Humoral responses to wild type and ancient BA.1 SARS-CoV-2 variant after heterologous priming vaccination with ChAdOx1 nCoV-19 and BNT162b2 booster dose

• Published in: Clinical and experimental medicine Vol. 24; no. 1; p. 12
• Main Authors: Sanna, Giuseppina, Marongiu, Alessandra, Firinu, Davide, Piras, Cristina, Palmas, Vanessa, Galdiero, Massimiliano, Atzori, Luigi, Caria, Paola, Campagna, Marcello, Perra, Andrea, Costanzo, Giulia, Coghe, Ferdinando, Littera, Roberto, Chessa, Luchino, Manzin, Aldo
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 20.01.2024; Springer Nature B.V
• Subjects: Antibodies; Antibodies, Viral; Antibody response; BNT162 Vaccine; ChAdOx1 nCoV-19; COVID-19 - prevention & control; Hematology; Humans; Immunization; Immunoglobulin G; Internal Medicine; Medical personnel; Medicine; Medicine & Public Health; mRNA; Oncology; SARS-CoV-2 - genetics; Severe acute respiratory syndrome coronavirus 2; Thrombocytopenia; Vaccination; Vaccines; COVID-19; Omicron BA.1; BNT162b2 vaccine; Anti-S-IgG; Neutralizing antibodies; Booster; ChAdOx1-S vaccine
• ISSN: 1591-9528; 1591-8890; 1591-9528
• DOI: 10.1007/s10238-023-01276-x

Several countries have recommended a booster dose of Pfizer BNT162b2 vaccine for subjects under the age of 60, who have already received the first dose of ChAdOx1. This is due to several ChAdOx1 vaccine-associated adverse vascular events and thrombocytopenia. Neutralization assay and quantitative IgG anti-SARS-CoV-2 Spike antibody (anti-S-IgG) were conducted to investigate the long-term responses to vaccine treatment in a cohort of Sardinian participants, who have received heterologous Prime–Boost Vaccination via ChAdOx1 vector vaccine and a booster dose via BNT162b2. The obtained results were compared with those of a cohort of healthcare workers (HCW) who received homologous BNT162b2 (BNT/BNT/BNT) vaccination. One month (T2) and five months after the second and before the third dose (T3), anti-spike antibody or neutralizing titers in the subjects vaccinated with ChAdOx1-S/BNT162b2 were significantly higher than those who experienced the ChAdOx1-S/ChAdOx1-S or BNT162b2/BNT162b2 schedule. These results suggest that a ChAdOx1-S/BNT162b2 regimen provides a more robust antibody response than either of the homologous regimens. However, the anti-spike antibodies or neutralizing titers after the third injection (mRNA vaccine) of ChAdOx1-S as a second dose and BNT162b2 were not statistically different. Homologous and heterologous vaccination provided a strong antibody response. Neutralizing activities were also described against the Omicron BA.1 variant in a sub-group (40) representative of the three vaccination regimens among our cohort.