Disease Waves of SARS-CoV-2 in Iran Closely Mirror Global Pandemic Trends.

BACKGROUND

Complete SARS-CoV-2 genome sequencing in the early phase of the outbreak in Iran showed two independent viral entries. Subsequently, as part of a genome surveillance project, we aimed to characterize the genetic diversity of SARS-CoV-2 in Iran over one year after emerging.

METHODS

We provided 319 SARS-CoV-2 whole-genome sequences used to monitor circulating lineages in March 2020-May 2021 time interval.

RESULTS

The temporal dynamics of major SARS-CoV-2 clades/lineages circulating in Iran is comparable to the global perspective and represent the 19A clade (B.4) dominating the first disease wave, followed by 20A (B.1.36), 20B (B.1.1.413), 20I (B.1.1.7), leading the second, third and fourth waves, respectively. We observed a mixture of circulating B.1.36, B.1.1.413, B.1.1.7 lineages in winter 2021, paralleled in a fading manner for B.1.36/B.1.1.413 and a growing rise for B.1.1.7, prompting the fourth outbreak. Entry of the Delta variant, leading to the fifth disease wave in summer 2021, was detected in April 2021. This study highlights three lineages as hallmarks of the SARS-CoV-2 outbreak in Iran; B4, dominating early periods of the epidemic, B.1.1.413 (B.1.1 with the combination of [D138Y-S477N-D614G] spike mutations) as a characterizing lineage in Iran, and the co-occurrence of [I100T-L699I] spike mutations in half of B.1.1.7 sequences mediating the fourth peak. It also designates the renowned combination of G and GR clades' mutations as the top recurrent mutations.

CONCLUSION

In brief, we provided a real-time and comprehensive picture of the SARS-CoV-2 genetic diversity in Iran and shed light on the SARS-CoV-2 transmission and circulation on the regional scale.