First mix and match with vaccines. Now only 20% of a true dose to be used as booster shots to their failed vaccine of choice. Folly after folly, are they leading the world with leaps forward in vaccine use or just fooling the Thai people. One things sure they aren't fooling themselves off any Red Zone listings anytime soon.
I would argue that in South Africa and Rhodesia they did work. It did take a long time though. The other examples you give Cuba, Iran would only work if there was a carrot and a stick approach. Sadly all they have had is the stick.