this problem and consider whose vaccine they buy.