Explainer: Everything you need to know about the Lambda COVID-19 variant

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Over the course of the pandemic, several COVID-19 strains have emerged, but a new and potentially more deadly version has now been spotted – the Lambda variant.

Each time the COVID-19 virus mutates it has the potential to become more vaccine-resistant, more transmissible, and harder to stop. Recently, the coronavirus Delta strain, a highly-contagious variant of COVID-19 first identified in India, has caused governments around the world to begin reimposing lockdown and social distancing procedures.

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The new Lambda COVID-19 variant, first identified in Peru in August 2020, has the potential to be even worse, however, with experts suspecting that it might be the most dangerous one yet.

The World Health Organization (WHO) has reported that around 29 countries have logged cases of the Lambda strain, including Chile, Ecuador and Argentina.

Lambda: ‘Variant of Interest’

The WHO categorizes variants based on their severity, and classifies them with letters from the Greek alphabet. The current variants of concern include Alpha (first identified in the UK), Beta (discovered in South Africa), Gamma (first discovered in Brazil) and Delta (identified in India) while variants of interest are Eta (identified in multiple countries), Iota (first identified in the US), Kappa (identified in India), and Lambda.

A scientist analyzes a virus sample. (Unsplash, CDC)
A scientist analyzes a virus sample. (Unsplash, CDC)

The global health agency categorizes strains as variants of concern if it increases transmissibility, is a detrimental change in COVID-19 epidemiology, increases in virulence, changes in clinical disease presentation, or if it decreases effectiveness of public health and social measures, and currently available diagnostic, vaccine and therapeutic methods.

The WHO categorized Lambda as a “variant of interest” in June, cautioning that it might have some mutations that could make it resistant to COVID-19 vaccines, and could be more infectious. But, it has not yet been identified as a “variant of concern”.

“Authorities in Peru reported that 81 percent of COVID-19 cases sequenced since April 2021 were associated with Lambda. Argentina reported increasing prevalence of Lambda since the third week of February 2021, and between 2 April and 19 May 2021, the variant accounted for 37 percent of the COVID-19 cases sequenced,” the WHO noted.

After conducting genomic sequencing in Chile, the WHO found that the Lambda variant made up 31 percent of samples taken. It was also found in 37 percent of the sequenced samples in Argentina, indicating an increase in its prevalence since February 2021.

Some cases of the Lambda variant have made their way to the United States, according to online news media The Hill, accounting for a total of 700 diagnosed cases so far.

It is also important to note that the United States’ Centers for Disease and Prevention (CDC) did not categorize it as a variant of interest, despite the WHO’s ruling on Lambda.

“What’s going on here in the US is Lambda is competing against the Delta variant. And I think it’s losing the competition,” Associated Professor of Biochemistry at West Virginia University Peter Stoilov told online newspaper the Washington Post. “The question is how competitive this variant is going to be. I don’t see it spreading anywhere near as fast as the Delta.”


There is still not enough research on vaccine efficacy against the Lambda variant, but so far available vaccines have worked well against all major strains of the virus, Professor of Medicine at John Hopkins Hospital Dr. Stuart Campbell Ray told online academic news blog Houston Public Media.

Delta is clearly dominating right now. And so, I think our focus can remain on Delta as a hallmark of a highly infectious variant. And there’s some evidence that it might cause greater severity per infection, although that’s still a developing story,” he said.

“We know that vaccination almost uniformly protects people,” Ray added.

He advised that as variants continue evolve, more people will need to get vaccinated against the virus. This, along with mask-wearing and social distancing, will help keep vaccines effective, minimize the risk of severe COVID-19 infections, and reduce deaths and hospitalization, a study by researchers from the Institute of Science and Technology Austria found.

“We found that a fast rate of vaccination decreases the probability of emergency of a resistant strain,” the study stated.

“Counterintuitively, when a relaxation of non-pharmaceutical interventions happened at a time when most individuals of the population have already been vaccinated the probability of emergence of a resistant strain was greatly increased,” the researchers added.

Read more:

Scientists suspect new Lambda COVID-19 variant might be most dangerous

Hard-won gains fighting coronavirus at risk as Delta variant spreads, says WHO

COVID-19 vaccines not strong enough to stop Delta variant alone: Study

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