Indications for Use
Neutralization antibody testing may be interpreted in the following ways:
In a person who has never been vaccinated:
Testing positive for antibody against the N protein (Nucleocapsid) indicates prior natural infection
In a person who has been vaccinated:
Testing positive for antibody against the vaccine antigen target, such as the S protein, and negative for N or RBD suggests that they have produced vaccine-induced antibody and that they were never infected with SARS-CoV-2
Testing positive for any antibody other than the vaccine-induced antibody, such as the N protein, indicates resolving or resolved SARS-CoV-2 infection that could have occurred before or after vaccination.