The US has recorded more than 13,000 cases of coronavirus variants, according to the latest data of the Centers for Disease Control and Prevention (CDC).
Among the total of 13,052 variants cases reported by the CDC as of Friday, 12,505 cases were caused by the variant known as B.1.1.7, which was originally detected in Britain, reports Xinhua news agency.
There were 323 cases of a new strain initially discovered in South Africa, called B.1.351, and 224 cases of the P.1 strain first discovered in Brazil.
In addition, the B.1.427 and B.1.429 variants, two coronavirus strains first detected in the California, are also being closely monitored by the CDC.
The five coronavirus strains are currently classified by the CDC as “variants of concern”, as evidence shows an increase in their transmissibility, increased hospitalizations or deaths, reduced effectiveness of treatments or vaccines, and diagnostic detection failures.