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The Lambda Variant: Vaccine Resistant and extra contagious?

  1. The lambda variant has attracted attention as a potential new threat in the development of the COVID-19 pandemic
  2. The lambda variant of the coronavirus, first identified in Peru in December, may decline, but it also has a chance of causing more serious illness if not stopped. Cases were found in Texas and South Carolina, and 81% of the cases in Peru.
  3. The lambda variant has mutations that resist the vaccine.

Two mutations in the Lambda variant – T76I and L452Q – make it more contagious than the COVID variant that swept the world in 2020

The study’s conclusions were in line with results from a team in Chile that found the variant could also escape vaccine antibodies, Chile Infection Control reported.

This report has not yet been reviewed by colleagues.

A variant of COVID-19 proven to be resistant to vaccines is keeping medical experts, public health officials and health professionals at the forefront of the COVID-19 pandemic.

What is the lambda variant according to a study from Chile?

background The newly described SARS-CoV-2 line C.37 was recently classified by the WHO as an interesting variant (lambda variant) due to its high circulation rates in South American countries and the presence of critical mutations in the spike protein. The influence of such mutations on the infectivity and immune defense of neutralizing antibodies is completely unknown.

Methods We performed a pseudotyped virus neutralization assay and determined the influence of the lambda variant on infectivity and immune defense using plasma samples from health workers (HCW) from two centers in Santiago, Chile, who received the two-dose regimen of the inactivated virus vaccine CoronaVac.

We observed an increased infectivity mediated by the lambda spike protein, which was even higher than that of the D614G (line B) or the alpha and gamma variants. Compared to the wild type (line A), the neutralization was reduced by 3.05 times for the lambda variant, by 2.33 times for the gamma variant and by 2.03 times for the alpha variant .

Conclusions Our results indicate that mutations that are present in the spike protein of the lambda variant of interest confer increased infectivity and immune defense against neutralizing antibodies caused by CoronaVac. These data reinforce the idea that massive vaccination campaigns in countries with high SARS-CoV-2 circulation must be accompanied by rigorous genomic surveillance that allows the identification of new isolates with spike mutations and immunology studies aimed at reducing the effects of these mutations to determine immune defenses and breakthroughs in vaccines.

The appearance of worrying SARS-CoV-2 variants and interesting variants was a hallmark of the COVID-19 pandemic in 2021.

The newly assigned SARS-CoV-2 line C.37 was recently classified by the WHO on June 14 as an interesting variant and referred to as the lambda variant. The presence of this new variant was reported in more than 20 countries by June 2021, with most of the available sequences coming from South American countries, particularly Chile, Peru, Ecuador and Argentina5. This new variant of interest is characterized by the presence of a convergent deletion in the ORF1a gene (Δ3675-3677), which has already been described in the beta and gamma variants of concern, and mutations Δ246-252, G75V, T76I, L452Q, F490S, T859N in the spike protein6. The effects of these spike mutations on infectivity and the escape of neutralizing antibodies are completely unknown.

Chile is currently going through a massive vaccination program. According to public data from the Chilean Ministry of Health dated June 27, 2021, 65.6% of the target population (aged 18 and over) received a full vaccination program7. The vast majority (78.2%) of the fully vaccinated population received the two-dose regimen of the inactivated virus vaccine CoronaVac, previously reported to elicit neutralizing antibodies, but with lower titers compared to plasma or sera from convalescent individuals having.

Here we have used our previously described pseudotyped virus neutralization assay12 to determine the influence of the lambda variant on the neutralizing antibody responses triggered by the inactivated virus vaccine CoronaVac. Our data show that mutations in the spike protein give the lambda variant increased infectivity and escape neutralizing antibodies that are triggered by the inactivated CoronaVac virus vaccine.


Health care workers from two locations in Santiago, Chile were invited to participate. Volunteers received the CoronaVac two-dose regimen, with each dose being given 28 days apart according to the Chilean vaccination program. Plasma samples were taken between May and June 2021. All participants signed a declaration of consent before a study process was conducted.

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