Int J Biol Sci 2022; 18(12):4781-4791. doi:10.7150/ijbs.72109 This issue

Research Paper

Cross-variant protection against SARS-CoV-2 infection in hamsters immunized with monovalent and bivalent inactivated vaccines

Zi-Wei Ye1,2*, Yilan Fan2*, Kaiming Tang1*, Chon Phin Ong2*, Cuiting Luo1, Hon-Lam Chung2, Tsun-Lam Leong2, Ronghui Liang1, Wai-Yin Lui2, Runhong Zhou1, Yun Cheng2, Lu Lu1, Pak-Hin Hinson Cheung2, Jasper Fuk-Woo Chan1,3, Zhiwei Chen1,3, Kwok-Yung Yuen1,3, Shuofeng Yuan1,3✉, Kelvin Kai-Wang To1,3✉, Dong-Yan Jin2✉

1. Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
2. School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
3. State Key Laboratory of Emerging Infectious Diseases, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
* These authors contributed equally to this work.

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Citation:
Ye ZW, Fan Y, Tang K, Ong CP, Luo C, Chung HL, Leong TL, Liang R, Lui WY, Zhou R, Cheng Y, Lu L, Cheung PHH, Chan JFW, Chen Z, Yuen KY, Yuan S, To KKW, Jin DY. Cross-variant protection against SARS-CoV-2 infection in hamsters immunized with monovalent and bivalent inactivated vaccines. Int J Biol Sci 2022; 18(12):4781-4791. doi:10.7150/ijbs.72109. Available from https://www.ijbs.com/v18p4781.htm

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Abstract

Graphic abstract

Rapid development and successful use of vaccines against SARS-CoV-2 might hold the key to curb the ongoing pandemic of COVID-19. Emergence of vaccine-evasive SARS-CoV-2 variants of concern (VOCs) has posed a new challenge to vaccine design and development. One urgent need is to determine what types of variant-specific and bivalent vaccines should be developed. Here, we compared homotypic and heterotypic protection against SARS-CoV-2 infection of hamsters with monovalent and bivalent whole-virion inactivated vaccines derived from representative VOCs. In addition to the ancestral SARS-CoV-2 Wuhan strain, Delta (B.1.617.2; δ) and Theta (P.3; θ) variants were used in vaccine preparation. Additional VOCs including Omicron (B.1.1.529) and Alpha (B.1.1.7) variants were employed in the challenge experiment. Consistent with previous findings, Omicron variant exhibited the highest degree of immune evasion, rendering all different forms of inactivated vaccines substantially less efficacious. Notably, monovalent and bivalent Delta variant-specific inactivated vaccines provided optimal protection against challenge with Delta variant. Yet, some cross-variant protection against Omicron and Alpha variants was seen with all monovalent and bivalent inactivated vaccines tested. Taken together, our findings support the notion that an optimal next-generation inactivated vaccine against SARS-CoV-2 should contain the predominant VOC in circulation. Further investigations are underway to test whether a bivalent vaccine for Delta and Omicron variants can serve this purpose.

Keywords: COVID-19, Inactivated vaccine, Neutralizing antibodies, Immune protection, SARS-CoV-2 variants of concern