How does the lambda variant compare to the delta variant of COVID-19?

lambda variant covid vs delta variant
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The lambda variant of COVID-19 was discovered in a Houston hospital on July 20, leading to new concerns from scientists and health officials monitoring the pandemic. The rise in COVID cases and deaths is attributable to the delta variant’s spread among unvaccinated Americans. But when comparing the lambda vs. the delta variant, how do the two strains compare?

As Nautilus wrote on July 7, “The lambda COVID variant is extremely transmissible. Experts believe ‘its rate of transmission is higher than any other variant,’ according to Professor Pablo Tsukayama of Peru’s Cayetano Heredia University.”

ABC News consulted with Dr. Wesley Long, medical director of Diagnostic Microbiology at Houston Methodist, in its July 21 coverage of the Houston discovery. He said, “The lambda is the dominant variant in Peru and Peru has had a very difficult time with COVID-19. It shares mutations in common with the alpha variants, the beta, the gamma, which is the dominant variant in Brazil.” 

But when making comparisons for the lambda variant vs. the delta, he said, “I don’t think there’s sufficient evidence at this point that we should be more concerned about lambda than delta. I still think delta is the primary concern for us. There’s a lot more evidence that we have that delta is much more contagious, the viral loads are much higher.” 

Some of the lambda mutations occur in its spike protein, according to USA Today. That’s significant because it’s the part of the virus that helps it penetrate cells in the human body—and it’s also the part of the virus that vaccines are targeting.

But Long said that the lambda mutations are similar to other variants of concern, like alpha and gamma. Even gamma (which, unlike alpha or delta, hasn’t been a big factor in U.S. COVID cases) has more concerning mutations than lambda.

The Conversation, looking at existing evidence on the lambda variant, surmised that it “has an easier time infecting our cells and is a bit better at dodging our immune systems,” though some existing vaccines can combat it effectively. The CoronaVac vaccine (developed by China’s Sinovac), however, showed less effectiveness with the lambda variant than with others. 

Lambda (aka C.37) was first detected in Peru in August 2020 and has spread to 29 nations, including many Latin American countries, according to National Geographic. In addition to being blamed for the Peruvian outbreak in the spring of 2021, the lambda variant has also been linked to an outbreak in Chile, where CoronaVac is the primary vaccine being used. 

“A study by the University of Chile found that a single dose of the CoronaVac vaccine was only 3% effective,” the National Geographic article alarmingly noted, “but that rose to 56.5% after both doses.” 

Read more on the delta variant: 

Sources: ABC News, USA Today, The Conversation, National Geographic

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