Analysis: Why the Lambda coronavirus variant, detected in South America, is now “of interest”

RIO DE JANEIRO, BRAZIL – It was first detected in Peru, and then in Argentina, Chile and Uruguay. It is currently present in Covid-19 patients in 29 countries in 5 regions of the world. In Argentina, its impact on potential re-infection and on vaccinated patients is being studied.

The “Andean” coronavirus variant has now been officially named Lambda by the World Health Organization (W.H.O.) and classified as “of interest.” This variant had been reported in preliminary studies last August by researchers in Peru and was later detected in Argentina.

Over the past three months, it has been more frequently detected in sequenced samples of Covid-19 patients in most South American countries, while cases have increased in the region. Scientists are now asking: Did the Lambda variant contribute to the second wave of the pandemic in South America?

The emergence of coronavirus mutations is a natural and expected event in the evolutionary process of viruses. These changes may bring advantages, and the virus may have a greater ability to penetrate cells and then replicate, trying to escape the natural or vaccine-mediated immune response. There are also mutations of no interest or concern.

The 7 keys to understanding the Lambda variant

1- When it was detected

According to the W.H.O., the Lambda variant, which is technically called C.37, was first reported in Peru in August 2020. There were also reports of the C.37 in November by researchers from ANLIS/Malbrán Institute, under the Argentine Ministry of Health. Since last January, the Lambda began to be detected in Covid-19 patient sample reports by Proyecto País, part of Argentina’s Ministry of Science, Technology and Innovation.

In May, Peru’s Minister of Health Óscar Ugarte reported that the C.37 variant was present in 80% of all samples analyzed in Lima. He suggested that “it could be behind the peak of the second wave of Covid-19.″ Last March, Lambda was found in over 40% of patient samples in Lima.

2- Why has the W.H.O. classified it as a “variant of concern”?

The organization has been updating the classification system of the coronavirus variants as they emerge in the world. Detected variants are considered by W.H.O. experts in cooperation with partners, expert networks, national authorities, institutions and researchers engaged in studying and assessing the evolution of the SARS-CoV-2 virus since January 2020.

The emergence of variants that posed an increased risk to global public health in late 2020 prompted the specific categories of “variant of interest” and “variant of concern” to begin to be used to prioritize global monitoring and research and to guide the response to the Covid-19 pandemic.

The Lambda is currently “of interest” because there have been reports of its increased frequency in Covid-19 patient samples in South American countries, such as Argentina, Chile, and Peru. But it has also now been detected in 29 countries. This suggests that this coronavirus variant has managed to spread to different regions of the world.

3- Why is the “Andean” variant now called Lambda?

As of June, the W.H.O. began to use Greek letters to designate variants. The variant first detected in the United Kingdom in September last year was classified as Alpha. The South African variant is named Beta and the Indian variant as Delta. The P.1 variant, previously referred to as the Manaus variant because it was detected in the Brazilian city, was renamed Gamma. The scientific denomination continued to be used, but the name was changed to Greek letters to prevent variants of interest or concern from being associated with city and country populations.

The Indian government had complained about the naming of the B.1.617.2 variant, first detected in India last October, as the “Indian variant”. Now, it is called Delta, and over the past few weeks it has attracted worldwide attention because it is estimated to be behind the increase in cases in England. “No country should be stigmatized for detecting and reporting variants,” said Maria Van Kerkhove, W.H.O.’s Covid-19 technical coordinator.

In the case of the Andean variant, it was named Lambda, the 11th letter of the Greek alphabet.

4- Why is the Lambda a “variant of interest”?

With Lambda, there are now 7 variants of interest identified by the W.H.O. The Lambda variant was associated with significant rates of community transmission in multiple countries, the W.H.O. stated in its justification for classifying it as a “variant of interest”. By June 15, 2021, over 1,730 sequences from 29 countries in five regions had been uploaded to the GISAID platform. “High prevalence has been particularly observed in South America,” experts acknowledged.

Authorities in Peru reported that 81% of Covid-19 cases sequenced since April 2021 were associated with Lambda. Argentina reported an increase in Lambda’s prevalence since the third week of February 2021, and between April 2 and May 19, 2021, the variant accounted for 37% of Covid-19 cases sequenced. But in the Buenos Aires Metropolitan Area, the Lambda variant was detected in over 60% of sequenced samples. In Chile, Lambda’s prevalence has increased over time, representing 32% of the sequenced cases reported in the past 60 days.

The Lambda variant has mutations that have “putative phenotypic implications, such as potentially increased transmissibility or possible increased resistance to neutralizing antibodies,” they noted in the weekly report. But so far “there is limited evidence on the full extent of the impact associated with these genomic changes, and more robust studies on phenotypic impacts are required to better understand the impact on countermeasures and to control spread. More studies are also needed to confirm the continued efficacy of vaccines.”

5- The Lambda variant could impact the surge in second wave cases

It is a possibility that the Lambda variant is more transmissible and has had an impact on the rise of cases in countries such as Peru, Argentina and Chile, which led to overwhelmed hospitals. It is still a hypothesis to be investigated. However, the coordinator of Proyecto País, Mariana Viegas, a researcher at the Conicet and the Ricardo Gutiérrez Children’s Hospital in Buenos Aires, said “We have observed that in the city of Buenos Aires and the suburbs the frequency of the Lambda variant has been increasing every week since we detected it in January. At first, the frequency was low, and then it began to increase, even in the presence of co-circulation of the Gamma and Alpha variants. That struck us: even in the past few weeks the Lambda has increased while the Alpha has decreased.”

According to the scientist, it is possible that the Lambda variant has impacted the increase in cases of the latter. “If we think that the Gamma and Alpha variants are now considered to be more transmissible, and that Lambda increases at the same time as the Gamma and at the expense of the Alpha, it is possible that it could be associated with the increase in Covid-19 cases in recent months,” said Dr. Viegas. “A similar situation is occurring in Peru and Chile.”

6- What steps will be taken now to address the Lambda’s health impact?

“As it has been declared a variant of interest in the world, now the focus will be on Lambda and there will be more groups of scientists working on its characteristics and its impact,” said Viegas. “In Proyecto País, in partnership with the Institute of Biomedical Research in Retrovirus and AIDS, of the Buenos Aires University and the Conicet, we are now studying the neutralization of the Lambda variant with sera from the first wave of the pandemic, during the past year, and from vaccinated people,” she said.

It will also be necessary to study whether the variant sequence in its “Spike” protein, which makes it easier for the virus to penetrate the cells of the human organism, has any implication in transmission, and comparisons will be made in terms of severity and hospitalizations.

7- Can the population take action to avert the impact of variants such as Lambda?

Although it was expected that coronavirus variants would emerge, both W.H.O. and national health authorities caution that the more the virus circulates in communities, the more chances it will have to evolve. Therefore, each person can contribute by observing all preventive measures, such as the use of masks, frequent hand washing, permanent cross-ventilation, keeping a 2-meter distance, and refraining from social gatherings with non-cohabitants in enclosed places. Along with vaccination, these types of measures, called “non-pharmacological interventions,” continue to be fundamental to curb the spread of the coronavirus. They should also be taken into account in hospitals.

Source: Infobae