None.
The critical issue is know-how. Patents have not been the blocking factor here. Of course, you need to have access to any patents, but they can even be worked around. The critical issue for biologics is know-how. If you don't have the know-how....
Moderna has said that they were not going to block their patents from the beginning, but nobody has been able to make the Moderna vaccine because they don't have the know-how. It's the know-how that's critical.