emergence of SARS-CoV-2 variants; public health concerns and risks
emergence of SARS-CoV-2 variants; public health concerns and risks
Sobhan Sadeghiyan,1,*Seyed Reza Mohebbi,2Seyed Masoud Hosseini,3Shabnam Kazemian,4Mahsa Saeedi Niasar,5Hamid Asadzadeh Aghdaea,6
1. Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2. Research Center for Gastroenterology and Liver Diseases, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3. Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran 4. Research Center for Gastroenterology and Liver Diseases, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 5. Research Center for Gastroenterology and Liver Diseases, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Introduction: The first case of a new coronavirus that cause severe acute respiratory syndrome was observed in December 2019 in Wuhan, China. From December 2019 until 24 September 2021, there have been more than 230 million confirmed cases of COVID-19, including approximately 4,700,000 deaths. The first submitted sequence of SARS-CoV-2 was collected from a Wuhan market worker on 26 December 2019. In first days of 2020, the sequence's accession number in the GenBank has been published (NC 045512). Due to the Covid-19 pandemic, several studies about sars-cov-2 mutations and phylogenetic analyses have been performed. WHO watch carefully variants and classify them to variant of interest (VOI), variant of concern (VOC), and Variant of High Consequence (VOHC). VOI is a variant with distinct genetic mutations that have been linked to receptor binding affinity alteration, decrease in antibody efficacy, and neutralization property through past infection or immune induction by vaccination, probable diagnostic failure, or escalation in pathogenesis, disease severity, or transmissibility. It can be classified as VOC if there is evidence of a boost in disease severity, transmissibility, neutralizing antibodies inefficacy, in vaccinated or previously infected individuals, or detection inability of diagnostic assays. If there are clear clinical and research evidence on decrease in effectiveness of prevention measures or medical countermeasures in comparison to past variants in society, it can be considered VOHC.
Methods: The Elsevier databases were used to conduct a targeted literature search. We searched for “coronavirus” and each of the following terms or phrases separately and in combination: “SARS-CoV-2,” “mutation,” “genome,” “variant,” and “genomic changes.”
Results: Previous studies revealed more than 5000 various variants comprised variants with synonymous mutations, non-coding regions mutations, frame-shift deletions, in-frame insertions, non-coding insertions, stop-gained variants, in-frame deletions, non-coding deletions, and missense mutations. D614G, L84S, G392D, L3606F, D448 deletion are significant changes in the virus genome.
Up to now, the variants of concern by WHO included: Alpha(GRY clade), Beta(GH clade), Gamma(GR clade), Delta(G clade). Recently, the Delta variant (B.1.617.2) was found in India and after a while became the predominant variant globally. T19R, E156G, del157/158, L452R, T478K, D614G, P681R, P681R, and D950N mutations are the characteristic mutations of the delta variant.
Conclusion: Research findings revealed that Delta variant has significantly higher transmissibility properties and also studies showed that vaccine-induced immune response has a lower efficacy with regard to Delta. In addition, two variants of interest, Lambda (Gr clade) and Mu (GH clade) were found in Peru and Colombia, respectively that should be monitored more carefully.