Kinetics of dried blood spot-measured anti-SARS-CoV2 Spike IgG in mRNA-vaccinated healthcare workers

Lucrezia Puccini; Michela Fantini; Carlo Biagetti; Raffaella Angelini; Giorgio Dirani; Laura Grumiro; Pasqua Schiavone; Monica Sparacino; Simona Semprini; Vittorio Sambri; Monica Cricca

doi:10.3389/fmicb.2023.1130677

Kinetics of dried blood spot-measured anti-SARS-CoV2 Spike IgG in mRNA-vaccinated healthcare workers

Front Microbiol. 2023 Mar 1:14:1130677. doi: 10.3389/fmicb.2023.1130677. eCollection 2023.

Authors

Affiliations

¹ Operative Unit of Microbiology, The Great Romagna Hub Laboratory, Pievesestina, Italy.
² Health Services Research, Evaluation and Policy Unit, AUSL Romagna, Rimini, Italy.
³ Operative Unit of Infectious Disease, Ospedale Infermi, Rimini, Italy.
⁴ Public Health Department, Ravenna, Italy.
⁵ Department of Experimental, Diagnostic and Specialty Medicine-DIMES, University of Bologna, Bologna, Italy.

Abstract

Introduction: One of the major criticisms facing the research community during SARS-CoV2 pandemic was the lack of large-scale, longitudinal data on the efficacy of the SARS-CoV2 mRNA vaccines. Currently, even if COVID-19 antiviral treatments have been authorized by European Medicine Agency, prevention through approved specific vaccines is the best approach available in order to contain the ongoing pandemic.

Objectives: Here, we studied the antibody kinetic over a one-year period from vaccination with the Pfizer-BioNTech (Pfizer) vaccines and subsequent boosting with either the BioNTech or Moderna (Spikevax) vaccines in a large cohort of 8,071 healthcare workers (HCW). We also described the impact of SARS-CoV2 infection on antibody kinetic over the same period.

Methods: We assessed the anti SARS-CoV2 Spike IgG antibody kinetic by the high throughput dried blood spot (DBS) collection method and the GSP®/DELFIA® Anti-SARS-CoV2 IgG assay (PerkinElmer®).

Results: Our data support existing models showing that SARS-CoV2 vaccination elicits strong initial antibodies responses that decline with time but are transitorily increased by administering a vaccine booster. We also showed that using heterologous vaccine/booster combinations a stronger antibody response was elicited than utilizing a booster from the same vaccine manufacturer. Furthermore, by considering the impact of SARS-CoV2 infection occurrence in proximity to the scheduled booster administration, we confirmed that booster dose did not contribute significantly to elicit higher antibody responses.

Conclusion: DBS sampling in our large population of HCWs was fundamental to collect a large number of specimens and to clarify the effective mRNA vaccine-induced antibody kinetic and the role of both heterologous boosters and SARS-CoV2 infection in modulating antibody responses.

Keywords: COVID-19; SARS-CoV2 IgG; booster; dried blood spot; mRNA vaccine.