Bill Gates strikes me as a nerd who feels guilty that the company he started became a monopolistic multinational giant with shady ass business practices, and now he's trying to compensate for that guilty conscience by throwing money at humanitarian causes. And being a nerd, he puts his foot in his mouth.
He said in a presentation something along the lines of "if you give 3rd-worlders access to modern medicine and vaccines and raised living standards, their population should decrease by 15%". That is plausible and looking at the birth rates of the 3rd world, yes, their population growth is unsustainable, so we have a big a problem building up there.
Morons took that as "vaccines will kill off 15% of the world". That's… stupid.
And he put money into yeah giving them medicine and vaccines and shit. We're talking about a continent of over 1bn people. And yeah, there probably were thousands of cases of people who had side effects because of the vaccines he sent out, but that's just to be expected for anyone ho has even the slightest clue how statistics work. The bigger the population targeted, the more people will experience unwanted effects, but it's a statistically insignificant minority.