Comparison of Immune Responses between Inactivated and mRNA SARS-CoV-2 Vaccines Used for a Booster Dose in Mice

Viruses. 2023 Jun 11;15(6):1351. doi: 10.3390/v15061351.

Abstract

A large amount of real-world data suggests that the emergence of variants of concern (VOCs) has brought new challenges to the fight against SARS-CoV-2 because the immune protection elicited by the existing coronavirus disease 2019 (COVID-19) vaccines was weakened. In response to the VOCs, it is necessary to advocate for the administration of booster vaccine doses to extend the effectiveness of vaccines and enhance neutralization titers. In this study, the immune effects of mRNA vaccines based on the WT (prototypic strain) and omicron (B1.1.529) strains for use as booster vaccines were investigated in mice. It was determined that with two-dose inactivated vaccine priming, boosting with mRNA vaccines could elevate IgG titers, enhance cell-mediated immunity, and provide immune protection against the corresponding variants, but cross-protection against distinct strains was inferior. This study comprehensively describes the differences in the mice boosted with mRNA vaccines based on the WT strain and the omicron strain, a harmful VOC that has resulted in a sharp rise in the number of infections, and reveals the most efficacious vaccination strategy against omicron and future SARS-CoV-2 variants.

Keywords: SARS-CoV-2; VOCs; booster vaccines; mRNA vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines*
  • COVID-19* / prevention & control
  • Cross Protection
  • Humans
  • Mice
  • RNA, Messenger / genetics
  • SARS-CoV-2 / genetics
  • mRNA Vaccines

Substances

  • COVID-19 Vaccines
  • RNA, Messenger
  • mRNA Vaccines
  • Antibodies, Viral
  • Antibodies, Neutralizing

Supplementary concepts

  • SARS-CoV-2 variants

Grants and funding

This research was supported by Yunnan Fundamental Research Projects, grant numbers 202301AT070362, 202201AU070150, and 202101AT070286; the National Natural Science Foundation of China, grant number 82104130; the National Key R&D Program of China, grant number 2022YFC2305700; the Special Biomedicine Projects of Yunnan Province, grant number 202102AA310035; the Major Science and Technology Special Projects of Yunnan Province, grant number 202002AA100009; Fundamental Research Funds for the Central Universities, grant number 3332022075; Funds for the Training of High-Level Health Technical Personnel in Yunnan Province, grant number H-2019063; Funds for High-Level Scientific and Technological Talents Selection Special Project of Yunnan Province, grant number 202205AC160015; and the CAMS Innovation Fund for Medical Sciences (CIFMS), grant number 2021-I2M-1-043.