The SARS-CoV-2 Lambda variant, also known as lineage C.37, is a variant of SARS-CoV-2, the virus that causes COVID-19. It was first detected in Peru in December 2020. On 14 June 2021, the World Health Organization named it Lambda variant and designated it as a variant of interest.

The lambda variant of the novel coronavirus has received a flurry of news coverage since it was added to the World Health Organization variant watch list in June. Lambda swept through several South American countries earlier this year and has been detected in parts of the United States, including this week at a major hospital in Houston.

Infectious-disease experts aren’t sounding any alarms about lambda yet. Its progress here has been slow, with fewer than 700 cases identified since it emerged in the country months ago. Moreover, experts say the threat from lambda is insignificant next to the highly transmissible delta variant, which is spreading rapidly among unvaccinated people and causing hospitalizations to spike for the first time in months.

What you need to know about the highly contagious delta variant

“It is not anywhere near as concerning as the delta variant,” said S. Wesley Long, medical director of diagnostic microbiology at Houston Methodist Hospital, which on Monday reported its first case of the lambda variant. “That’s the engine that’s going to be driving the surge in the U.S.”

Still, scientists are studying the lambda variant, which has shown signs of being more transmissible than milder versions of the coronavirus. Here’s what you need to know about it.

According to experts, lambda has some of the same types of mutations observed in the alpha, beta and gamma variants that may increase transmission. It also has a mutation similar to one found in delta that may allow it to more easily infect lung cells.

But the WHO designation is less severe than “variant of concern,” a label the agency reserves for variants that have been shown more definitively to spread faster, make people sicker, or evade vaccines or treatments. That group includes the alpha, beta, gamma and delta variants.

How effective are vaccines against the lambda variant?
According to Washinton Post, even if the lambda variant were to surge in the United States, there’s good news: Two of the three federally approved coronavirus vaccines appear to work well against it.

A paper posted Monday by Landau and other researchers at NYU found that the Pfizer and Moderna vaccines had no problem neutralizing lambda. The variant showed a slight resistance to the two mRNA vaccines, but the shots were still highly effective, according to the study, which has not yet undergone peer review.

“The vaccines induce such good antibodies that even if the virus is a little bit resistant, they are still quite sufficient to kill the virus,” Landau said.

The Johnson & Johnson vaccine, on the other hand, doesn’t offer the same defenses against lambda or delta, the researchers found.

Still, Landau was quick to point out that the Johnson & Johnson vaccine offered other benefits, including its ability to help the body’s T cells fight infection.

“There’s no reason to think that the T cell response isn’t as good,” he said. “It would still be there to block variant viruses.”

Experts stressed that vaccines were the most important tool for combating the coronavirus, regardless of the variant. Long, of Houston Methodist, said people now have a choice: either get vaccinated or, eventually, get infected.

“No matter what Greek letter comes along next, the vaccine is really our best defense,” Long said. “If anybody thinks they can hunker down and never get the virus, I think that’s a fantasy.”