SARS-CoV-2 Gamma variant

The Gamma variant (P.1) was one of the variants of SARS-CoV-2, the virus that causes COVID-19. This variant of SARS-CoV-2 has been named lineage P.1 and has 17 amino acid substitutions, ten of which in its spike protein, including these three designated to be of particular concern: N501Y, E484K and K417T. This variant of SARS-CoV-2 was first detected by the National Institute of Infectious Diseases (NIID) of Japan, on 6 January 2021 in four people who had arrived in Tokyo having visited Amazonas, Brazil, four days earlier. It was subsequently declared to be in circulation in Brazil. Under the simplified naming scheme proposed by the World Health Organization, P.1 has been labeled Gamma variant, and is currently considered a variant of concern.

Gamma caused widespread infection in early 2021 in the city of Manaus, the capital of Amazonas, although the city had already experienced widespread infection in May 2020, with a study indicating high seroprevalence of antibodies for SARS-CoV-2. A research article published in Science Journal indicate that P.1 infected people have a greater chance of transmissibility and death than B.1.1.28 infected ones.

The Gamma variant comprises the two distinct subvariants 28-AM-1 and 28-AM-2, which both carry the K417T, E484K, N501Y mutations, and which both developed independently of each other within the same Brazilian Amazonas region.

Gamma is notably different from the Zeta variant (lineage P.2) which also circulated strongly in Brazil. In particular, Zeta only carries the E484K mutation and has neither of the other two mutations of concern, N501Y and K417T.