PT  - JOURNAL ARTICLE
AU  - Keiya Uriu
AU  - Izumi Kimura
AU  - Kotaro Shirakawa
AU  - Akifumi Takaori-Kondo
AU  - Taka-aki Nakada
AU  - Atsushi Kaneda
AU  - The Genotype to Phenotype Japan (G2P-Japan) Consortium
AU  - So Nakagawa
AU  - Kei Sato
TI  - Ineffective neutralization of the SARS-CoV-2 Mu variant by convalescent and vaccine sera
AID  - 10.1101/2021.09.06.459005
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.09.06.459005
4099  - http://biorxiv.org/content/early/2021/09/07/2021.09.06.459005.short
4100  - http://biorxiv.org/content/early/2021/09/07/2021.09.06.459005.full
AB  - On August 30, 2021, the WHO classified the SARS-CoV-2 Mu variant (B.1.621 lineage) as a new variant of interest. The WHO defines “comparative assessment of virus characteristics and public health risks” as primary action in response to the emergence of new SARS-CoV-2 variants. Here, we demonstrate that the Mu variant is highly resistant to sera from COVID-19 convalescents and BNT162b2-vaccinated individuals. Direct comparison of different SARS-CoV-2 spike proteins revealed that Mu spike is more resistant to serum-mediated neutralization than all other currently recognized variants of interest (VOI) and concern (VOC). This includes the Beta variant (B.1.351) that has been suggested to represent the most resistant variant to convalescent and vaccinated sera to date (e.g., Collier et al, Nature, 2021; Wang et al, Nature, 2021). Since breakthrough infection by newly emerging variants is a major concern during the current COVID-19 pandemic (Bergwerk et al., NEJM, 2021), we believe that our findings are of significant public health interest. Our results will help to better assess the risk posed by the Mu variant for vaccinated, previously infected and naïve populations.Competing Interest StatementThe authors have declared no competing interest.