Lambda, variant of interest
Source: By Amitabh Sinha: The Indian Express
Even as the Delta variant of the SARS-CoV-2 coronavirus continues to drive the rise in infections around the world, another variant, Lambda, is increasingly being seen by scientists and health experts as a new emerging threat. On 14 June 2021, the World Health Organization designated the Lambda variant, previously known by its formal scientific name C.37, as the seventh and newest “variant of interest”, meaning it was something to watch out for.
Like the Delta variant, the Lambda variant, which has now been detected in more than 25 countries, is feared to be more transmissible than the original virus, although it is not yet established because of lack of enough studies on it. It has been the dominant variant in Peru and other countries of South America. The Lambda variant has not yet been found in the Indian population, but has recently been detected in the UK and other European countries.
The Lambda variant is not a new emergence. It has been around at least since last year, possibly as early as August 2020. In Peru, where it is believed to have originated, it accounts for almost 80% of the infections. It is the dominant strain in neighbouring Chile as well. But until recently, it was largely concentrated in a handful of South American countries, including Ecuador and Argentina.
Since the end of March, this variant has been detected in more than 25 countries, although the numbers are still very small. The UK, for example, said it had found this variant in six infected people, all international travellers. Recently, it has also been found in Australia.
According to the WHO, the Lambda variant has at least seven significant mutations in the spike protein (the Delta variant has three) which could have a range of implications, including the possibility of increased transmissibility or enhanced resistance to antibodies, created either through natural infection or vaccination.
A recent study by researchers at Chile reported that the Lambda variant had greater infectivity than the Alpha and Gamma variants (known to have originated in the UK and Brazil respectively). The study also reported decreased effectiveness of the Chinese Sinovac vaccine (Corona Vac) against the Lambda variant.
However, the behaviour of the Lambda variant is not very well understood right now.
“There is currently limited evidence on the full extent of the impact associated with these genomic changes, and further robust studies into the phenotype impacts are needed to better understand the impact on countermeasures, and to control the spread,” the WHO said in a statement. “Further studies are also required to validate the continued effectiveness of vaccines.”
But, the designation as a “variant of interest” means that the genetic changes involved are predicted or known to affect transmissibility, disease severity, or immune escape. It is also an acknowledgement of the fact that the variant has caused significant community transmission in multiple countries and population groups.
There are currently seven variants, including the Lambda that the WHO classifies as “variants of interest”. Another four – Alpha, Beta, Gamma and Delta – have been designated as “variants of concern”, and are considered a bigger threat. These were all recently named after letters of the Greek alphabet to avoid linkage with the country of their origin that had been happening until then.
The Lambda variant has so far not been found in India or neighbouring countries. In Asia, only Israel has reported this variant until now. But several countries in Europe from where travel to India is frequent, including France, Germany, UK, and Italy have reported this variant.
The potential of emerging variants to bypass the immunity gained through vaccination means that there could be fresh waves of infections even in populations that were being considered close to reaching community-level protection. That is what is happening in many countries in Europe right now, particularly in the UK. There has been a sharp rise in cases in several countries in the last few weeks.
That means that a country like India, which is still recovering from the debilitating second wave, would need to proactively watch out for, and prevent the spread of any new variant that could trigger a fresh wave.
