AUTHOR=He Qian , Mao Qunying , Zhang Jialu , Gao Fan , Bai Yu , Cui Bopei , Liu Jianyang , An Chaoqiang , Wang Qian , Yan Xujia , Yang Jinghuan , Song Lifang , Song Ziyang , Liu Dong , Yuan Yadi , Sun Jing , Zhao Jincun , Bian Lianlian , Wu Xing , Huang Weijin , Li Changgui , Wang Junzhi , Liang Zhenglun , Xu Miao TITLE=Heterologous immunization with adenovirus vectored and inactivated vaccines effectively protects against SARS-CoV-2 variants in mice and macaques JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.949248 DOI=10.3389/fimmu.2022.949248 ISSN=1664-3224 ABSTRACT=

To cope with the decline in COVID-19 vaccine-induced immunity caused by emerging SARS-CoV-2 variants, a heterologous immunization regimen using chimpanzee adenovirus vectored vaccine expressing SARS-CoV-2 spike (ChAd-S) and an inactivated vaccine (IV) was tested in mice and non-human primates (NHPs). Heterologous regimen successfully enhanced or at least maintained antibody and T cell responses and effectively protected against SARS-CoV-2 variants in mice and NHPs. An additional heterologous booster in mice further improved and prolonged the spike-specific antibody response and conferred effective neutralizing activity against the Omicron variant. Interestingly, priming with ChAd-S and boosting with IV reduced the lung injury risk caused by T cell over activation in NHPs compared to homologous ChAd-S regimen, meanwhile maintained the flexibility of antibody regulation system to react to virus invasion by upregulating or preserving antibody levels. This study demonstrated the satisfactory compatibility of ChAd-S and IV in prime-boost vaccination in animal models.