AUTHOR=Jin Bo , Oyama Rieko , Tabe Yoko , Tsuchiya Koji , Hando Tetsuya , Wakita Mitsuru , Yan Yan , Saita Mizue , Takei Satomi , Horiuchi Yuki , Miida Takashi , Naito Toshio , Takahashi Kazuhisa , Ogawa Hideoki TITLE=Investigation of the individual genetic evolution of SARS-CoV-2 in a small cluster during the rapid spread of the BF.5 lineage in Tokyo, Japan JOURNAL=Frontiers in Microbiology VOLUME=Volume 14 - 2023 YEAR=2023 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1229234 DOI=10.3389/fmicb.2023.1229234 ISSN=1664-302X ABSTRACT=Monitoring genetic mutations is critical since SARS-CoV-2 continues to spread in some areas, posing potential healthcare risks. Mutations that occur during viral replication can be selectively retained, leading to changes in infectivity and pathogenicity. Genetic mutations that occur through cluster infections can contribute to the spread of the virus within the cluster and could potentially influence the virus' evolution in other regions. Accurately understanding the quality of genetic mutations is also crucial for the development of vaccines and treatments. However, despite the importance of the virus genome mutation process, few studies have investigated this aspect. In this research, we conducted a genomic sequence analysis of a small Omicron BA.5 lineage cluster. All members of this cluster recovered without requiring any treatment. Our findings reveal that this cluster shared some common mutations and was classified as the Omicron variant BF.5. We also identified some lowfrequency mutations. This cluster occurred during a one-week period between June and July 2021, when the Omicron sub-lineage BF.5 was spreading in Tokyo, Japan, alongside the dominant BA.5 sub-lineage. Furthermore, we have reported on the location of genetic mutations that occurred in each individual of this cluster and discussed their potential functional implications in relation to the corresponding genes.