Explainer: What is the Lambda coronavirus variant?

The Lambda variant has spread to 28 countries but it is not considered a variant of concern. Here’s what we know so far.

The Lambda variant of the coronavirus was first detected in Peru in December last year [File: Claudia Morales/Reuters]

Since the COVID-19 pandemic began, the virus that causes the disease, SARS-CoV-2, has mutated multiple times, with some strains being more infectious and deadlier than others.

Currently, the World Health Organization (WHO) has classified four of those mutations as variants of concern: Alpha, Beta, Gamma and Delta.

Four others – Eta, Iota, Kappa and Lambda – have been designated as variants of interest, and in recent weeks the rapid spread of the Lambda strain, first detected in Peru, has caught the attention of various experts.

Lambda is currently the dominant variant in the Andean nation, which has the highest per capita coronavirus death rate in the world, while it has also spread to at least 28 other countries including Argentina, Brazil, Colombia, Ecuador, and the United Kingdom.

Here is what we know so far:

Where and when was it first detected?

The Lambda variant was first detected in Peru last December. It is a variation of the novel coronavirus that was first recorded in the country in August 2020.

The exact origins of the Lambda variant, which was previously known as the Andean strain, remain unclear, but scientists say it first emerged in South America.

Over the last three months, Lambda has grown to represent 80 percent of all cases in Peru, according to the country’s National Institute of Health.

“When we found it, it did not attract much attention,” said Pablo Tsukayama, a doctor in molecular microbiology at Cayetano Heredia University in Lima and one of the people who documented Lambda’s emergence.

“But we continued processing samples, and by March, it was in 50 percent of the samples in Lima. By April, it was in 80 percent of the samples in Peru,” Tsukayama told Al Jazeera. “That jump from one to 50 percent is an early indicator of a more transmissible variant,” he added.

According to Tsukayama, the Lambda strain did not initially cause alarm because new strains are common in places with high infection rates. Latin America and the Caribbean, while home to eight percent of the global population, account for 20 percent of the world’s COVID cases, according to a June 24 report by the US-based Congressional Research Service.

“But around May, Chile and Peru requested the WHO to consider the variant and to add it to the list of variants of interest. In mid-June, the WHO accepted and labelled it as Lambda,” he said.

Where has it spread?

According to data from the Global Initiative on Sharing All Influenza Data (GISAID), a platform onto which countries upload their COVID-19 viral sequences, the Lambda strain has already reached 28 countries.

That includes Brazil, Spain, the Netherlands, Aruba, Belgium, France, Portugal and the United States.

What are the strain’s characteristics?

Recent research on the Lambda strain has registered several mutations in its spike protein, the part of the virus that makes contact with human cells, binds to them, and then infects them.

The mutation observed in the spike protein might be the reason for its “increased transmissibility… and it could provide a reduction of protection by current vaccines”, according to a study released in July by a team from New York University’s Grossman School of Medicine and released on the medical website bioRxiv ahead of peer review.

According to virologist Ricardo Soto-Rifo of the University of Chile’s Institute of Biomedical Sciences, one of the mutations labelled as L452Q was similar to a mutation also shown in the Delta variant that is believed to have contributed to that strain’s high rate of infection.

But Soto-Rifo cautioned that the real effect of the mutations remains unclear.

“However we cannot tell yet what the real impact of these mutations are, since it’s a strain that has shown primarily in South America, and that puts us at a disadvantage, as we don’t have all the resources to execute the needed research,” he said.

Are vaccines effective against Lambda?

With a team of scientists, Soto-Rifo carried out preliminary studies – not yet peer-reviewed – assessing the effect of the Chinese-developed CoronaVac vaccine on the Lambda strain. The results showed that Lambda was able to neutralise the antibodies generated by the vaccine.

Soto-Rifo said part of the vaccine efficacy can be measured by the immunisation response, but also by the responses of T-cells, which stimulate antibody production and help combat the virus-infected cells.

“These results were expected,” Soto-Rifo said. “The virus has changed and that can make the vaccine not as efficient as it was with the original virus, but that doesn’t mean the vaccine doesn’t work any more.

“As a matter of fact, we also know that CoronaVac still has a good percentage of protection against the virus.”

Should we be concerned?

Not yet, said Dr Roselyn Lemus-Martin, who holds a PhD in molecular and cell biology from the University of Oxford and is based in the US.

“At the beginning, we were really concerned… We thought that due to its characteristics, Lambda could become more transmissible than Delta,” Lemus-Martin told Al Jazeera. “But right now, in the US, for example, we’ve seen that Delta keeps being the dominant strain, and what we’ve noticed is that Lambda is not spreading as quickly [in other areas].”

But Tsukayama at Cayetano Heredia University in Lima remains cautious. He said Peru’s research capacity to measure the effect of Lambda is limited, which makes it harder to evaluate the variant’s spread.

“Gamma showed up in Brazil and expanded throughout the region, and it’s already considered a variant of concern,” he said.

“Lambda shares many of the characteristics of Gamma, and it has also spread in other countries. What we don’t have yet is the same amount of evidence Brazilians did. In the region, Brazil leads in their research capacity.”

Source: Al Jazeera

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