Neutralization antibody testing may be interpreted in the following ways:
 

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​In a person who has never been vaccinated:

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• Testing positive for antibody against the N protein (Nucleocapsid) indicates prior natural infection

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​In a person who has been vaccinated:

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• 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

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• 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.

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