AScientists are trying to track down the spread of a new, more contagious coronavirus variant around the world – finding more cases in the United States and elsewhere this week – they are also watching another mutation with possible bigger implications for how good Covid- 19 vaccines work.
The mutation, identified in a variant first seen in South Africa and seen separately in another variant in Brazil, changes part of the virus that trains your antibodies of your immune system to recognize after you infected or vaccinated. Laboratory studies show that the change may make human antibodies less effective at neutralizing the virus. It seems that the mutation can help the virus to disguise part of its appearance, so that the pathogen can slide more easily against immune protection.
It is not the case that the mutation will render existing vaccines useless, scientists emphasize. The vaccines approved so far and those in development produce a polyclonal response, producing numerous antibodies that occur on different parts of the virus. Changes to any of the target sites raise the possibility that the vaccines will be less effective, and not that they will not work at all.
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“With one mutation or even three mutations, the antibodies are expected to still recognize this variant, although they may not recognize it as well as other variants,” says Ramón Lorenzo-Redondo, a molecular virologist at the Feinberg School of Medicine of the North-West University.
In essence, the mutation is getting attention because it is more likely to have an effect on vaccines than other mutations that have arisen, although scientists are still trying to test the hypothesis. It is suspected that the more contagious variant causing global alarms, first seen in the UK and referred to as B.1.1.7, has mutations that greatly affect the vaccines.
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“We need to monitor for these mutations,” said Jesse Bloom, an evolutionary virologist at Fred Hutchinson Cancer Research Center, who, along with colleagues, published an article this week on this particular mutation, known as E484K.
But Bloom added that he believes the virus will have to pick up multiple mutations – and especially mutations at specific sites, and not just any changes – to seriously affect the effectiveness of the vaccine, which is likely to take some time.
“I’m quite optimistic that immunity will not even suddenly fail us with these mutations,” Bloom said. “It can be gradually defended, but it will not disappoint us at least in the short term.”
Scientists do think that the coronavirus could eventually change so much that the immunity provided by vaccines could be threatened, a process that will increase as the number of people protected against the virus, whether through vaccination or infection, increases and the evolutionary pressure in turn increases. But they still expect it to take years and that vaccine manufacturers, when it does, can adapt their designs to suit the newer variant, a process that some companies say will only take weeks.
The SARS-CoV-2 coronavirus, which causes Covid-19, mutated like the other viruses as it spread. Many of the mutations do nothing, and some even hinder the virus’ attempt to replicate and spread. But so often a random mutation gives the virus an evolutionary advantage, and the variant can then become dominant. Early in the pandemic, a mutation known as D614G helped the coronavirus spread more easily, and variants with the mutation quickly overtook others worldwide.
B.1.1.7, which has since spread to other parts of the world, appears to be even more contagious, and according to some estimates it is 50% more transmissible. One of the mutations, called N501Y, improves how well the virus’ peak protein can attach to a receptor called ACE2 on human cells, making it more likely that the virus can successfully infect cells and that the virus passes from person to person.
The same N501Y mutation is also present in the variant identified in South Africa, although the two variants developed independently. “Public health authorities are trying to stop people from using terms like ‘UK variant’ or ‘South African variant’, just as they are discouraging people from tying SARS-2 by name to China or Wuhan. ‘ because we do not want to stigmatize where these variants have been identified, “Maria Van Kerkhove, of the World Health Organization, said on Tuesday.” This applies to any identified virus. “
The inclusion of N501Y apparently also helps to spread the variant faster in South Africa, but the variant also has the E484K mutation, in contrast to the variant that first appeared in the United Kingdom. mutations in the same part of the virus have previously occurred during the pandemic, the specific E484K mutation now attracts more importance in part because it spread in this variant across South Africa and began to appear by travelers elsewhere, including Japan, Norway and the United Kingdom
The E484K change occurs on a part of the vein protein called the receptor binding domain, which plays an important role as the virus attaches to ACE2 and is an important target for antibodies. As laboratory studies have shown, antibodies do not recognize variants with E484K as well as other forms.
Research by Bloom and colleagues this week further added to the evidence. In their study, which looked at how antibodies in humans recovering from Covid-19 performed against different variants, the scientists found that mutations such as E484K had the greatest impact on the antibodies’ ability to block the virus. , and some people experience more than a 10-fold decrease in neutralization compared to the variant. The researchers call the location of the E484K mutation “the place where most viral mutations are concerned.” (However, there was variability among the samples; some people could only neutralize the variant well, and mutations in other places had more of an impact than E484K had for some people.)
Bloom’s study focused on people recovering from an infection, not those who had been vaccinated; researchers around the world are investigating how well current vaccines can withstand different variants.
But despite what he and colleagues found about E484K, Bloom noted that the mutation only reduced the neutralizing activity and did not eliminate it. Current vaccines, meanwhile, have been shown to elicit strong immune responses. “I am confident that current vaccines will be useful for some time to come,” Bloom wrote in a letter. Twitter thread set out the research.
According to scientists, the spread of B.1.1.7, the variant first seen in the UK, although there are no more serious cases of Covid-19, if it causes more cases because it spreads more easily, it will leading to more hospitalizations and deaths. It is also probably more difficult to control than other variants and raises the threshold of the percentage of the population that needs to be protected to achieve herd immunity.
“The variant is really a big problem,” said Marc Lipsitch, an epidemiologist at Harvard’s TH Chan School of Public Health.
Lipsitch said the U.S. should focus its efforts on curtailing the variant, including by sequencing more samples of patients to identify cases and directing the detection and quarantine campaigns for contacts to try to zoom it out.
‘To the extent that we can find it and stop the spread by preference, it will not be perfect, it will not be perfect for a long time, but all we can do to slow down the spread of this new virus will be “facilitates control and helps us in the race to get more people vaccinated before it becomes more common,” he said.