Lambda Variant Concerns: Transmissibility, Vaccine Efficacy


The lineage C.37, (Lambda variant), was recently classified as a variant of interest by the World Health Organization (WHO) based on its high circulation rates in South America, and has showed "the ability to escape from neutralizing antibodies elicited by CoronaVac."


This article was originally posted on Infection Control Today.

A COVID-19 variant that has demonstrated to escape from neutralizing antibodies keeps medical experts, public health officials, and health care professionals—including infection preventionists—on the frontlines of the COVID-19 pandemic up at nights. There’s no reason to sound the alarm yet, but there may—just may—perhaps be reason to think that there’s a chance that the alarm may have to be sounded at some point about the lambda COVID-19 mutation, or C.37.

A preprint study by investigators in Chile suggests that the mutation, which first surfaced in Peru about a year ago and is highly infectious, may also be able to evade vaccine antibodies.

“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,” the study states. CoronaVac is a vaccine manufactured by a Chinese company and that’s used in Peru. The study continues: “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.”

Peru has the highest COVID-19 death rate of any country in the world, according to the Johns Hopkins Coronavirus Resource Center: about 600 for every 100,000 people infected with COVID-19. That’s about twice the amount of Hungary, the country with the next highest COVID-19 death rate. The WHO says that the lambda variant has been the COVID carrier in about 81% of infections in Peru since April. The WHO declared the lambda variant a variant of interest last month. The lambda variant has spread to about 30 other countries in the world, including the United Kingdom.

The first case of lambda variant has been spotted at Houston Methodist Hospital about 3 days ago, according various news outlets, including Axios. An ironic development, as Houston Methodist Hospital has sparked headlines lately by being the first hospital in the US to mandate that all its employees get the COVID-19 vaccine. As Infection Control Today reported, 153 of Houston Methodist Hospital’s employees either resigned or were fired for not getting the vaccine. KHOU 11 reports that there’s been an alarming spike in COVID-19 infections in the Houston area. Houston Methodist Hospital officials have not commented on whether the loss of those 153 employees has hindered the facility’s ability to treat the influx of patients.

The Chilean investigators give an indication of what challenges the lambda variant presents, writing that “our results indicate that the spike protein of the lambda variant confers immune escape to neutralizing antibodies elicited by the CoronaVac vaccine. Whether the lambda variant also escapes to the cellular response shown to be elicited by CoronaVac is still unknown. We also observed that the spike protein of the lambda variant presented increased infectivity when compared with the spike protein of the Alpha and Gamma variants, both of them with reported increased infectivity and transmissibility.”

Kevin Kavanagh, MD, a member of ICT's Editorial Advisory Board, argues that the emergence of the Lambda variant underscores the need to consider vaccines just 1 layer of protection against COVID-19 infection, and that they should be combined with masks.

“It needs to be remembered that a high-quality mask or respirator can decrease viral exposure up to sixfold, making them an important adjunct to vaccines with reduced efficacy,” Kavanagh tells ICT. “Our goal needs to be to prevent both death and long-term disability.”

Slow the spread and the mutations of COVID-19, Kavanagh urges. And though there may be very few cases of the lambda variant in the US, it still “underscores the need for travel restrictions, including quarantining of returning [travelers], regardless of vaccination status,” says Kavanagh. “We also need to pivot away from our current two-tiered advisories regarding vaccinated and unvaccinated individuals. With the lambda and Delta variants we all should become vaccinated plus follow public health advice.”

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