What Experts Learn About Lambda, a ‘Variant of Interest’ of the Coronavirus

By Jacqueline Howard | CNN

As the coronavirus pandemic continues, infections caused by the Lambda variant have emerged in the United States, including Texas, where the Houston Methodist Hospital reported its first case last month.

Genomic sequencing has so far identified 1,060 cases of Covid-19 caused by the Lambda variant in the United States, according to the independent data sharing initiative GISAID. While that number is nowhere near the increase in the number of cases caused by the Delta variant – accounting for around 83% of new cases in the United States – infectious disease experts have said Lambda is a variant they are watching closely. .

The Lambda variant was first identified in Peru in December. The World Health Organization designates Delta as a “variant of concern”. Lambda is designated a lower degree as a “variant of interest”.

“I think anytime a variant is identified that demonstrates the ability to spread rapidly in a population, you have to be concerned,” said Dr Gregory Poland, professor of medicine and director of the Vaccine Research Group at the Mayo Clinic in Rochester, Minnesota, told CNN Friday.

“There are variants that arise every day – so a variant can be defined as new mutations,” he said. “The question is, do these mutations give the virus some sort of advantage, which of course is disadvantageous for humans?” The answer in Lambda is yes.

What do we know about Lambda

There is still a lot to learn about Lambda.

The variant is not as worrisome as the Delta variant in the United States, which has seen an increase in cases nationwide, but early studies suggest it has mutations that make it more transmissible than the strain of origin of the coronavirus.

“Lambda has mutations of concern, but this variant remains quite rare in the United States despite its presence for several months,” wrote Dr. Preeti Malani, health officer in the division of infectious diseases at the University of Michigan. in Ann Arbor. email on Friday.

“It is difficult to know for sure how transmissible Lambda is and how well vaccines work. So far it appears that Lambda is more transmissible than the original SARS-CoV-2 virus, ”which is similar to Delta and other variants, wrote Malani, an expert with the Infectious Diseases Society of America. . SARS-CoV-2 is the name of the coronavirus that causes Covid-19.

“Fortunately, studies suggest that currently available vaccines remain protective. We learned during the pandemic that things can change quickly, so controlling the spread of COVID-19 in general will help manage Lambda, ”Malani wrote. “As long as there is an uncontrolled spread of SARS-CoV-2, we will see more variants in the future. The only way out is a widespread vaccination to control the spread and prevent another mutation in SARS-CoV-2. It’s a race between vaccinating a sufficient amount of the world and developing new variants less susceptible to countermeasures. “

So far, data remains mixed on how vaccines protect against the Lambda variant, and scientists say they need to study this further.

In July, researchers wrote in a lab study that they had found evidence that people who received the single-dose Johnson & Johnson Covid-19 vaccine could benefit from a booster dose to better protect them from the new variants. of the coronavirus, including the Lambda variant. The study was performed in the lab and does not reflect the actual effects of the vaccine – and it is posted online as a preprint on the biorxiv.org server, which means it was not submitted to careful peer review.

Nathaniel Landau of the Grossman School of Medicine at New York University and colleagues said their blood tests from vaccinated volunteers showed that at least some of the newer variants emerging could escape the protection offered by a single dose of the drug. Johnson & Johnson Janssen vaccine. A boost from a second dose of J&J vaccine, or even with Moderna or Pfizer, could help, the researchers reported.

In the study, the Beta, Delta, Delta plus and Lambda variants showed only “modest” resistance to the antibodies caused by the Pfizer / BioNTech and Moderna coronavirus vaccines, suggesting that the vaccines still work.

A separate preprinted article, published last week on the online server biorxiv.org, revealed in lab experiments that three mutations – called RSYLTPGD246-253N, 260 L452Q, and F490S – found in the spike protein of the Lambda variant may confer resistance to vaccine-induced immunity, but more research is needed. The article, written by Japanese scientists, has yet to be published in a peer-reviewed journal.

“Two additional mutations, T76I and L452Q, help make Lambda highly infectious. Currently, the Lambda variant has been reported as a “variant of interest” by the WHO. We do not yet know if this variant is of more concern than the Delta variant, ”wrote pharmacist and epidemiologist Dr. Ravina Kullar, an expert with the Infectious Diseases Society of America on Friday.

“Further genomic surveillance studies need to be conducted to assess how vaccine efficacy is affected by the Lambda variant,” Kullar wrote. Until Covid-19 cases globally decline, “the best way to prevent the emergence of more variants is to get fully vaccinated, not to travel abroad, and to follow strict safety measures. prevention of infections, including wearing a face mask, physically distancing from others, and not attending large social gatherings. gatherings.

A game of “Russian roulette”

Vaccines are essential for countering newer variants of the coronavirus, such as Lambda, which may remain rare in the United States but is associated with “substantial rates of community transmission in several” countries in the region, according to the WHO.