The WHO declares new SARS-CoV-2 ‘variants of interest’ if a new variant has become prevalent in multiple countries and if there is some other preliminary evidence that a new variant potentially has a ‘competitive edge’.

It is in the nature of viruses that they gradually, and quite randomly, change their genetic makeup as long as they circulate in the community. Most new variants that come into existence don't ‘perform’ as well as the original virus and so they just quietly disappear. But occasionally a variant will acquire some advantage and then it will eventually outcompete the original virus. Causing more serious disease isn’t typically to the virus’ advantage but an increased ability to infect new people is. This advantage could come about in multiple ways. For example, the variant virus’ spike protein could bind more strongly to receptors on target cells or it could better evade recognition by the immune system of vaccinated people, which was ‘pre-trained’ only on the original virus.

The SARS-CoV-2 Lambda (C.37) was recently listed as a variant of interest by the WHO due to its spread from Peru into much of South America and the presence of critical mutations in its spike protein. A Chilean study—not yet peer-reviewed—looked at the features of the lambda variant spike protein in simplified lab experiments, finding that it could contribute to both, greater cellular infectivity as well as some evasion of the immune system of people vaccinated with CoronaVac, the mainstay of the Chilean vaccination effort.

What does this mean for Australia? It is too early to tell and sound the alarm bells. First, the Chilean study was lab-based and, while providing interesting leads, its findings can’t be directly extrapolated into ‘real-life’. So, in terms of infectivity, it remains to be seen if lambda can outcompete the highly infectious delta variant in actual community transmission. Second, CoronaVac is an inactivated virus vaccine, a proven technology that nevertheless appears somewhat less effective than the viral vector (Astra-Zeneca) or mRNA (Pfizer-BioNTech) vaccines used here in Australia. So, pending scientific tests, lambda might be expected to have a tougher time getting past the immune defences of vaccinated Australians. New virus variants will likely continue to emerge but the bottom line is that people should get vaccinated.

Lambda has a mutation which is similar to the one seen in Delta and Epsilon variants but it is still uncertain if this will increase its level of infectiveness. We may all gain a better understanding of the Greek alphabet from COVID-19 variants however the most important concern remains for widespread vaccination to prevent serious illness from the virus.

One of the key missing pieces of the puzzle for COVID-19 vaccines is a correlate of protection. Put simply - what level of antibody do you need to confer protection against the virus?
 
Traditionally this can be obtained from large scale clinical trials with comparisons made of vaccinated people who don’t get infected versus vaccinated people who do get infected. This comparison has proven difficult for the mRNA vaccines (Pfizer and Moderna) which produce large levels of neutralising antibodies.
 
The process also gets a bit tangled up when deciding if levels of neutralising antibody is the best correlate of protection. The AstraZeneca COVID-19 vaccine produces better T cell responses than the mRNA vaccines.
 
Deciding which of these is the better (or best) marker for a correlate of protection becomes difficult. Determination of a correlate of protection for COVID-19 vaccines is further complicated by a moving target.
 
Since the emergence of the SARS-CoV-2 pandemic, several variants of the original Wuhan virus have emerged, so protection is now relative to the version of the virus a person has contracted. The emergence of the Lambda variant of the virus in Australia once again raises concerns of whether this version of the virus is going to be more infectious and which COVID-19 vaccine is going to be more effective.

In my opinion it's too early to tell what the impact of this variant will be.  In Lima this variant has become the predominant COVID virus, and it appears to be spreading throughout South America.  But what does this mean?  In South America the predominant vaccine used is not the AZ or Pfizer, so does this mean that other variants are more effectively controlled allowing the Lambda variant to proliferate?  Is there something special about this variant which allows it better survive in the environmental conditions found in South America?  Given the observation that this variant has been found in multiple countries including the UK and Australia without little spread does this mean it's less infective?
 
What we do know is that in a non-peer reviewed preprint paper using surrogate COVID viruses (these were HIV which express the COVID spike protein) that the serum from people vaccinated with the inactivated virus vaccine CoronaVac has reduced ability to inactivate the Lamdba variant, but there was also reduced inactivation of Alpha and Gamma variants compared to the original COVID virus. 
 
Until there is more data it’s anyone’s guess how aggressive this variant will turn out to be.

It [Lambda] will be one of many 'contemporary variants' that will appear over time. To put it into context, it is like talking to a patient with HIV or another infectious disease about each quasi species of the virus that they have. In that context, we focus on when the virus has changed to something significant. Eg. Drug resistance. In that setting we change their treatment. For SARS CoV2 it’s more about when it reaches a point of vaccine resistance that we require another vaccine formulation and/or booster... that’s when we need to change the treatment.
 
We need to look at the contemporary variants with broader brush strokes now. How do we do this? If one supplants another.

Eg. Does Lambda now outcompete Delta when it arrives in a country? Does Lambda consistently break through people listed with two doses of their vaccine (and across the current vaccine with the better efficacy). Does Lambda present with greater disease severity and deaths than other variants? 

The jump from Variant of Interest (VUI) to a Variant of Concern (VOC) does this. It takes big numbers globally and is considered by many experts.
 
It’s not a VOC as the data is yet to accumulate… the dust needs to settle. 
 
There will be more and we may indeed need another alphabet to work with.

The SARS-CoV-2 Lambda variant was initially reported in Peru in December 2020. On 14th June 2021 the WHO designated Lambda a Variant of Interest, due to its genetic changes that are known to affect susceptibility to antibody neutralization.

Lambda contains genetic changes found in Variants of Concern Alpha, Beta, and Gamma. Lambda has also been associated with significant community transmission in multiple countries, expanding rapidly in South America. Preliminary studies performed on cells in a laboratory suggest the infectivity of Lambda is higher than Variants of Concern Alpha and Gamma.

Additional preliminary studies indicate that antibodies generated in people receiving the CoronaVac vaccine (developed by Sinovac, Beijing, China) were less potent at neutralising the spike protein of Lambda than they were the Alpha and Gamma strains of SARS-CoV-2.

As of 7 July 2021, GISAID — the world’s largest database of SARS-CoV-2 virus genome sequences — had a total of 2.22 million entries of which 2,235 constitute the Lambda variant.  

Of the 2,235 Lambda genome sequences on GISAID, three were isolated from cats in Peru and the remaining 2,232 from humans. The variant has spread to 29 countries including Australia, which recorded the Lambda variant on 3 April 2021, isolated from a 28-year-old male in Sydney.  

Many of the affected locations are in South America, predominantly Peru, although the first sample collection appears to be from Argentina on 8 November 2020.  

The Lambda variant has an eclectic set of mutations, many of which appear to be immune evasions — that is, allowing the virus to evade a person’s immune response. Six of the key mutations in the virus’ spike protein appear as three ‘pairs’ of substitution mutations in close proximity.  

Outside the spike, one of the changes (the 106-108 deletion in ‘nsp6’) is common to the Alpha, Beta and Gamma variants of concern. Interestingly, the L452Q substitution is a moderately radical change, and we encounter something similar (the L452R substitution) in both the Delta variant of concern and the Epsilon variant of interest. 

At this stage, the Lambda variant is definitely of structural interest, but will require further epidemiological evidence and peer-reviewed studies on infectivity and impact on vaccines to determine if it is a variant of concern.