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The lambda variant was first identified in Peru, where it now makes up more than 80 percent of new COVID-19 cases. DIEGO RAMOS/AFP via Getty Images
  • The World Health Organization is monitoring an emerging coronavirus variant that may spread faster and could evade vaccine protection.
  • In June, the WHO labeled the lambda variant of the new coronavirus a “variant of interest.”
  • The lambda variant was first identified in Peru in December 2020.

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As the coronavirus delta variant continues to gain ground in the United States, scientists and public health officials are cautiously monitoring another variant that’s appeared in many countries around the world.

This emerging variant is known as lambda. Here’s what you need to know about it.

The lambda variant was first identified in Peru in December 2020.

In June, the World Health Organization (WHO) labeled lambda a “variant of interest” based on the presence of several concerning genetic changes.

“Lambda carries a number of mutations with suspected phenotypic implications, such as a potential increased transmissibility or possible increased resistance to neutralizing antibodies,” the WHO wrote in its Weekly Epidemiological Update published on June 15.

These mutations suggest the variant might spread faster or evade protection offered by COVID-19 vaccines.

Variants of interest may also cause significant transmission in the community or multiple clusters of COVID-19 cases.

“Lambda has been associated with substantive rates of community transmission in multiple countries, with rising prevalence over time concurrent with increased COVID-19 incidence,” the WHO wrote in its June 15 update.

This has occurred in South America, which is a coronavirus hot spot, with explosive growth in cases and very few people vaccinated due to a shortage of vaccine doses.

Countries there have also seen a rapid spread of lambda.

In December, the lambda variant accounted for 1 in 200 coronavirus samples tested in Peru, according to Financial Times. By March, it accounted for 50 percent of samples in Lima, the country’s capital. Now it is at 82 percent.

Lambda is now in 31 countries, according to data from GISAID, including the United States, United Kingdom, and Canada.

Iswariya Venkataraman, PhD, associate director of scientific affairs at EUROIMMUN, a PerkinElmer company, said viruses frequently evolve via mutations, resulting in new variants of a virus over time.

These mutations can occur anytime the virus replicates.

Many of these changes have no effect, but some mutations can make the virus more transmissible, enable it to cause more severe disease, or allow it to better evade the protection offered by vaccination. Or a combination of these.

In countries with low vaccination rates, and even in areas of the United States where many people are unvaccinated, the virus is able to spread unchecked. This provides additional chances for more harmful variants to emerge.

”For SARS-CoV-2, multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic,” Venkataraman said.

“To date, the main concern of these variants is that they spread more easily from person to person,” she added.

Even if a variant doesn’t cause more severe illness, it can still lead to a rapid rise in COVID-19 deaths if it spreads more easily, especially in areas with low vaccination rates.

Variants of interest differ from “variants of concern” — like alpha, beta, delta, and gamma — which have strong evidence showing they’re more dangerous to people.

Although lambda isn’t a variant of concern right now, this could change over time.

“Considering that this [variant of interest] has rapidly spread in Peru, Ecuador, Chile and Argentina, we believe that lambda has a considerable potential to become a [variant of concern],” wrote Brazilian researchers in a preprint study at the end of June.

Currently, we don’t know for sure whether lambda can evade the immune protection offered by COVID-19 vaccines, but scientists are trying to figure that out.

In one preprint study from early July, researchers from Chile tested the infectivity, or ability to produce infection, of the virus on blood samples taken from people who had received the CoronaVac vaccine, which was developed in China.

Results suggest that lambda is more infectious than alpha and gamma, and that the variant may be able to better evade the antibodies produced after vaccination with this vaccine.

“Our data show for the first time that mutations present in the spike protein of the lambda variant confer escape to neutralizing antibodies and increased infectivity,” the researchers wrote.

The paper has not yet been peer reviewed, so more work is needed to know how concerning the lambda variant is.

As with any coronavirus variant, though, you should be cautious of it. But right now, the delta variant is much more of a concern in the United States.

With delta and other variants of concern, people who are fully vaccinated have a much lower risk of severe illness and death, even if they contract an infection.

But unvaccinated people are at risk from all coronavirus variants.

More than 99 percent of recent COVID-19 deaths in the United States involve unvaccinated people, Dr. Anthony Fauci told NBC’s “Meet the Press” on July 4.

Vaccination offers high protection against the coronavirus. But it’s not the only line of defense.

Wearing face masks in crowded places and practicing physical distancing when possible are also effective ways to protect yourself and others.