Immunogenicity trends 1 and 3 months after second BNT162B2 vaccination among healthcare workers in Israel

Yael Shachor-Meyouhas, Khetam Hussein, Halima Dabaja-Younis, Moran Szwarcwort-Cohen, Ronit Almog, Avi Weissman, Michal Mekel, Gila Hyams, Nethanel A. Horowitz, Vardit Gepstein, Itamar Netzer, Hagar Cohen Saban, Neta Petersiel, Jalal Tarabeia, Michael Halberthal

Research output: Contribution to journalArticlepeer-review


Objectives: We evaluated the antibody response to the BNT162B2 vaccine among healthcare workers (HCWs) to identify factors associated with decreased immunogenicity. Methods: This prospective cohort study included consenting HCWs who completed a questionnaire regarding background illnesses, medications, and post-vaccination allergic reactions or rash. All HCWs were tested for anti-spike antibodies (LIAISON SARS-CoV-2 S1/S2 IgG assay) 1 and 3 months after the second vaccine dose. A multivariate mixed linear model was adjusted to participants' data and fit to predict antibody levels after the second BNT162B2 vaccine dose, based on antibody levels at 1 month and the slope between 3 months and 1 month. Multivariate analyses identified factors associated with lower antibody levels. Results: In total 1506 HCWs were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Older age was associated with lower mean antibody levels (–1.22 AU/mL, p < 0.001, 95%CI –1.43 to –1.01). In addition, male sex (–22.16 AU/mL, p < 0.001, 95%CI –27.93 to –16.39), underlying condition (–10.86 AU/mL, p 0.007, 95%CI –18.81 to –2.91) and immunosuppressive treatment (–28.57 AU/mL, p 0.002, 95%CI –46.85 to –10.29) were associated with significantly lower mean antibody levels. Allergic reactions after vaccine administration or peri-vaccination glucocorticosteroid treatment were not correlated with antibody levels. Conclusions: Most HCWs had measurable antibodies at 3 months. Risk factors for lower antibody levels were older age, male sex, underlying condition, and immunosuppressive treatment. These factors may be considered when planning booster doses during vaccine shortages.

Original languageEnglish
Pages (from-to)450.e1-450.e4
JournalClinical Microbiology and Infection
Issue number3
StatePublished - Mar 2022

Bibliographical note

Publisher Copyright:
© 2021 European Society of Clinical Microbiology and Infectious Diseases


  • BNT162b2
  • COVID-19
  • Healthcare workers
  • Immunogenicity
  • Serology
  • Prospective Studies
  • Humans
  • Vaccination
  • Israel/epidemiology
  • Male
  • Antibodies, Viral
  • BNT162 Vaccine
  • SARS-CoV-2
  • Health Personnel
  • COVID-19/prevention & control

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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