The lambda form of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is described in a recent study article by Peruvian researchers (C.37). The Lambda variety was initially discovered in Lima, Peru in December 2020 and since April 2021, it is responsible for almost all coronavirus infections in the country.
The lambda variant contains seven spike gene mutations and one ORF1a gene deletion. Other variations of concern, such as alpha (b.1.1.7), beta (b.1351), and gamma, have the ORF1a gene deleted (p.1).
In Central and South America, gamma now dominates, but lambda’s high transmission rate may soon surpass it. The study authors write:
“Expansion of C.37 has occurred in South America in the presence of hundreds of circulating lineages and VOCs Alpha and Gamma, suggesting increased transmissibility of this lineage. However, additional epidemiological data and analyses are needed to assess its transmission, virulence, and immune escape properties.”
Vaccines can help neutralize the lambda variant. However, vaccination rates in South America are low for several reasons. Increased vaccination in the country can prevent lambda from becoming a serious disease.
Prior to peer review, the paper “Emergence of SARS-CoV-2 variant lambda (C.37) in South America” was recently released on the preprint medRxiv* service.
Peru has seen 0.54 percent of its population succumb to SARS-CoV-2 since May 31, 2021, the world’s highest incidence of COVID-19 fatalities per capita.
Genomic surveillance is carried out on a regular basis to check the SARS-CoV-2 lineage in the community. For this research, the Peruvian genome was examined at the Universidad Peruna Cayetano Heredia and Instituto Nacional de Salud.
The genome was compared to hundreds of SARS-CoV-2 genomes sequenced in Argentina and Chile. GISAID was also used to download the SARS-CoV-2 genomic assemblies for Peru. GISAID includes 1,424 genomic sequences from 64 circulating lineages in Peru as of June 2021.
Formation and spread of Lambda
The lambda variation was first discovered in Argentina in November 2020. In Lima, Peru, genomic surveillance indicated that lambda variation was found in 0.5 percent of infections in December 2020. Genomically, B.1.1 has a deeply branching subline. Monitor (lambda).
The prevalence of the lambda variant in Peru has increased steadily since its discovery – 20.5 percent in January, 36.4 percent in February, 79.2 percent in March and 96.6 percent in April 2021.
Other SARS-CoV-2 strains decreased over time as lambda increased. The alpha variation accounted for 0.5 percent of the Peruvian population over the past four months, while the gamma variant accounted for 1.2 percent.
Lambda detection in other South American countries
As of June 19, 2021, there were 1,771 sequences associated with lambda variation in 25 countries, including Chile, the United States, Peru, Argentina, Germany, Mexico, Spain, and Ecuador.
COVID-19 cases linked to lambda variations have increased in Chile and Argentina. Since April 2021, the variation has made up 33% of the genomic sequences of Chile and 13% of Argentina.