What public health expertise do you believe Bill Gates personally contributed to the The Global Polio Eradication Initiative? As far as I can tell, Bill Gates contributed $110 million USD to The Global Polio Eradication Initiative in funding, but personally contributed no polio eradication expertise at all to that project.

There is no basis at all for claiming he’s a public health expert. He might be an effective philanthropist, but that’s a completely different topic.