Developing new vaccines is expensive, and if the target population is mostly in poor countries, there's nobody to foot the bill. That's why these diseases are called "neglected".

https://en.wikipedia.org/wiki/Neglected_tropical_diseases#Ec...

heh, i almost upvoted your comment, but then you contradicted the main reasoning at the end.

(intervention in a complex system, and without proper testing at that... even if the covid vaccines were safe, that was by luck)