Monitoring of SARS-CoV-2 B.1.1.7 variant early-phase spreading in South-Moravian Region in the Czech Republic and evaluation of its pathogenicity

SARS-CoV-2 emerged in Wuhan, China, in December 2019. Starting in January 2020, over a period of several months, the initial virus (Wuhan-Hu-1/2019; Wu et al. 2020) diverged in a descendant strain carrying D614G amino acid mutation in spike protein. By summer 2020 this novel coronavirus (nCoV) became the most dominant form of the virus circulating worldwide and raised serious international concern. Currently (April 2021), there are 3598 subsequent PANGO branched lineages recognized that carry numerous mutations. To date, the most emerging lineages of SARS-CoV-2 worldwide include B.1.1.7 lineage with a frequency of 48% followed by several dozens of others with frequencies 7.5% or less, such as B.1.351, B.1.1.28, B.1.2, B.1.1.519, P.1, R.1, etc. (www.nextrain.org, Centers for Disease Control and Prevention; CDC 2020 www.cdc.gov). In this study, we monitored the spreading of B.1.1.7 lineage from the early phase of its appearance until it became predominant in the South-Moravian region of the Czech Republic. We measured significantly associated clinical marker (Ct; cycle threshold) correlating with viral load in B.1.1.7 lineage. Interestingly, we found that the spreading of B.1.1.7 strain was associated with a shift in patients average age, as compared to the former predominant lineage. Finally, we calculated the impact of the B.1.1.7 lineage on hospitalization and case fatality of the patients on the intensive care unit in the central South-Moravian faculty hospital.