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Updated 8 July 2021

The Lambda variant of SARS-CoV-2, first identified in Peru and now in over 30 countries worldwide, has been declared as a “variant of interest” by the World Health Organization (WHO) on June 14. 

Scientists and experts see the latest variant of the virus that causes COVID-19 as a fresh threat to the gains made over the last year or so. Read ahead to know all about the Lambda variant of COVID-19. 

C.37 — What is the Lambda variant?

Viruses mutate all the time, producing different versions or variants of themselves. This variant – earlier known as C.37 was first detected in December 2020 in Peru. According to the WHO, Lambda accounted for 82 percent of new COVID-19 cases in May and June in Peru, which has the world’s highest coronavirus mortality rate. 

Lambda has a unique pattern of seven mutations in the spike protein that the virus uses to infect human cells. Researchers are particularly intrigued by one mutation called L452Q, which is similar to the L452R mutation believed to contribute to the high infectiousness of the Delta variant. 

What are the risks associated with the Lambda variant?

The lambda variant is usually associated with higher transmissibility and resistance to antibodies, but health experts have said that more data is needed to establish this fact firmly.

The spike protein of the Lambda variant has a unique pattern of 7 mutations (Δ246-252, G75V, T76I, L452Q, F490S, D614G, T859N) from which L452Q is similar to the L452R mutation reported in the Delta and Epsilon variants. The L452R mutation has been shown to confer immune escape to antibodies and increased viral infectivity. Current data suggests that the L452Q mutation present in the Lambda variant might confer similar properties to those described for the infectivity of the Delta variant

Public Health England in the UK noted that “there is currently no evidence that this variant causes more severe disease or renders the vaccines currently deployed any less effective.”

What are the symptoms of Lambda variant?

Understanding of the Lambda variant is still pretty low, but based on WHO official release, COVID-19 patients will typically exhibit one of these primary symptoms:

  • fever.
  • dry cough.
  • tiredness.

Less common symptoms:

  • aches and pains.
  • sore throat.
  • diarrhoea.
  • conjunctivitis.
  • headache.
  • loss of taste or smell.
  • a rash on skin, or discolouration of fingers or toes.

Where has Lambda variant been located around the world?

Even though the infectivity and transmission rate of the Lambda variant hasn’t been established yet, it has been found in about 30 countries worldwide. While it is clearly the dominant strain in Peru accounting for over 80% of the cases, in Chile, it accounts for more than 31% of the samples from May and June. 

Recently, Public Health England in the UK reported a handful of cases caused by Lambda had been detected in the country and recognized it as having “a potential increased transmissibility or possible increased resistance to neutralizing antibodies.” Having found its way to Europe, where there is already an ongoing battle against the Delta variant, it is still unclear how major a cause of concern the Lambda variant might be due to lack of study.

Pan American Health Organization (PAHO) Regional Advisor on emerging viral diseases, Jairo Mendez, said on 30 June it had been detected in eight countries of Latin America and the Caribbean, “but sporadically in most countries.” Mendez further stated that there was not yet clear evidence it was a more transmissible virus.

Are vaccines effective against the Lambda variant?

At this moment, scientists have no clear answer on this.

Researchers at the University of Chile, Santiago, studied the effect of Lambda on viral infectivity using blood samples from local healthcare workers who had received two doses of the CoronaVac vaccine from China. Their results, published in a preprint paper, suggest that Lambda is more infectious than Gamma and Alpha and better able to escape the antibodies produced by vaccination. 

On the other hand, an NYU Grossman School of Medicine study that hasn’t yet been peer-reviewed, published on July 3, suggested that mRNA vaccines are in fact effective against the Lambda variant. Both Pfizer’s and Moderna’s vaccines are based on mRNA technology.

However, both these studies are yet to be peer-reviewed, and exact data on vaccine efficacy against the Lambda variant are yet to be established. We will update this article as new developments unfold.