Approved / mass vaccines are not 100% effective all the time. Trials are stochastic in nature and experiments are designed to avoid bias. Assume for this question that the vaccine has passed regulatory trials / hurdles and is in mass production.
It would be of scientific interest, if not intellectual curiosity, to be able to confirm immunity of a particular vaccinated person. For example, if we wanted to verify a specific vaccinated doctor or other front line worker has conferred immunity to a pathogen. If it advances the question, assume, Dr. Tony Fauci is the physician.
If a person is vaccinated and seeks to confirm immunity (COVID-19):
- can this be performed in-vitro?
- If not, why?
- Is immunity confirmation verifying antibody concentration?