Comparing Heterologous and Homologous COVID-19 Vaccination: A Longitudinal Study of Antibody Decay
Chiara Orlandi,
Giuseppe Stefanetti,
Simone Barocci,
Gloria Buffi,
Aurora Diotallevi,
Ettore Rocchi,
Marcello Ceccarelli,
Sara Peluso,
Daniela Vandini,
Eugenio Carlotti,
Mauro Magnani,
Luca Galluzzi,
Anna Casabianca
Affiliations
Chiara Orlandi
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Giuseppe Stefanetti
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Simone Barocci
Department of Clinical Pathology, Azienda Sanitaria Unica Regionale Marche Area Vasta 1 (ASUR Marche AV1), Viale Comandino 70, 61029 Urbino, PU, Italy
Gloria Buffi
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Aurora Diotallevi
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Ettore Rocchi
Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti 9, 40138 Bologna, BO, Italy
Marcello Ceccarelli
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Sara Peluso
Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna, BO, Italy
Daniela Vandini
Department of Clinical Pathology, Azienda Sanitaria Unica Regionale Marche Area Vasta 1 (ASUR Marche AV1), Viale Comandino 70, 61029 Urbino, PU, Italy
Eugenio Carlotti
Department of Prevention, ASUR Marche AV1, Viale Comandino 21, 61029 Urbino, PU, Italy
Mauro Magnani
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Luca Galluzzi
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
Anna Casabianca
Department of Biomolecular Sciences, Section of Biochemistry and Biotechnology, University of Urbino Carlo Bo, Via Arco d’Augusto 2, 61032 Fano, PU, Italy
The humoral response after vaccination was evaluated in 1248 individuals who received different COVID-19 vaccine schedules. The study compared subjects primed with adenoviral ChAdOx1-S (ChAd) and boosted with BNT162b2 (BNT) mRNA vaccines (ChAd/BNT) to homologous dosing with BNT/BNT or ChAd/ChAd vaccines. Serum samples were collected at two, four and six months after vaccination, and anti-Spike IgG responses were determined. The heterologous vaccination induced a more robust immune response than the two homologous vaccinations. ChAd/BNT induced a stronger immune response than ChAd/ChAd at all time points, whereas the differences between ChAd/BNT and BNT/BNT decreased over time and were not significant at six months. Furthermore, the kinetic parameters associated with IgG decay were estimated by applying a first-order kinetics equation. ChAd/BNT vaccination was associated with the longest time of anti-S IgG negativization and with a slow decay of the titer over time. Finally, analyzing factors influencing the immune response by ANCOVA analysis, it was found that the vaccine schedule had a significant impact on both the IgG titer and kinetic parameters, and having a Body Mass Index (BMI) above the overweight threshold was associated with an impaired immune response. Overall, the heterologous ChAd/BNT vaccination may offer longer-lasting protection against SARS-CoV-2 than homologous vaccination strategies.
