A very recent research paper by researchers in Peru describes a new variant of the SARS-CoV-2 coronavirus known as the Lambda variant (C.37). The Lambda variant was first reported in Lima, Peru in December 2020 and, since April 2021, nearly all coronavirus infections in the country are caused by it. The Lambda variant has seven mutations in the spike gene and one deletion in the ORF1a gene. Deletion of the ORF1a gene has been observed in other variants of interest, including Alpha (B.1.1.7), Beta (B.1351), and Gamma (P.1). The range is currently dominant in Central and South America, but Lambda’s high transmission rate may soon surpass it. The study authors stated that the expansion of C.37 occurred in South America in the presence of hundreds of circulating lines and Alpha and Gamma VOCs, suggesting greater transmissibility of this line. However, further epidemiological data and analyzes are needed to evaluate its transmission, virulence and immune escape properties.
Vaccines can help neutralize the Lambda variant. However, vaccination rates in South America continue to be low for various reasons. Increased vaccination in the country could prevent Lambda from becoming a variant of concern. Since May 31, 2021, Peru has seen 0.54% of its country succumb to SARS-CoV-2, the highest rate of deaths from COVID-19 globally compared to the population. Genomic surveillance is routinely performed to examine SARS-CoV-2 lineages in the population. The first record for the Lambda variant was in November 2020 in Argentina. In December 2020, genomic surveillance revealed that the Lambda variant comprised 0.5% of infections in Lima, Peru. Genomic surveillance showed a deeply branched sub-lineage of B.1.1.1 (Lambda). Since its initial survey, the prevalence of the Lambda variant in Peru has increased over time: 20.5% in January, 36.4% in February, 79.2% in March and 96.6% in April 2021.As Lambda increased, other coronaviruses declined over time. In the last four months, the Alpha variant made up 0.5% of the Peruvian population while the Gamma variant 1.2%.
By June 19, 2021, there were 1,771 sequences related to the Lambda variant in 25 countries, including Chile, the United States, Peru, Argentina, Germany, Mexico, Spain and Ecuador. Scientists believe that the emergence of this lineage in Peru and its export to other countries is a current hypothesis given its previous detection and the nearly 100% increase in public sequences by April. So is there to worry about the potential ineffectiveness of vaccines and antibodies? It doesn’t seem to judge from the preliminary results of a team from New York University’s Grossman School of Medicine, which also suggests that the monoclonal antibody cocktail should be effective against variant C.37. Researchers tested the infectivity and susceptibility of the pseudotyped lentivirus with the spike protein C.37 to neutralization by convalescent sera, vaccine-elicited antibodies and Regeneron REGN10933 and REGN10987 monoclonal antibodies. Analysis of sera from convalescent patients who had been infected prior to the appearance of the SARS-CoV-2 variants, showed that C.37 was 3.3 times more resistant to neutralization than the D614G spike mutation.
Similarly, serum analysis of individuals who had been immunized with the Pfizer vaccine or the Moderna vaccine showed that the C.37 spike virus was approximately 3 and 2.3 times more resistant to neutralization, respectively. Finally, it seems official that one of the variants that gives interest (VOI) has become of concern (VOC) turns out to be the so-called Epsilon variant, even if the one that worries most is the Delta, that is the former Indian variant, which has caused the infections to surge again throughout Europe and also in the United States. According to unconfirmed speculations, the Epsilon variant could reduce the efficacy of the Pfizer vaccine by as much as 15%. So the univocal answer of the experts is that of prevention: not one, but both doses of the vaccine must be done and there would be no time to waste. Although the variant is apparently no more lethal, it is certainly more contagious and the fact that it compromises the vaccine potency is a more than justified alarm bell.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
McCallum M et al. Science. 2021 Jul 1:eabi7994.
Shen X et al. New Engl J Med 2021; 384:2352-54.
Tsukayama et al. medRxiv 2021 Jun 26: 21259487.