They investigate possible Mexican variant of covid-19 2:44
(CNN) – The US Centers for Disease Control and Prevention (CDC) said this week that they had designated a variant of coronavirus that was first seen in India as a “variant of interest,” adding it to the growing collection of viral variants you are keeping an eye on.
Vaccine manufacturers are so concerned about the possibility of new variants escaping the protection offered by immunization that they are already testing booster doses and adjusting their vaccine formulations to specifically target some of the more worrisome variants.
WHO: Indian variant of covid-19 is worrying 0:53
And doctors around the world warn that even more variants will emerge as the virus continues to evolve within the bodies of the tens of millions of people who are becoming infected.
The CDC has designated three levels of variants: variants of interest, which have the potential to be dangerous but have not yet caused much disruption; worrisome variants, which are more contagious, evade some treatments, cause more serious illness, or pass diagnostic tests; and high-risk variants, which significantly evade the effects of vaccines or treatments.
“Currently, there are no variants of SARS-CoV-2 that are elevated to the high-risk level,” says the CDC.
Here’s what we know about variants of interest and variants of concern:
Variants of interest
In laboratory tests, all CDC-classified variants of interest have been found to resist immune attack in blood drawn from people who have recovered from COVID-19, as well as from people who have been vaccinated.
B.1.526: First seen in New York last November, B.1.526 has what is called a 484 mutation. To understand the variants, it is important to first understand the mutations that characterize them. The E484K mutation is a change in the part of the virus called the spike protein, which is the knobby structure that protrudes from the surface of the virus. The change, in a region called the receptor-binding domain, makes the virus more easily adhere to the cells it infects and also makes the virus less recognizable to the immune system.
Evidence shows that it can theoretically withstand the effects of Eli Lilly’s combined monoclonal antibody treatment, although it’s unclear whether that translates into treatment failure, the CDC says. Regeneron’s antibody cocktail treatment for COVID-19 appears to work against him. It has also been shown to resist immune attack in blood drawn from people who have recovered from COVID-19, as well as people who have been vaccinated. It represented just under 9% of the samples sequenced in the US as of April 10.
New research from the CDC released this week shows that it is not associated with a more serious infection or an increased risk of reinfection.
B.1.526.1: Also seen for the first time in New York, B.1.526.1 has a different pattern of mutations compared to the original sequenced strain from China, including one called L452R that appears to help the virus infect cells more easily while at the same time, makes it difficult for antibodies to attack.
B.1.617: First seen in India in February, this is sometimes misleadingly called a “double mutant” because it has an L452R mutation and a 484 mutation, although it is not exactly the same 484 mutation seen in other worrisome variants. The WHO has designated B.1.617 and its sublineages as a “variant of concern”.
B.1.617.1, B.1.617.2 and B.1.617.3: All were seen for the first time in India and were circulating before B.1.617. They all have the same mutations as B.1.617, plus a few extras.
Although Indian officials have said that these new variants are driving the surge in coronavirus cases that is currently overwhelming the country’s hospitals, the director of India’s National Center for Disease Control, Sujeet Singh, said last week. missing evidence. “We have not yet been able to fully establish the epidemiological and clinical correlation,” Singh said Wednesday.
British health officials, however, updated B.1.617.2 to a worrying variant on Friday due to its rapid spread there. “Currently, there is insufficient evidence to indicate that any of the variants recently detected in India cause more serious disease or make currently implemented vaccines less effective,” Public Health England said in a statement.
Dr Chris Whitty, England’s chief medical officer, said during a Royal Society webcast on Thursday that the B.1.617 variants probably fall in the middle in terms of danger between B.1.1.7, which seems almost completely susceptible. vaccines and treatments, and B.1.351, which has been documented to infect people who have recovered from infection with previous variants of the coronavirus, and also partially evade the protection that vaccines offer.
B.1.525: First seen in the UK and Nigeria, it carries the E484K mutation. It has been found in less than 1% of samples tested in the United States. That surveillance is incomplete. This week, CDC Director Dr. Rochelle Walensky said the United States is now sequencing about 8% of the country’s roughly 450,000 weekly COVID-19 cases.
