As the US gears up for another wave of COVID-19 infections, scientists are concerned about the sudden and rapid spread of new Omikron subvariants. Data from the U.S. Centers for Disease Control and Prevention (CDC) published last week shows that the BQ.1 and BQ.1.1 subvariants now account for more than ten percent of all cases, while the BF.5 subvariant still accounts for more than ten percent of all cases. once five percent of American patients are found.
According to John Swartzberg, an infectious disease and vaccinology expert at the School of Public Health at the University of California at Berkeley, the situation could “turn around in a matter of weeks” if these subvariants continue to spread at this rate. “One or all three strains could displace the existing Omikron subvariant BA.5 as the most widespread SARS-CoV-2 strain.” (Globally, experts are also concerned about other Omikron sub-variants, such as XBB.)
What exactly are these sub-variants and how do they differ from previous strains? We summarize the most important facts.
What are ‘B1.1’, ‘Q.1’, ‘BQ’ and ‘BF.7’?
The three Omikron sub-variants currently spreading rapidly in the US are all descendants of BA.5, the sub-variant that is still responsible for about two-thirds of all COVID-19 infections in the US. As before by National Geographic was reported, all Omikron descendants are of concern because they share a number of characteristics: they spread more easily than previous variants and can evade accumulated antibodies against COVID-19.
According to Stuart Ray, an infectious disease expert at Johns Hopkins University in Baltimore, Maryland, BQ.1, BQ.1.1 and BF.7 are of particular concern because these subvariants have developed mutations in the protein receptors on the spikes of the brain. coronavirus, a component fundamental to its ability to evade the human immune system.
Ray sees these subvariants as examples of a phenomenon called “convergent evolution,” a process in which different organisms go through the same evolution independently of each other. “Changes in that area of the spikes occur across numerous lineages, suggesting that these mutations confer major evolutionary benefits,” he says. “Even though the tribes develop independently of each other, they come up with the same solutions to the same challenges.”
Are the new sub-variants more dangerous?
While these subvariants are believed to be better at evading antibodies, there is little evidence that they cause a more severe disease course than previous strains.
Scientists are concerned that the new subvariants also appear to be good at bypassing drugs given to people with weak immune systems or those vulnerable to a severe course of the disease. White House chief medical adviser Anthony Fauci told CBS News that BQ.1.1. ostensibly capable of ‘evading important monoclonal antibodies.’ These antibodies are used in drugs like tixagevimab and are designed to attach to the same region of protein receptors on the spikes of the virus where previous mutations led to new subvariants. More research is needed to confirm this problem.
Ray points out that it is difficult to compare the pathogenicity of the new subvariants with that of previous strains, given the level of immunity that has built up in the population. Thus, it is entirely possible that these subvariants would have done much more damage if they had surfaced before the introduction of current vaccines against COVID-19.
“If people don’t maintain their immunity with the help of vaccines, we could see an increase in the number of serious cases,” he says. Even with mild illnesses, there is every reason to be concerned about a recurrence of cases, as these types of repeat infections are associated with cardiovascular disease, brain disorders and post-COVID-19 complications. “Vaccination is the way to maintain immunity, and our best solution now is bivalent vaccines.”
Protection against sub-variants
Sufficient data are not yet available to answer the question whether bivalent vaccines – new versions of the original vaccines that specifically protect against the Omikron sub-variants BA.4 and BA.5 – also protect against the new sub-variants. So why are most experts quite optimistic? Ashish Jha, White House COVID-19 Coordinator, explained at a press conference last week that the three new subvariants are all descended from the Omikron subvariant BA.5.
“That means that our updated bivalent vaccines should provide a much higher degree of protection than the original vaccine prototype would have afforded,” he says. “We will, of course, investigate exactly how much protection is involved, but I am confident that our modified vaccines will continue to work well, especially against a serious course of disease.”
Philip Chan, an assistant professor of medicine at Brown University in Providence, Rhode Island, believes the new bivalent boosters are especially welcome. He points out that most experts believe that the original vaccines still offer protection against severe disease and hospitalization, as is the case with variants that emerged during the pandemic.
What now?
Most experts believe that the new sub-variants make it clear that vaccines and mask wearing are still very important – and may become even more important if monoclonal antibodies are ever found not to work well against the latest versions of the coronavirus.
“What these new mutations are telling us is that the virus isn’t done with us yet,” Swartzberg says. Although no one can predict how the virus will develop further, he thinks we can assume that the number of cases of disease in the US will rise sharply in the next six to eight weeks.
“I’m sure the calm period we’re going through right now won’t last until after Thanksgiving.” [24 november],’ he says. “We should do everything we can to protect ourselves, our families and our community from new infections.”
This article was originally published in English on nationalgeographic.com