Viruses are evolving. SARS-CoV-2, the virus that causes Covid-19, is no exception. So the emergence of variants is no surprise, and not every new genetic mutation poses a serious threat.
But in recent weeks, a growing drum of news coverage has begun to raise alarm over Lambda, a variant first discovered in Peru late in the year. The variant, originally known as C.37, has spread rapidly through parts of South America. On June 14, the World Health Organization designated it as a “variant of interest”, which essentially means that experts suspect it could be more dangerous than the original strain.
“I think some of the interest is just based on the fact that there is a new variant and it has a new name,” said Nathaniel Landau, a microbiologist at the New York University Grossman School of Medicine studying the new coronavirus variants. .
“But I do not think there is any greater cause for concern than before we knew about this variant,” added Dr. Landau. No evidence so far suggests that Lambda will outperform Delta, the highly transferable variant that now dominates most of the world. “There is no reason to believe that this is now any worse than Delta.”
Pablo Tsukayama, a microbiologist at Cayetano Heredia University in Peru who documented Lambda’s emergence, agreed. Latin America has “limited capacity” to conduct genomic monitoring and follow-up laboratory tests of new varieties, he said. This has led to an information gap that raises concerns about Lambda. “I do not think it will get worse than any of the ones we already have,” he said. “It’s just that we know so little that it lends itself to a lot of speculation.”
As of mid-June, Lambda had been reported in 29 countries, territories or territories, according to a June 15 update from the WHO. The variant had been detected in 81 percent of coronavirus samples sequenced in Peru since April and 31 percent of those in Chile to date, the agency said.
The variant accounts for less than 1 percent of the samples sequenced in the United States, according to GISAID, a warehouse for viral genome data. Isolated cases have been reported in a number of other countries.
The variant contains eight remarkable mutations, including seven in the gene for the spike protein found on the surface of the virus. Some of these mutations are present in other variants and can make the virus more contagious or help avoid the body’s immune response.
But big questions remain unanswered. It is not yet clear whether Lambda is more transmissible than other variants, whether it causes more serious illness, or whether it makes vaccines less effective.
“We do not have much information compared to the other varieties,” said Ricardo Soto-Rifo, a virologist at the University of Chile who has studied Lambda.
Preliminary laboratory studies, which have not yet been published in peer-reviewed journals, give cause for both concern and reassurance. In these studies, research groups led by Dr. Soto-Rifo and Dr. Landau that antibodies induced by the Pfizer, Moderna, and CoronaVac vaccines are less potent against Lambda than against the original strain, but that they are still able to neutralize the virus.
The results suggest that these vaccines should still work against Lambda, the researchers said. Moreover, antibodies are not the body’s only defense against the virus; although less potent against Lambda, other components of the immune system, such as T cells, may also provide protection.
“This decrease in the neutralizing antibodies does not mean that the vaccine has decreased effectiveness,” said Dr. Soto-Rifo. Real studies of how well the vaccines keep up with the variant are still needed, he said.
The researchers also reported that Lambda, like several other variants, binds more closely to cells than the original virus strain does, which may make it more transmissible.
Although there are still many questions, Trevor Bedford, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle, said he does not find Lambda as worrying as Delta and does not expect it to become as dominant globally.
“Lambda has been around for a while and it has hardly invaded the United States at all, for example compared to e.g. Gamma ”- the variant that was first identified in Brazil -“ which has done quite well here. ” He added: “I think all focus should be on Delta.”