COVID-19 is caused by SARS-CoV-2, several virulent variants of which have emerged since 2019. More than 529 million people have been infected, and at least 6 million have died. Our aim was to develop a fast, accurate, low-cost method for detecting and identifying newly emerging variants of concern (VOCs) that could pose a global threat. The 341-bp DNA sequence of a specific region of the SARS-CoV-2’s spike protein was amplified by a one-step PCR on RNA samples from 46 patients. The product was sequenced using next-generation sequencing (NGS). DNA sequences from seven genomes, the original Wuhan isolate and six different representative variants obtained from the GISAID website, were used as references. Complete whole-genome sequences from local isolates were also obtained from the GISAID website, and their RNA was used for comparison. We used an amplicon-based NGS method (termed VOC-NGS) for genotyping and successfully identified all 46 samples. Fifteen (32.6%) were like the original isolate. Twenty-seven were VOCs: nine (19.5%) Alpha, eight (19%) Delta, six (14%) Beta, and four (8.7%) Omicron. Two were variants of interest (VOI): one (2%) Kappa and one (2%) Zeta. Two samples were mixtures of two variants, one of Alpha and Beta and one of Alpha and Delta. The Spearman correlation between whole-genome sequencing (WGS) and VOC-NGS was significant (P, 0.001) with perfect agreement (Kappa = 0.916) for 36/38 (94.7%) samples with VOC-NGS detecting all the known VOCs. Genotyping by VOC-NGS enables rapid screening of high-throughput clinical samples that includes the identification of VOCs and mixtures of variants, at lower cost than WGS. IMPORTANCE The manuscript described SARS-Cov-2 genotyping by VOC-NGS, which presents an ideal balance of accuracy, rapidity, and cost for detecting and globally tracking VOCs and some VOI of SARS-CoV-2. A large number of clinical samples can be tested together. Rapid introduction of new mutations at a specific site of the spike protein necessitates efficient strain detection and identification to enable choice of treatment and the application of vaccination, as well as planning public health policy.
Bibliographical noteFunding Information:
S.A. is the recipient of the Jacob and Lena Joels memorial fund senior lectureship. H.G.B. is the recipient of the Manja Gideon Foundation scholarship in Switzerland and the Levtzion scholarship from the Israel Council for Higher Education.
Copyright © 2022 Nasereddin et al.
- variants of concern (VOC)
- variants of interest (VOI)