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While the delta variant of the coronavirus has quickly become the dominant strain in the United States, it is not the only variant circulating in the population.
The lambda variant, first identified in Peru, is also making headlines as it began to be identified in several states. Houston Methodist Hospital reported its first variant case this week. Scientists at the South Carolina University of Medicine recently announced that they had found the variant in a sample of the virus taken in April.
According to a database for scientists who track COVID-19 variants, fewer than 700 cases of the lambda variant have been sequenced in the United States so far out of the more than 34 million total cases reported to date. But the United States has only sequenced a tiny fraction of its cases, so that number doesn’t reflect the actual number of average cases in the country.
Less than 1% of U.S. cases in the past four weeks have been identified as the lambda variant, according to GISAID, a genomic data repository.
So should we add lambda to our list of big worries in the USA? Not yet, according to public health officials and experts.
The delta variant, which is more than twice as transmissible as the original strain of the coronavirus, now accounts for 83% of new coronavirus cases in the US Delta continues to be the main concern of public health officials.
What we know about the lambda variant
The lambda variant was first identified in Peru in August 2020, according to the World Health Organization. Cases with the variant have now been identified in 28 countries, according to GISAID – although many of them have only identified a handful of lambda cases.
Dr Stuart Ray is Professor of Medicine at Johns Hopkins Hospital, where he specializes in infectious diseases. Ray opened one of the first COVID-19 departments at Johns Hopkins in March 2020, and he also oversaw Johns Hopkins’ COVID-19 sequencing efforts.
He tells NPR that lambda is “kind of a cousin of the alpha variant” – one of the first worrying variants identified.
Lambda spread until it became a dominant streak in people with COVID-19 in Peru. The WHO last month noted a high presence of lambda in other South American countries, including Argentina, Chile and Ecuador. And now we know he’s present in the United States
The lambda variant carries a number of mutations with suspected implications, such as potential increased transmission or possible increased resistance to neutralizing antibodies, according to the WHO. But he says the full extent of the impact of these mutations is not yet well understood and will require further study.
While there hasn’t been any clear direct data, the evidence so far doesn’t suggest lambda has a big advantage over delta, Ray says.
“The delta is clearly dominating right now. And so I think our focus may remain on the delta as a feature of a highly infectious variant. And there is some evidence that this could lead to greater severity per infection, although it’s still a developing story, ”he says.
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COVID-19 vaccines work well against variants
There is not yet complete data on the effectiveness of the vaccine against the lambda variant. But so far, studies have shown that vaccines available in the United States provide protection against major strains of the virus, including the highly transmissible delta variant.
“We know that vaccination protects people almost uniformly,” says Ray.
The vast majority of hospitalizations and deaths from COVID-19 in the United States are now unvaccinated people.
Studies have shown that vaccines are less effective at generating neutralizing antibodies against the variants of concern than against the original strain of the virus. But T cells also play an important role in the body’s immune response, and the T cell response is not measured in clinical tests for neutralizing antibodies, which means vaccines may be more effective against variants than antibody response tests alone do not suggest this.
WHO says lambda is an interesting variant. The CDC does
The WHO now assigns Greek letters to strains of the virus that are classified as variants of concern or variants of interest. A variant of concern is a variant that exhibits characteristics such as being much more transmissible or more virulent.
Their names in Greek letters indicate when they were identified as potentially significant – they are not listed in any particular alphabetical order of severity.
The alpha, beta, gamma and delta variants are all considered variants of concern by the WHO.
The WHO classified lambda last month as a global “variant of interest” – a notch below the variant of concern. This means that it has genetic changes suspected of affecting its transmissibility and disease severity, and has been identified as the cause of significant community transmission or multiple clusters of COVID-19.
The Centers for Disease Control and Prevention maintains its own list of worrying and interesting variants in the United States. Notably, lambda is not on the CDC’s list as a variant of interest, concern, or high consequence.
Ray says tracking variations is important so that we don’t get caught off guard by his sudden arrival.
“We need to be vigilant for these new variants and monitor them. Genomic epidemiology remains an important activity for us to understand this epidemic,” said Ray. “But I think right now Lambda is a variant of interest, and we’ll see if that becomes a variant of concern.”
The things we need to do to counter the new strains are the same things we already know how to do against the coronavirus – and the stakes are high because the delta is so transmissible.
This means that vaccination is more important than ever, said Ray: “As the variants become more infectious, the proportion of vaccinated people needed to control the epidemic increases. “