A new, little-understood variant of the coronavirus has arrived in North Texas. Doctors at UT Southwestern Medical Center have detected five cases of the so-called lambda variant in patient samples taken at the center between early June and July 18.
“This represents what happens when there is continued viral replication and spread across the entire world,” said Dr. Jeffrey SoRelle, a pathologist at UT Southwestern’s genomic sequencing lab, which has analyzed more than 1,000 samples since the start of 2021.
Little is known about how contagious the lambda variant is or the severity of illness it can cause. Two recent studies, neither of which has been peer-reviewed, found it to be more contagious than older versions of the coronavirus and more resistant to antibodies generated by vaccination.
But SoRelle and other experts say vaccines available in the U.S. remain effective against it.
Lambda was first identified in Peru last December, according to the World Health Organization. It now makes up a majority of cases there.
Since last year, lambda has spread quickly through parts of South America, including Chile and Ecuador. The World Health Organization designated it a “variant of interest” in June, meaning that it has caused “significant community transmission or multiple COVID-19 clusters in multiple countries.”
The Centers for Disease Control and Prevention has not yet followed suit with its own designation. In the U.S., lambda accounted for just .1% of new cases in the last four weeks, according to a database for scientists tracking coronavirus variants.
SoRelle said he is less concerned about lambda than about the delta variant, which now accounts for 95% of new COVID cases in the Dallas area. By some estimates, delta is more than twice as contagious as older versions of the coronavirus. The lambda variant, however, remains at a very low rate of transmission, said SoRelle.
And studies show that vaccines remain effective against it as well as the delta variant. The two recent studies, one conducted by researchers at New York University’s Grossman School of Medicine and another by researchers in Japan, showed that lambda is about two or three times as resistant to antibodies generated by vaccination as older strains of the virus, said SoRelle.
However, that difference is not enough to erode the protection of vaccines.
“It’s statistically significant, but not clinically significant,” he said. Other concerning variants, including beta, first identified in South Africa, and gamma, first identified in Brazil, are seven- to 30-times more resistant to vaccines.
“We find that antibodies raised by vaccination nicely neutralize the lambda variant,” said Nathaniel Landau, a microbiologist at New York University in an email. His team tested antibodies generated by the Moderna and Pfizer vaccines against the virus.
“This means that the vaccines will provide excellent protection against this new variant,” he said. “These findings yet again provide more reason to get vaccinated.”
In fact, there are some signs that lambda may be plateauing on the world stage rather than increasing in prevalence — outcompeted, perhaps, by delta. One coronavirus database appears to show it growing less common in Peru, though recent information is incomplete, scientists said.
The same is true locally.
“A handful of lambda cases have been detected in Texas for quite some time now — with no evidence they have been growing significantly,” said Emma Hodcroft, an epidemiologist at the University of Bern in Switzerland, who tracks coronavirus variants across the globe.
“It would be interesting to know if there is information about the travel history of those who’ve tested positive for lambda,” she said. “My guess would be that a number of these might be imported from South America, and that there might be limited local spread.”
The take-home message from UT Southwestern’s findings, said SoRelle, is that the coronavirus will continue to change and evolve as long as it is being transmitted person-to-person. “If we want to stop hearing about all these different variants,” he said, “vaccination is the best way to keep from creating them.”
