As the United States’ recent issues with the Delta variety reveal, it’s never too early to be concerned about a new avatar of the unique coronavirus, given their capacity to spread more easily and evade immunizations. While the United States is dealing with a rapid influx of new infections, scientists are concerned about the introduction of other strains that could further complicate issues. The Lambda variety, called after the 11th letter of the Greek alphabet, is one option that has been identified so far as being primarily limited to South America. They are aware, however, that it does not take much for a new variation to appear in a new territory.
What Is The Lambda Variant?
Also known as C.37, it was first detected in Peru in December last year. It has since been designated as a Variant of Interest (VoI) by the World Health Organisation (WHO), which label is applied to variants “with genetic changes that are predicted or known to affect virus characteristics such as transmissibility, disease severity, immune escape, diagnostic or therapeutic escape”. Which means these can pack all the worrisome characteristics to deal a hard blow to countries trying to return to normalcy.
Basically, to become a Variant of Concern (VoC), of which there are at present four, a variant has to meet the definition of a VoI but with the proven ability at a global level to cause an “increase in transmissibility or detrimental change in Covid-19″ illness, or an “increase in virulence or change in clinical disease presentation”. It could also just be found to contribute to a “decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics”.
A study in Chile, which is in the preprint stage, has sparked concerns about Lambda’s ability to spread infectins and also evade vaccine antibodies.
“Our results indicate that mutations present in the spike protein of the Lambda… confer increased infectivity and immune escape from neutralising antibodies elicited by CoronaVac,” says the study led by researchers at the University of Chile in Santiago. CoronaVac is the Chinese vaccine that is being used in Peru, the country seen as being the worst-hit by Lambda.
Why Are Experts Wary About Lambda?
While a pathogen like the novel coronavirus can take on mutations at a dizzying rate, not all of them will be harmful for humans. That is, most mutations may end up conferring no evolutionary advantage to the virus. However, there are cases when the virus undergoes a genetic update that enables it to spread faster, and also fight off medical counter measures like vaccines and therapies.
The Chile study said that “the spike protein of the Lambda variant confers immune escape to neutralising antibodies elicited by the CoronaVac vaccine. Whether the lambda variant also escapes to the cellular response shown to be elicited by CoronaVac is still unknown”.
Experts have reportedly counted seven mutations in the Lambda’s spike protein, which the novel coronavirus uses to attack human cells, which “may make it easier for Lambda to bind to our cells and make it harder for our antibodies to latch onto the virus and neutralise it”.
The Chilean researchers said the “spike protein of the Lambda variant presented increased infectivity when compared with the spike protein of the Alpha and Gamma variants, both of them with reported increased infectivity and transmissibility”. Alpha, the first VoC flagged by WHO, was first detected in England last September and had sparked a surge in cases there. Gamma is the prevalent strain in Brazil and also a WHO-designated VoC.
What Can Be Done To Counter Lambda?
The drill, experts say, is the same with all variants and should be well-known by now. Confronted with the Delta variant, authorities in the US recommended a return to mask wearing, distancing and frequent handwashing — even for those who have been vaccinated — as a strategy to avoid infection.
Further, experts are calling on governments to expedite their vaccine campaigns and urging that people should not refuse to get vaccinated. That is because even though it is suspected that vaccines may beat antibodies, it is not the only protection offered by a shot and most vaccines have been found to at least reduce the severity of the disease.
“It’s important to remember that neutralising antibodies aren’t the only tool in the immune system’s toolkit — they are merely the easiest to study. T cells play a vital role too, so a handful of mutations… might not be enough to allow Lambda to dodge our immune system altogether,” said Gavi, which is working to ensure equitable distribution of vaccines worldwide. Antibodies are found in the blood, but vaccines also protect at the cellular level, too, including by producing memory B and T cells.
Also, the ability of a variant to escape vaccine antibodies is not total, that is, it differs depending on the vaccine. Preliminary studies suggest that while Lambda could be able to blunt antibodies produced by the mRNA Pfizer and Moderna vaccines as well as the Chinese CoronaVac, they still manage to ‘neutralise’ the virus.
Where Has Lambda Spread?
Concern around Lambda has been fuelled mainly by the rise in cases in the South American countries where it is seen as being the dominant variant. Genetic analysis of the novel coronavirus showed that by April 2021 “it accounted for 97 per cent of all sequences in Peru”.
A weekly WHO Covid-19 update on August 10 said that the Americas had “reported an increase of 14 per cent in new cases as compared to the previous week, with just under 1.4 million new cases” while there was a “slight decrease in the number of weekly deaths as compared to the previous week, with nearly 20 000 new deaths reported”. It said that “the increase in weekly cases is mainly driven by Peru”, which recorded a 64 per cent jump, and the US, where cases were up by 35 per cent over the previous week.
Adding to fears is the death rate in Peru, which is the highest in the world at more than 600 for every 100,000 individuals. The country of a little over 33 million people has had more than 2 million confirmed cases with the COvid-19 death toll just shy of 200,000. Gavi said the high death toll can be partly explained by Peru’s “poorly funded, under-prepared healthcare system with too few ICU beds; slow vaccine rollout; limited testing capacity; a large informal economy (few people could afford not to work); and overcrowded housing”.
But Lambda is gradually being reported in more and more countries. A mid-June update by WHO had said that samples of the Lambda variant had been detected in at least 29 countries. As of August 12, outbreak.info said that “the strain has been detected in at least 44 countries and 45 US states” although it so far constitutes only 0.5 per cent of all strains reported worldwide.
Indian health authorities had said in early July that the variant had not been detected in the country.
“As far as we know it has not entered our country, we have not detected this variant in our country. Our surveillance system INSACOG is very effective and it will detect it if it happens to enter our country because when you do sequencing, all this will be picked up,” NITI Aayog member Dr VK Paul had said. Genome sequencing trackers like Gisaid and outbreak.info reported that six samples out of more than 43,000 from India showed a Lambda infection but none in the last four weeks.
