Lambda COVID variant: All you need to know about the new UK coronavirus strain © Getty Images

Lambda COVID variant: All you need to know about the new UK coronavirus strain

The WHO is keeping a close eye on the spread of the new coronavirus strain, which is dominant in Peru and has now reached the UK. Here's what we know about the Lambda variant.

The WHO and the UK Government are continuing to track the spread of the Lambda variant of coronavirus, which has become the dominant strain in Peru. The new variant, which has also been called C.37, accounts for 71 per cent of all COVID-19 cases in Peru from January to June 2021.


Peru’s Minister of Health, Óscar Raúl Ugarte Ubilluz, said that the Lambda strain has now spread around the world.

“[The Lambda variant] has been identified in the United States, Chile, Brazil, Argentina, Ecuador, Mexico, Spain, Germany, not only in Peru. 623 samples from 19 regions have been studied since April, through what is called genomic sequencing, that is, the genomic analysis in its composition, to determine the currently circulating variants.”

Read more about coronavirus variants:

Some scientists have warned that the Lambda strain could be more transmissible than the Delta variant, which is currently the dominant strain in the UK.

A pre-print analysis, which has yet to be peer-reviewed, of the spike proteins on the SARS-CoV-2 Lambda variant showed a two-fold increase in infectivity, which scientists say is due to a particular mutation on the virus called the L452Q mutation.

The researchers at the NYU Grossman School of Medicine tested the effectiveness of mRNA vaccines – like the Pfizer and the Moderna coronavirus vaccines used in the UK – against the Lambda variant.

According to their results, there was a “partial resistance to neutralisation”, however this “is not likely to cause a significant loss of protection against infection” in vaccinated individuals.

This map shows occurrences of the Lambda C.37 variant. The circle size is proportional to the number of variant genomes, while the colour indicates how recent the cases are, with red the newest confirmed infections © GISAID Initiative
This map shows occurrences of the Lambda C.37 variant. The circle size is proportional to the number of variant genomes, while the colour indicates how recent the cases are, with red the newest confirmed infections © GISAID Initiative

The Lambda variant was first detected in Peru in August 2020, and it was classified as a variant of interest at the global level by the World Health Organization (WHO) on 15 June 2021.

This means the WHO consider it to have mutations with established, or suspected, implications for its transmissibility and severity, and has been detected in multiple countries.

Dr Maria Van Kerkhove, the WHO’s technical lead on COVID-19, said that they are tracking this strain to see if it should be classified as a variant of concern. This would happen if the strain “demonstrated properties of increased transmissibility”, or “if it has increased severity,” she said.

The Lambda variant will only be designated a variant of concern if it is deemed to either: increase the transmissibility of the virus; show a detrimental change in its epidemiology; increase in virulence; change the disease presentation/symptoms; or shows decrease in the effectiveness of testing, treatment, and prevention measures such as vaccinations.

How many cases of the Lambda variant have been detected in the UK?

As of 16 July 2021, there have been eight confirmed cases of the C.37 variant in the UK, all in England. This has not increased from the figure reported on 9 July. The majority of these are linked to overseas travel, according to a PHE spokesperson.

A report by PHE on the variants of concern or under investigation in the UK shows that the Delta variant continues to be the prominent strain in the UK. In the week leading up to 7 July 2021, there were 36,800 new cases of the Delta variant.

“There is currently limited evidence available about this variant,” Dr Alicia Demirjian, COVID Incident Director at Public Health England (PHE), told BBC Science Focus magazine.

“PHE, together with academic partners, is undertaking investigations to better understand the impact of the mutations on the behaviour of the virus. We are closely monitoring the situation in those countries where this variant is prevalent and where cases are detected in the UK, we are testing contacts and will undertake targeted case finding if required.”

Will vaccines still work against the Lambda variant?

In a pre-print paper that has not yet been peer-reviewed, researchers found that mRNA vaccines are effective against the Lambda variant. Both the Pfizer and the Moderna coronavirus vaccines used in the UK are mRNA jabs, meaning they contain genetic material that instructs the body’s cells to produce coronavirus spikes, which then provokes an immune response.

The results of this paper suggest that vaccines in current use will remain protective against the Lambda variant.

However, in another pre-print paper, Lambda was found to have mutations that had “the ability to escape from neutralising antibodies elicited by CoronaVac“. CoronaVac is a vaccine being used in several Asian countries, and works by administering an inactive version of the SARS-CoV-2 virus, which then triggers an immune response.

Researchers have stressed that further studies are required to validate the effectiveness of vaccines.

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Is the Lambda variant more transmissible?

While it is not known yet whether this new variant is more transmissible, scientists say the Lambda strain does carry a number of mutations that could potentially lead to increased transmissibility or increased resistance to the antibodies provided by a COVID-19 vaccination or prior exposure to the virus.

One of the mutations identified in the Lambda strain is referred to by scientists as T859N, and has been found in the so-called ‘Iota’ variant currently spreading in New York City.

Another mutation, at L452Q, is reported as being “similar to the mutation reported in the Delta and Epsilon variants” which is believed to affect its susceptibility to antibodies.

However, it’s important to note that research on this specific variant is all in early stages.

As there is currently little evidence to show exactly how the Lambda variant is different to the other strains, scientists say that further, more robust studies, are needed before we can understand the full extent of the strain’s effect.

What are the symptoms of the Lambda variant?

At present, there is nothing to suggest that the symptoms of infection with the new C.37, or Lambda, variant are different to other coronavirus strains.

The main symptoms of COVID-19, according to the NHS, are:

  • a high temperature – this means you feel hot to touch on your chest or back (you do not need to measure your temperature)
  • a new, continuous cough – this means coughing a lot for more than an hour, or three or more coughing episodes in 24 hours (if you usually have a cough, it may be worse than usual)
  • a loss or change to your sense of smell or taste – this means you’ve noticed you cannot smell or taste anything, or things smell or taste different to normal

The NHS say that most people who have symptoms of COVID-19 will have at least one of the above.

What other variants of concern have been identified in the UK?

It is common for viruses to mutate when they replicate. Few of these small, genetic changes lead to a more harmful infection.

As of 16 July 2021, there are five strains considered to be ‘of concern’ by PHE, including the Delta and Alpha variants.


The UK Government has a deal with biopharmaceutical company CureVac to develop vaccines against future variants, and has pre-ordered 50 million doses.

About our expert, Dr Alicia Demirjian

Dr Demirjian is the COVID Incident Director at Public Health England (PHE). She is a clinician and epidemiologist, and trained at Boston Children’s Hospital in general paediatrics and paediatric infectious diseases. Demirjian works as a consultant at Evelina London Children’s Hospital alongside her work with PHE.