Signal Transduction and Targeted Therapy, 18 April, 2022, DOI：https://doi.org/10.1038/s41392-022-00979-z
Sequential immunizations confer cross-protection against variants of SARS-CoV-2, including Omicron in Rhesus macaques
Wei Deng, Qi Lv, Fengdi Li, Jiangning Liu, Zhiqi Song, Feifei Qi, Qiang Wei, Pin Yu, Mingya Liu, Shasha Zhou, Yaqing Zhang, Hong Gao, Nan Wang, Zijing Jia, Kai Gao, Jiayi Liu, Chong Xiao, Haiquan Shang, Xiangxi Wang, Linlin Bao & Chuan Qin
Variants of concern (VOCs) like Delta and Omicron, harbor a high number of mutations, which aid these viruses in escaping a majority of known SARS-CoV-2 neutralizing antibodies (NAbs). In this study, Rhesus macaques immunized with 2-dose inactivated vaccines (Coronavac) were boosted with an additional dose of homologous vaccine or an RBD-subunit vaccine, or a bivalent inactivated vaccine (Beta and Delta) to determine the effectiveness of sequential immunization. The booster vaccination significantly enhanced the duration and levels of neutralizing antibody titers against wild-type, Beta, Delta, and Omicron. Animals administered with an indicated booster dose and subsequently challenged with Delta or Omicron variants showed markedly reduced viral loads and improved histopathological profiles compared to control animals, indicating that sequential immunization could protect primates against Omicron. These results suggest that sequential immunization of inactivated vaccines or polyvalent vaccines could be a potentially effective countermeasure against newly emerging variants.