For this reason, Pfizer may only have exclusive distribution and production rights in the US, and if the vaccines are shipped out of it, that would require BioNTech's permission.
However, BioNTech's Singapore venture doesn't mention Pfizer as a partner on that. That points to having separate partners on this. Pfizer and/or Fosun may still be minority partners on this, or it can be with local investors.
BioNTech will be handling the negotiations, but the vaccines can come out from anyone of its partner ventures. For example, shipped from China to the Philippines.
Going outside of Pfizer and the US means BioNTech does not need US government approval for export.