mRNA vaccination drives differential mucosal neutralizing antibody profiles in naïve and SARS-CoV-2 previously-infected individuals

Two doses of BNT162b2 mRNA vaccine induces a strong systemic SARS-CoV-2 specific humoral response. However, SARS-CoV-2 airborne transmission makes mucosal immune response a crucial first line of defense. Therefore, we characterized SARS-CoV-2-specific IgG responses induced by BNT162b2 vaccine, as well as IgG responses to other pathogenic and seasonal human coronaviruses in oral fluid and plasma from 200 UK healthcare workers who were naïve (N=62) or previously infected with SARS-CoV-2 (N=138) using a pan-coronavirus multiplex binding immunoassay (Meso Scale Discovery®). Additionally, we investigated the impact of historical SARS-CoV-2 infection on vaccine-induced IgG, IgA and neutralizing responses in selected oral fluid samples before vaccination, after a first and second dose of BNT162b2, as well as following a third dose of mRNA vaccine or breakthrough infections using the same immunoassay and an ACE2 inhibition assay. Prior to vaccination, we found that spike-specific IgG levels in oral fluid positively correlated with IgG levels in plasma from previously-infected individuals (Spearman r=0.6858, p<0.0001) demonstrating that oral fluid could be used as a proxy for the presence of plasma SARS-CoV-2 IgG. However, the sensitivity was lower in oral fluid (0.85, 95% CI 0.77-0.91) than in plasma (0.94, 95% CI 0.88-0.97). Similar kinetics of mucosal and systemic spike-specific IgG levels were observed following vaccination in naïve and previously-infected individuals, respectively. In addition, a significant enhancement of OC43 and HKU1 spike-specific IgG levels was observed in previously-infected individuals following one vaccine dose in oral fluid (OC43 S: p<0.0001; HKU1 S: p=0.0423) suggesting cross-reactive IgG responses to seasonal beta coronaviruses. Mucosal spike-specific IgA responses were induced by mRNA vaccination particularly in previously-infected individuals (71%) but less frequently in naïve participants (23%). Neutralizing responses to SARS-CoV-2 ancestral and variants of concerns were detected following vaccination in naïve and previously-infected participants, with likely contribution from both IgG and IgA in previously-infected individuals (correlations between neutralizing responses and IgG: Spearman r=0.5642, p<0.0001; IgA: Spearman r=0.4545, p=0.0001). We also observed that breakthrough infections or a third vaccine dose enhanced mucosal antibody levels and neutralizing responses. These data contribute to show that a previous SARS-CoV-2 infection tailors the mucosal antibody profile induced by vaccination.

Author list



  1. Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
  2. Pandemic Sciences Institute, University of Oxford, Oxford, United Kingdom
  3. Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
  4. Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
  5. Nuffield Department of Clinical Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
  6. Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
  7. Nuffield Department of Clinical Medicine, Oxford Centre For Global Health Research, University of Oxford, Oxford, United Kingdom
  8. Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
  9. Translational and Clinical Research Institute Immunity and Inflammation Theme, Newcastle University, Newcastle, United Kingdom
  10. Department of Infection and Tropical Medicine, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, United Kingdom
  11. Translational Gastroenterology Unit, University of Oxford, Oxford, United Kingdom
  12. NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
  13. Institute of Cancer and Genomic Science, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom
  14. University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
  15. NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
  16. Liverpool University Hospitals NHS Foundation Trust, Liverpool, United Kingdom


Stephanie Longet1,2*, Alexander Hargreaves1,2, Saoirse Healy1,2, Rebecca Brown3, Hailey R. Hornsby3, Naomi Meardon4, Tom Tipton1,2, Eleanor Barnes5,6, Susanna Dunachie5,6,7,8, Christopher J. A. Duncan9,10, Paul Klenerman5,6,11,12, Alex Richter13,14, Lance Turtle15,16, Thushan I. de Silva3,4† and Miles W. Carroll1,2

Novel Coronavirus SARS-CoV-2


Frontiers in Immunology