Neutralizing antibody responses in healthcare personnel after three doses of mRNA BNT162b2 vaccine and association with baseline characteristics and past SARS-CoV-2 infection.

Aim: To estimate neutralizing antibody (NAb) immunity against SARS-CoV-2 in 739 healthcare personnel (HCP) vaccinated with three doses of BNT162b2 mRNA vaccine.

Methods: Serum samples were collected at 3, 6, and 9 months after the second vaccine dose and at 7-55 days after the third dose. Samples were tested for NAbs against SARS-CoV-2 receptor binding domain.