Thank you for asking such a great question.
It's actually a huge problem right now, one that affects vaccines and patented drugs overall. Simply put, everything in the current marketplace is done under the table, through confidential agreements, and everyone is in on it. As an outside analyst looking in, I have no way of knowing who is paying what and under which terms. This is the new drug marketplace: everything is done under the table without a shred of transparency regarding who is doing what in relation to a product that is essential to public health.
Take the Moderna vaccine, for example. No private money went into developing the product, and yet Moderna is charging the most of all the vaccine makers. It even won the Shkreli Award for being the worst profiteer in health care.
Moderna's vaccine was funded first and foremost by the United States government, so it's to be expected that, under their confidential agreement, the company is charging the United States a very low price. However, Moderna can charge extremely high prices outside the United States and make a large profit on a product that it did not pay to develop. Not a single cent of private money went into developing the vaccine.