Infect Chemother.  2023 Mar;55(1):99-104. 10.3947/ic.2022.0132.

Humoral Immune Response of Heterologous ChAdOx1 nCoV-19 and mRNA-1273 Prime-Boost Vaccination against SARS-CoV-2 Variants in Korea

• Lim H
• Jang S
• In HJ
• Kim K
• Choi EB
• Kim SJ
• Lim HJ
• Yim MS
• Ouh Io
• Kim BC
• Do HN
• Lee JW
• Kim B
• Lee Yk

• KMID: 2541536
• DOI: http://doi.org/10.3947/ic.2022.0132

Abstract

The immunogenicity of a heterologous vaccination regimen consisting of ChAdOx1 nCoV-19 (a chimpanzee adenovirusvectored vaccine) followed by mRNA-1273 (a lipid–nanoparticle-encapsulated mRNA-based vaccine) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), specifically the omicron variant (B.1.1.529), is poorly studied. The aim of this study was to evaluate the neutralizing antibody activity and immunogenicity of heterologous ChAdOx1 nCoV-19 and mRNA-1273 prime-boost vaccination against wild-type (BetaCoV/Korea/KCDC03/2020), alpha, beta, gamma, delta, and omicron variants of SARS-CoV-2 in Korea. A 50% neutralizing dilution (ND50) titer was determined in serum samples using the plaque reduction neutralization test. Antibody titer decreased significantly at 3 months compared with that at 2 weeks after the 2nd dose. On comparing the ND50 titers for the above-mentioned variants of concerns, it was observed that the ND50 titer for the omicron variant was the lowest. This study provides insights into cross-vaccination effects and can be useful for further vaccination strategies in Korea.

Keyword

COVID-19 vaccine; Heterologous vaccination; Immunity; Omicron variant; Korea