According to a report released by the World Health Organization (WHO) on Thursday, four SARS-CoV-2 variants are responsible for the widespread circulation of the infection worldwide, CGTN reported.
The first strain of the virus had D614G substitution in the gene encoding the spike protein. This virus was in circulation between January – February 2020. Its mutation was reported in June wherein it became more contagious but less severe than the previous strain.
The second variant – Cluster 5 – was detected in Denmark’s mink breeding farms in late January or early February 2020. This type of virus decreases virus neutralisation in humans, which could potentially reduce the extent and duration of immune protection following natural infection or vaccination. The report said this variant does not appear to have spread widely.
The third variant was reported last year on December 14 in the United Kingdom. The new variant – SARS-CoV-2 VOC 202012/01 – first appeared in southeast England.
Researchers in the UK suggested that though the transmissibility of the virus is relatively higher than other strains, it does not, however, cause a change in disease severity.
The WHO report said that VOC-202012/01 had been reported in 31 other countries/territories/areas in five of the six WHO regions as of December 30, 2020.
The fourth variant – 501Y.V2 – was reported on December 18, in South Africa. The variant is associated with a higher viral load, suggesting a potential for increased contagion.
In November, South African health authorities found that this new variant has mostly replaced other SARS-CoV-2 viruses circulating in the Eastern Cape, Western Cape KwaZulu-Natal provinces.