A two-arm analysis of the immune response to heterologous boosting of inactivated SARS-CoV-2 vaccines

• Published in: Scientific reports Vol. 13; no. 1; pp. 18762 - 11
• Main Authors: Nithichanon, Arnone, Kamuthachad, Ludthawun, Salao, Kanin, Phoksawat, Wisitsak, Kamsom, Chatcharin, Wongratanacheewin, Surasakdi, Pipattanaboon, Chonlatip, Kanthawong, Sakawrat, Yordpratum, Umaporn, Aromseree, Sirinart, Meesing, Atibordee, Mootsikapun, Piroon, Edwards, Steven W., Phanthanawiboon, Supranee
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 31.10.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250; 631/326; 631/326/590; Antigens; CD4 antigen; CD8 antigen; COVID-19; COVID-19 vaccines; Deoxyribonucleic acid; DNA; DNA viruses; Humanities and Social Sciences; Immune response; Immunity; Immunological memory; Lymphocytes; Lymphocytes T; Memory cells; mRNA; multidisciplinary; Pandemics; Phenotypes; Risk groups; Science; Science (multidisciplinary); Severe acute respiratory syndrome coronavirus 2; Vaccines; γ-Interferon
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-46053-8

Several vaccine programs were introduced during the COVID-19 pandemic, which included inactivated virus, DNA viral vectors and mRNA vaccines. Booster programs are recommended, especially for those in high-risk groups. However, many of these booster programs involve heterologous vaccines. This study enrolled volunteers who first received two full-dose CoronaVac vaccinations before receiving heterologous boosters with DNA- and/or mRNA-vaccines for an additional 2 doses (n = 40) or an additional 3 doses (n = 16). Our results showed no difference in side effects, neutralizing antibodies, or T-cell responses for any of the heterologous vaccination programs. However, the neutralizing capacity and IFN-γ responses against the Omicron variant in volunteers who received 4 or 5 doses were improved. Polarization of peripheral memory T cells after stimulation in all booster groups with Omicron peptide showed an increased trend of naïve and central memory phenotypes of both CD4+ and CD8+ T cells, suggesting that exposure to Omicron antigens will drive T cells into a lymphoid resident T cell phenotype. Our data support a continuous vaccination program to maximize the effectiveness of immunity, especially in people at high risk. Furthermore, the number of boosting doses is important for maintaining immunity.