Heterologous immunization with inactivated vaccine followed by mRNA-booster elicits strong immunity against SARS-CoV-2 Omicron variant

The recent emergence of the Omicron variant has raised concerns on vaccine efficacy and the urgent need to study more efficient vaccination strategies. Here we observed that an mRNA vaccine booster in individuals vaccinated with two doses of inactivated vaccine significantly increased the plasma level of specific antibodies that bind to the receptor-binding domain (RBD) or the spike (S) ectodomain (S1 + S2) of both the G614 and the Omicron variants, compared to two doses of homologous inactivated vaccine. The level of RBD- and S-specific IgG antibodies and virus neutralization titers against variants of concern in the heterologous vaccination group were similar to that in individuals receiving three doses of homologous mRNA-vaccine or a boost of mRNA vaccine after infection, but markedly higher than that in individuals receiving three doses of a homologous inactivated vaccine. This heterologous vaccination regime furthermore significantly enhanced the RBD-specific memory B cell response and S1-specific T cell response, compared to two or three doses of homologous inactivated vaccine. Our study demonstrates that mRNA vaccine booster in individuals vaccinated with inactivated vaccines can be highly beneficial, as it markedly increases the humoral and cellular immune responses against the virus, including the Omicron variant.

ZUO Fanglei;  ABOLHASSANI Hassan;  DU Likun;  PIRALLA Antonio;  BERTOGLIO Federico;  CAMPOS MATA Leire;  WAN Hui;  SCHUBERT Maren;  CASSANITI Irene;  WANG Yating;  SAMMARTINO Camilla;  SUI Run;  VLACHIOTIS Stelios;  BERGAMI Federica;  KUMAGAI BRAESH Makiko;  ANDRELL Juni;  ZHANG Zhaoxia;  XUE Yintong;  WENZEL Esther Veronika;  CALZOLAI Luigi;  VARANI Luca;  REZAEI Nima;  CHAVOSHZADEH Zahra;  BALDANTI Fausto;  HUST Michael;  HAMMARSTRÖM Lennart;  MARCOTTE Harold;  PAN-HAMMARSTRÖM Qiang; 

2023-09-14

NATURE PORTFOLIO

JRC129296

2041-1723 (online),   

https://doi.org/10.1038/s41467-022-30340-5,    https://publications.jrc.ec.europa.eu/repository/handle/JRC129296,   

10.1038/s41467-022-30340-5 (online),