Infectivity and immune escape of the new SARS-CoV-2 variant of interest Lambda


Background The newly described SARS-CoV-2 lineage C.37 was recently classified as a variant of interest by the WHO (Lambda variant) based on its high circulation rates in South American countries and the presence of critical mutations in the spike protein. The impact of such mutations in infectivity and immune escape from neutralizing antibodies are entirely unknown.

Methods We performed a pseudotyped virus neutralization assay and determined the impact of the Lambda variant on infectivity and immune escape using plasma samples from healthcare workers (HCW) from two centers in Santiago, Chile who received the two-doses scheme of the inactivated virus vaccine CoronaVac.

Results We observed an increased infectivity mediated by the Lambda spike protein that was even higher than that of the D614G (lineage B) or the Alpha and Gamma variants. Compared to the Wild type (lineage A), neutralization was decreased by 3.05-fold for the Lambda variant while it was 2.33-fold for the Gamma variant and 2.03-fold for the Alpha variant.

Conclusions Our results indicate that mutations present in the spike protein of the Lambda variant of interest confer increased infectivity and immune escape from neutralizing antibodies elicited by CoronaVac. These data reinforce the idea that massive vaccination campaigns in countries with high SARS-CoV-2 circulation must be accompanied by strict genomic surveillance allowing the identification of new isolates carrying spike mutations and immunology studies aimed to determine the impact of these mutations in immune escape and vaccines breakthrough.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

ANID Chile supports the authors through Fondecyt grants numbers 1190156 (R.S-R.), 1211547 (F.V.-E.) and 1181656 (A.G.)

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.


The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol was approved by the Ethics Committee of the Faculty of Medicine at Universidad de Chile (Projects No 0361-2021 and No 096-2020) and Clinica Santa Maria (Project No132604-21). All participants signed the informed consent, and their samples were anonymized.

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.


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