Is there a way to assay immune titers in humans post vaccination?
If so, how long after immunization with vaccinia does the immune titer continue to rise? Previous exposure to smallpox or smallpox vaccine has been historically detected by neutralization antibody test, haemagglutinin-inhibiting antibody tests and complement fixation tests of the person’s serum. Neutralizing antibodies develop on average 10 days after primary vaccination and 7 days after revaccination. The levels of antibody reported by these test indicate only exposure, and the protective antibody titer against smallpox infection is unknown. Smallpox vaccination provides high level immunity for 3 to 5 years with decreasing levels thereafter with the antibody persisting for more than 10 years. Someone who was vaccinated decades ago may retain some immunity but it is not known for certain that this level of immunity would protect them from smallpox.
