Emerging SARS-CoV-2 B.1.621/Mu variant is prominently resistant to inactivated vaccine-elicited antibodies
Xiaochun Xie, 中国科学院昆明动物研究所中国科学院动物模型与人类疾病机理重点实验室, 中国科学院昆明动物研究所-香港中文大学生物资源与疾病分子机理联合实验室, 云南 昆明 650201, 中国, Jian-Bao Han, Guanqin Ma, Xiaoli Feng, Xiaohong Li, Qing‐Cui Zou, Zhonghua Deng, Jianxiong Zeng, 中国科学院昆明动物研究所国家昆明高等级生物安全灵长类动物实验中心, 生物安全大科学中心, 云南 昆明 650107, 中国, 中国科学院昆明动物研究所国家非人灵长类实验动物资源库, 模式动物表型与遗传研究国家重大科技基础设施(灵长类设施), 云南 昆明 650107, 中国
Abstract
Although it first appeared almost two years ago, the COVID-19 pandemic continues to have an impact on a global scale, in part due to newly emerging SARS-CoV-2 variants such as Delta and Lambda. The B.1.621 variant, first identified in Colombia in January 2021, was classified as a variant of interest (VOI) and designated as Mu by the World Health Organization (WHO) in August 2021. However, its infectivity and resistance to neutralizing antibodies remain largely unknown. Here, in comparison to Delta, the Mu variant showed an unexpectedly enhanced immune resistance to inactivated vaccine-elicited antibodies. Nevertheless, Mu demonstrated less infectivity than Delta, implying a biological trade-off between viral transmission and immune escape. This study strongly calls for urgent evaluation of the protective efficacy of current COVID-19 vaccines against the Mu variant.