Wakaki Kami: Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus. 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Takeshi Kinjo: Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus. 207 Uehara, Nishihara, Okinawa 903-0215, Japan. Electronic address: t_kinjo@med.u-ryukyu.ac.jp.
Wakako Arakaki: Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus. 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Hiroya Oki: Department of Infection Metagenomics, Genome Information Research Center, Research Institute for Microbial Diseases. 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Daisuke Motooka: Department of Infection Metagenomics, Genome Information Research Center, Research Institute for Microbial Diseases. 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Shota Nakamura: Department of Infection Metagenomics, Genome Information Research Center, Research Institute for Microbial Diseases. 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Jiro Fujita: Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus. 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
BACKGROUND: . The emergence of SARS-CoV-2 variants has caused an unexpected rebound globally. The World Health Organization has listed three variants (B.1.1.7, B.1.351, and P.1) as variants of concern. To understand the epidemiology and thereby plan appropriate safety measures, differential identification of the variants is indeed critical. OBJECTIVES: . Although whole-genome sequencing is the gold standard for variant identification, it is time-consuming and relatively expensive. Therefore, a rapid, easy, and cost-effective platform targeting multiple regions of the genome is required. Here, we assessed the usefulness of the Novaplex™ SARS-CoV-2 Variants I Assay kit in identifying mutations in the variants. STUDY DESIGN: . We retrospectively examined 30 stored nasal swabs from COVID-19-positive patients tested between November 2020 and March 2021. RNA extracted from these swabs was subjected to the commercial kit and real-time reverse transcription-PCR was performed. To determine the genome sequences of SARS-CoV-2 in the collected samples and deduce the consensus sequences among the identified variants, genome sequencing libraries were prepared and mapped to the reference genome. RESULTS: . Four of the tested samples were determined as variants. Of them, two harbored both H69/V70 deletion and N501Y substitution, whereas two harbored E484K substitution alone. CONCLUSIONS: . The variant with E484K substitution alone ("R.1") has been now categorized as a variant of interest in Japan. Additionally, the kit-based assay was found to be feasible, convenient, and user-friendly in identifying the abovementioned mutations with a turnaround time of only 2 h.
