In-Depth: What is the lambda variant of the coronavirus?

COVID vaccinations in Peru
Posted at 4:53 PM, Jul 27, 2021
and last updated 2021-07-27 20:56:38-04

SAN DIEGO (KGTV) -- The delta variant is now fueling more than 90 percent of the infections in the United States, but recently another variant has started getting some attention: lambda.

The lambda variant was first detected in Peru late last year. (There is conflicting information from the World Health Organization about whether scientists recorded the first samples in August or December of 2020).

Since then, it has become the dominant variant in Peru and spread to other South American countries. Lambda has now been detected in at least 30 countries, according to

As the prevalence of lambda increased in Peru, so did its death rate. Peru now has the highest COVID mortality rate in the world.

The World Health Organization labeled lambda a “Variant of Interest” in June, one step below a “Variant of Concern.”

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UC San Diego virologist Dr. Davey Smith said lambda is the offspring of the gamma variant, the version of the virus that is also called P.1 and was first detected in Brazil.

“Now it evolved and it’s got some key mutations in it that probably make it more infectious. Now it’s out-competed its dad,” he said.

Lambda has several notable mutations found in other concerning variants, including a mutation at the 452nd position in its genetic sequence.

This mutation, called L452Q, changes how the virus attaches to cells and appears to make it sticker and more infectious. This mutation is also in the section of the virus targeted by neutralizing antibodies, Dr. Smith said.

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Several variants have a mutation at position 452, including the delta variant. But lambda’s change is unique; it swapped in an amino acid called glutamine that hasn’t appeared here before.

One study released this month showed this one mutation makes lambda about twice as infectious as the original version of the virus. Another suggests lambda is likely more infectious than both alpha and gamma.

But how does it compare to delta?

“I’m much more worried about delta than lambda,” said UC San Francisco infectious disease expert Dr. Peter Chin-Hong.

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Lamda is still largely confined to South America and accounts for less than 1 percent of sequences worldwide, according to

Delta has been detected in far more countries, at least 112, and accounts for more than 90 percent of recent samples.

“In my gut sense, if delta and lambda went into a boxing ring, delta would probably win,” Dr. Chin-Hong said.

South America’s struggles with lambda may have to do with healthcare inequities, low vaccination rates, and the use of less effective vaccines from China, experts said.

A new study showed the antibodies produced by the Pfizer and Moderna vaccines still neutralize lambda well.

The Johnson & Johnson vaccine showed drops in antibody protection levels against both lambda and delta, but experts said the vaccine will still protect against severe disease.

The study did not evaluate other critical components of the immune system, such as T cells.