So far, five variants of coronavirus have been labeled as variants of concern:
Alpha, Beta, Gamma, Delta, and Omicron.
The Alpha variant, B.1.1.7, was first found in the United Kingdom in September 2020, as per WHO. The Beta variant, B.1.351, was found in South Africa in May 2020. The next highly transmissible variant, Gamma, P.1, was found in Brazil in November 2020.
“These three ‘variants of concern’ share some mutations, particularly in key regions of the spike protein involved in the host-cell ACE receptors that the virus uses to enter cells. They also carried mutations similar or identical to those spotted in SARS- CoV-2 in people with compromised immune systems whose infections lasted for months,” says a Nature article.
The fourth variant, Delta, B.1.617.2, or the super-Alpha, as researchers call it, was identified in India in October 2020. Epidemiologists say it was 60% more transmissible than the alpha variant. “Compared with other variants, including Alpha, Delta multiplies faster and to higher levels in the airways of infected individuals, potentially outpacing initial immune responses against the virus,” the article says.
The Omicron, B.1.1.529, variant was traced in November 2021. Compared with other variants, Omicron contains more mutations, in the spike that recognizes host cells, thus accounting for its transmissibility.
The coronavirus variants which are variants of interest as per WHO are Lambda and Mu.