As colder weather sets in, public health experts are keeping a close eye on COVID-19 variants that could spell doom and gloom this winter, just like omicron did last year. Yet these nascent variants that are rapidly spreading abroad have an evil twist that omicron lacked: an ability to evade the drugs that humans have developed to fight the SARS-CoV-2 virus.
The two subvariants of particular concern are known as BQ.1 and BQ.1.1, both off-shoots of the omicron variant BA.5 (but with several key changes.) Indeed, they seem able to evade many of the tools we have to defend against it, which could trigger a wave of hospitalizations, disabling victims with long COVID or death.
Also worrying are two other strains: one called BA.2.75.2, which seems to be spreading quickly in Singapore, India and regions of Europe; and XBB, which some research suggests is the most antibody-evasive strain tested, almost on the level of the SARS-CoV-1 virus (known then simply as "SARS") that caused an outbreak in 2003. This could make the new vaccines relatively useless (but still better than nothing.) Moreover, an outbreak caused by one of these highly drug- and antibody-resistant variants could be much worse due to many world governments performing far less testing and reduced public health surveillance compared to 2020 and 2021.
Despite some confusing remarks from President Joseph Biden, the pandemic appears far from over. The SARS-CoV-2 virus has essentially been given free rein the last several months, allowing it to mutate and evolve new ways around immunity and vaccinations. These tiny alterations are largely focused in the spike protein, the hooks surrounding the virus used to insert itself into cells and reproduce.
The difference between variants and subvariants comes down to the level of genetic changes in the virus. It appears that the adaptations necessary to evade immune detection are becoming more and more slight — and, more curiously, all the subsequent major mutations have stemmed directly from the omicron variant, which appears to be incredibly successful at reproducing already. Indeed, we may not see a major new strain any time soon because these omicron lineages are just so good at spreading, although it's difficult to predict anything with certainty.
For most of this year, an omicron subvariant called BA.5 has been largely responsible for infections, hospitalizations and death in the U.S. Together with a close relative called BA.4.6, the two subvariants make up 94 percent of cases as of October 1st, according to the Centers for Disease Control and Prevention.
Cao co-authored a paper, which has yet to be peer-reviewed, that seems to show previous infections by BA.5 and antibody drugs, including Evusheld and Bebtelovimab, aren't enough to stop a BQ.1 infection.
But that could change in the coming weeks. BQ.1 and BQ.1.1 are both spreading extremely fast in parts of Europe. According to Cornelius Roemer, a viral evolution expert at the University of Basel, the number of BQ.1.1 infections has been doubling every week. That kind of exponential growth is sure to drive the variant to becoming dominant globally in short order.
"The degree of immune escape and evasion is amazing right now, crazy," Yunlong Richard Cao, an immunologist at Peking University in Beijing, told Nature this week. Cao co-authored a paper, which has yet to be peer-reviewed, that seems to show previous infections by BA.5 and antibody drugs, including Evusheld and Bebtelovimab, aren't enough to stop a BQ.1 infection.
"Such rapid and simultaneous emergence of multiple variants with enormous growth advantages is unprecedented," Cao and his colleagues warned in the study. "These results suggest that current herd immunity and BA.5 vaccine boosters may not provide sufficiently broad protection against infection."
Meanwhile, BA.2.75.2, an offshoot of the Centaurus omicron subvariant, also shows stark ability to evade antibodies. While it isn't a big deal in the West yet, it is seemingly spreading quickly in India. Some research from Sweden, which also isn't yet peer reviewed but is in line with Cao's research, described BA.2.75.2 as "the most neutralisation resistant variant evaluated to date."
And then there's XBB, which Cao has described as "the most antibody-evasive strain tested." It combines two different omicron lineages (BJ.1 and BM.1.1.1) to make something so good at evading immunity (either from previous infections or vaccines) that it's close to SARS-CoV-1. It "could cause significant immune escape at a scale never seen before," Cao and his colleagues wrote.
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The new vaccines may still protect some against these variants, such as preventing hospitalization or death, but it may not be enough to stop an infection. How that will translate to rates of long COVID has yet to be seen, but already the debilitating condition has put millions out of work.
Not only are variants changing, so are the symptoms. Recent reports from the U.K. suggest that a sore throat is now the dominant symptom of COVID infection, rather than fever or loss of smell.
"Fever and loss of smell are really rare now — so many old people may not think they've got COVID," Professor Tim Spector, co-founder of the Covid ZOE app, told The Independent. "They'd say it's a cold and not be tested."
Whatever this winter throws at us, we're going to need all the tools at our disposal — including vaccines, masks and improved ventilation systems — to keep devastating COVID infections at bay.
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