“There are more than 7 Covid-19 genetic lines circulating in the world. The most widespread in Bulgaria is the line which is predominant in Europe and USA. There are 3 more genetic lines circulating in the country. One of them is the original one from Wuhan,” Assoc. Prof. Ivan Ivanov, head of the National Reference Laboratory “Control and Monitoring of Antimicrobial Resistance” said for BNT.

Virologist Assoc. Prof. Ivailo Alexiev quotes a study according to which some coronavirus strains build up immunity, whereas others do not. He does not expect the circulation of different Covid-19 mutations to change with every passing year.