Antibodies to SARS-CoV-2 in a Medical School Department of Pediatrics

ABSTRACT

Background. Healthcare workers are at high risk of Covid-19 (C19) infection and received priority for C19 vaccinations. Therefore, we conducted a serosurvey to determine anti-C19 antibodies and evidence of C19 infection in health care employees who did or did not have direct contact with patients. Methods. 49 participants provided finger stick blood samples collected onto filter papers and tested for antibodies to C19 using Bio-Plex Pro Human SARS-CoV-2 IgG reagents. Antibodies to C19 nucleocapsid (N), receptor-binding domain (RBD), spike 1 (S1), and spike 2 (S2) were measured. Samples were collected 8 to 11 months after C19 vaccines were made available. Results. All participants received two doses of Pfizer BioNTech or Moderna RNA-based C19 vaccines, and all showed serological evidence of antibodies to C19 RBD, S1, and S2. Antibodies to N, considered a marker of C19 infection, were detected in 16 individuals, of whom 10 reported having a PCR documented C19 infections. 6 individuals had evidence of C19 infection of which they were not aware. Antibody levels were notably higher following infection and for not infected participants following Pfizer-BioNTech vaccination. There was a 20% higher infection rate in participants with direct patient contact. Conclusion. This vaccinated population had significant rates of strong antibody responses to C19 infection and a notable rate of C19 infections, most notable in those providing direct patient care.