is it more contagious, and can it escape vaccines? Virologist explains
The Lambda variant of the coronavirus was first reported in Peru in December 2020, according to the World Health Organization (WHO).
A case of Lambda was checked in in hotel quarantine in New South Wales in April.
Lambda has now been detected in more than 20 countries around the world.
In June of this year, WHO designated it is a “variant of interest”. This is due to mutations believed to affect characteristics of the virus, such as ease of transmission. Although this is not yet of sufficient concern for the WHO to consider it a “variant of concern”, like Alpha or Delta.
Epidemiological evidence continues to accumulate as to the exact threat Lamda poses. So, at this point, more research is needed to determine with certainty how its mutations impact transmission, its ability to evade vaccine protection, and the severity of the disease.
Preliminary evidence suggests that Lambda infects our cells more easily and is somewhat better at dodging our immune system. But vaccines should still do a good job against it.
Lambda more contagious? And can he escape the vaccines?
Mutations affecting the SARS-CoV-2 virus spike protein may increase infectivity, which is the ability of the virus to infect cells.
Additionally, since many coronavirus vaccines currently available or in development are based on the spike protein, changes to the spike protein in new variants may have an impact on the effectiveness of the vaccine
Lambda contains multiple mutations to peak protein.
A mutation (F490S) has already been associated with reduced sensitivity to antibodies generated in patients who had recovered from COVID. This means that the antibodies generated by infection with the original Wuhan strain of COVID are not as effective in neutralizing Lambda.
Another Lambda mutation (L452Q) is at the same position in the spike protein as a studied mutation previously found in the Delta variant (L452R). This mutation in Delta not only increases the ability of the virus to infect cells, but also promotes immune evasion, which means that antibodies generated by vaccines are less likely to recognize it.
Both F490S and L452Q mutations are found in the “receptor binding domain”, which is the part of the spike protein that attaches to our cells.
Read more: Why is Delta such a concern? It’s more infectious, probably causes more serious illness, and defies our vaccines
Preliminary data on the Lambda spike protein suggests that it has increased infectivity, meaning it is more easily able to infect cells than the original Wuhan virus and the Alpha and Gamma variants. These early studies also suggest that the antibodies generated in people receiving the CoronaVac vaccine (developed by Chinese biotechnology company Sinovac) were less powerful to neutralize the spike protein of Lambda than they were the variants of Wuhan, Alpha or Gamma.
It should be noted that infectivity is not the same as being more contagious between people. There isn’t enough evidence yet that Lambda is definitely more contagious, but the mutations it has suggest it is possible.
A separate small study, which has yet to be examined by the scientific community, suggests that the L452Q mutation in the spike protein Lambda is responsible for its increased ability to infect cells. Like the L452R mutation in the Delta variant, this study suggests that the L452Q mutation means that Lambda can bind more easily to the “ACE2 receptor,” which is the gateway for SARS-CoV-2 to enter our cells.
This preliminary study suggests that mutations in the Lambda spike protein reduce the ability of antibodies generated by the Pfizer and Moderna vaccines to neutralize the virus. Also, a mutation was shown to resist neutralization by antibodies of antibody therapy to a certain extent.
Read more: What are monoclonal antibodies – and why we need them and a vaccine
However, these reductions were moderate. In addition, neutralizing antibodies are only part of a protective immune response triggered by vaccination. Therefore, these studies conclude currently approved vaccines and antibody therapies may still protect against diseases caused by Lambda.
Is it more serious?
A risk assessment published by Public Health England in July, admits that there is not yet enough information on Lambda to know whether the infection increases the risk of serious illness.
The risk assessment also recommends that continuous monitoring in countries where Lambda and Delta are present be implemented as a priority. The goal would be to find out if Lambda is able to get ahead of Delta.
With high levels of coronavirus transmission, there is a lawsuit risk of emergence of new variants. The Lambda variant again highlights the risk that these mutations increase the ability of SARS-CoV-2 to infect cells or disrupt existing vaccines and antibodies.
WHO will continue to study Lambda to determine whether it has the potential to become an emerging global public health risk and variant of concern.