The $900,000 you say is required to develop a new mercury free version of the Staphylococcus vaccine. However, what about just restarting production of the original mercury containing Staphylococcus vaccine (in a country where it is legal to do this)? Presumably that would not cost much.
I think the important thing would be to perform some proper studies on this Staphylococcus vaccine, and publish data on its efficacy for ME/CFS. I don't think there is any data, as far as I am aware, except anecdotal info.
Once there is a published a study on the efficacy of Staphylococcus (and assuming it does have good efficacy), then you can consider creating a mercury free vaccine. And if a restarted production of the mercury containing vaccine was really helping thousands of ME/CFS patients to get significantly better, I don't think you would have any difficulty in raising the $900,000.
Only recently nearly
half a $million was raised in just 90 days by crowdsourcing from the ME/CFS community to perform a rituximab trial. I think the money would be raised if the data of efficacy was there.