Lambda Is the Latest COVID ‘Variant of Interest,’ Says WHO—Here’s What We Know So Far

Lambda has been reported in 29 countries, and it’s causing concern.

While Americans are facing down the menacing Delta variant, yet another COVID-19 mutation is raising concern around the globe. This one, dubbed the Lambda variant, or C.37, has been identified in multiple countries, mainly in South America.

Here’s what we know so far.

What is the new Lambda variant?

The Lambda variant was first identified in Peru as early as December 2020, according to the World Health Organization (WHO), and it has since been reported in 29 countries.

In Peru, 81% of COVID-19 cases sequenced since April 2021 have been associated with Lambda, per WHO. In Chile, the variant accounts for about a third of sequenced cases reported in the last 60 days.



WHO deemed Lambda a “variant of interest” on June 14. That designation means the resulting mutations are believed to affect the virus’s transmissibility and severity and are causing “significant community transmission or multiple COVID-19 clusters” in multiple countries, such that it appears to be “an emerging risk to global public health.”

Despite the rise Lambda in Peru, scientists are unable to say that the variant is more transmissible, according to the Sun, a UK newspaper. “At the moment there’s no evidence to suggest it’s more aggressive than other variants,” Pan-American Health Organization (PAHO) adviser Jairo Méndez Rico reportedly said. “It’s possible that it has a higher rate of contagion but more work needs to be done on it.”

Public Health England (PHE) subsequently deemed Lambda a “variant under investigation,” per the Independent. However, according to that report, PHE noted that “there is currently no evidence that this variant causes more severe disease or renders the vaccines currently deployed any less effective.”

Are current vaccines effective against Lambda?

There’s not a lot of data yet. Early results of a study out of Peru are based on blood samples from vaccinated health care workers in Santiago, Chile. The findings, which have yet to undergo peer review, suggest that mutations in the spike protein of the Lambda variant are more infectious and better able to escape the neutralizing antibodies elicited by the CoronaVac vaccine (an inactivated SARS-CoV-2 vaccine developed in China not available in the US).

Should Americans be worried about the Lambda variant?

The US Centers for Disease Control and Prevention has yet to identify Lambda as a variant of interest. However, CDC points out that viruses constantly change through mutation and that it routinely monitors SARS-CoV-2 variants in the US.

Several COVID-19 variants that are currently circulating in the US have risen to a more concerning status. Alpha (B.1.1.7 ) Beta (B.1.351), Delta (B.1.617.2 ), and Gamma (P.1) are all classified as “variants of concern,” meaning there’s evidence of increased transmissibility and more severe disease, per CDC.

With the Delta variant now accounting for more than one in four new cases of COVID-19 in the US, President Biden on Tuesday again urged Americans to get vaccinated to slow the spread of virus. “Millions of Americans are still unvaccinated and unprotected. And because of that, their communities are at risk, their friends are at risk, the people they care about are at risk,” Biden told reporters, according to a news report from Reuters. “This is an even bigger concern because of the Delta variant.”


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