Q.2: Circulating in Brazil since last year, this variant also carries the worrisome E484K mutation and has not been found widely throughout the world.
Covid-19: mortality in South America is the worst in the world 0:47
Worrisome variants
They are defined by the CDC as variants for which there is evidence that they are more communicable, cause more severe disease, do not respond to treatment, evade the immune response, or are not diagnosed by standard tests.
B.1.1.7: Variant B.1.1.7 first seen in the UK has been shown to be at least 50% more transmissible and some evidence suggests that it may cause more serious disease, although at least one study found no evidence of this. It carries 23 mutations, including one called N501Y that increases transmission.
It represented 60% of all samples tested in the US as of April 10, according to the CDC. The University of Washington Institute for Health Metrics and Evaluation estimates that it now accounts for virtually all new infections in 23 states.
It is completely susceptible to monoclonal antibody treatments and vaccines.
“We are confident that the vaccines that are currently less available in the UK work against that, for all practical purposes,” said Whitty.
A team in the Gulf state of Qatar tested the effectiveness of the Pfizer / BioNTech vaccine during a time when Qatar was seeing the circulation of variant B.1.351 first identified in South Africa and variant B. 1.1.7 first identified in the UK.
“The estimated effectiveness of the vaccine against any documented infection with variant B.1.1.7 was 89.5% at 14 days or more after the second dose. The effectiveness against any documented infection with the B.1.351 variant was 75%, ”the researchers wrote in a letter to the New England Journal of Medicine.
B.1.351: First seen in South Africa, this variant has the E484K mutation that is linked to immune escape and the N501Y mutation that is suspected to help other variants be more contagious. It has been shown to be 50% more transmissible and evades Lilly’s dual monoclonal antibody treatment, but not others. Blood tests and use in real life suggest that it can infect people who have recovered from the coronavirus and also people who have been vaccinated against covid-19.
Vaccine manufacturers trying to get ahead of newer variants by developing booster vaccines have focused on B.1.351, as it is the variant that scientists fear most could bypass the protection of the vaccine. Moderna said Wednesday that a booster shot of her vaccine boosts the immune response against B.1.351 and another variant, P.1.
The good news is that it does not appear to cause a more serious illness, as was initially feared, said Dr. Salim Abdool Karim, director of the Center for AIDS Research Program in South Africa.
“It turns out that in South Africa the evidence we have now is that it is not more severe,” he told the Royal Society briefing. However, it eludes the human immune response to a significant degree. It spread rapidly through South Africa, Karim reported, accounting for 11% of the viruses sequenced in October and 87% of the samples sequenced in December.
“If you were infected with the virus before, this time you are not fully protected,” Karim said. “About half of the people who were exposed were re-infected.”
Q.1: First seen in Brazil, it also has the E484K and N501Y mutations, with more than 30 more. It has been shown to circumvent the effects of Lilly’s monoclonal antibody treatment, but not one manufactured by Regeneron. Blood tests show that it could escape both natural and vaccine-induced immune responses.
B.1.427: First seen in California, this one has the L452R mutation. The CDC says it is about 20% more transmissible and may partially resist the effects of Lilly’s monoclonal antibody treatment. Blood tests suggest that it could re-infect people who have been vaccinated against covid or who have recovered, but that has not yet been proven in real life.
B.1.429: Another so-called California variant, this one has the L452R mutation along with others and is similar to B.1.427 in other respects. It represented 4% of the samples sequenced nationwide as of April 10.
Last month, a team at the University of California, San Francisco conducted an in-depth sequencing of more than 2,000 samples from people who tested positive for coronavirus in California. They found that variants B.1.427 / B.1.429 increased from representing no sample in September to representing half of all samples taken in January.
They seem to replicate better in the noses of infected people, something that could explain their faster spread, the UCSF team, led by Dr. Charles Chiu, reported in the journal Cell. But they are not as transmissible as variant B.1.1.7.
CNN’s Virginia Langmaid contributed to this story.
