At present the patient is used as source for the "seed" antigen, which is subsequently multiplied in cell cultures to obtain all the antigens for a vaccine. Disadvantages are long time of vaccine fabrication and possibility to introduce non-human proteins.

What if we collect all the antigens for a vaccine from a single patient who has been previously screened not to carry other disease than the target one?

Details at: Preprint NEW VACCINES AGAINST RESPIRATORY TRANSMITTED DISEASES

A single patient could produce enough antigen for thousands of doses of vaccine which can be produced in minutes, not in months.

You probably observed that the above is asked by an engineer, but for world's sake in this crisis, why not inspect unorthodox avenues?

Thank you for your time to respond!