Not a paper, but perhaps worth reading, is this article, which discusses other conflict of interest accusations. https://economictimes.indiatimes.com/industry/healthcare/bio...

The point of this article appears to be that the Gates foundation simultaneously promotes vaccination and helps pharmaceutical companies with their vaccine research. While that is technically a conflict of interest...it's not much of one. They do both of those things vaccines because vaccines save millions of lives per year.

It'd be like saying it's a conflict of interest to promote access to clean water, while also investing in companies that supply clean water. Sure. It's a conflict. It's also exactly what you would do if you just wanted people to have clean water.