Omicron offshoot XBB.1.5 could drive new Covid-19 surge in US

Omicron offshoot XBB.1.5 could drive new Covid-19 surge in US

 

Last week, the US Centers for Disease Control and Prevention’s Covid-19 variant dashboard revealed a new dark horse that could soon sweep the field of subvariants causing new infections: XBB.1.5.   Virologists and epidemiologists say this Omicron sublineage has features that give it the potential to drive a new surge of Covid-19 cases in the US, although it’s still unclear how large that wave will be and whether it could send many more people to the hospital.   In terms of immune evasion, Columbia University microbiology and immunology professor Dr. David Ho says recent variants like XBB, XBB.1, BQ.1 and BQ.1.1 have shifted as far away from the antibodies we have made to use against them as the original Omicron variant was from the Covid-19 viruses that preceded it roughly a year ago.   In recent lab studies, Ho found that XBB.1 was the slipperiest of them all. It was 63 times less likely to be neutralized by antibodies in the blood of infected and vaccinated people than BA.2 and 49 times less likely to be neutralized compared with BA.4 and BA.5.   He calls these levels of immune evasion “alarming” and said they could further compromise the efficacy of the Covid-19 vaccines. His findings were recently published in the journal Cell.   Ho said Monday that XBB.1.5 was the same story in terms of antibody evasion as XBB.1, which means it has the potential to escape the protections of vaccinations and past infections. It’s also resistant to all current antibody treatments, including Evusheld.   In addition to being highly immune-evasive, XBB.1.5 has an additional trick up its sleeve that seems to be helping to fuel its growth. It has a key mutation at site 486, which allows it to bind more tightly to ACE2, the doors the virus uses to enter our cells.   Still, experts say it’s hard to know how much of XBB.1.5’s growth can be attributed to properties of the virus and how much simply to good timing. Coming out of the holidays, during which time people were more likely to travel and socialize, gives any infection – whether it’s the flu, Covid-19 or RSV – more room to run.   Michael Osterholm, who directs the University of Minnesota’s Center for Infectious Disease Research and Policy, notes that the updated boosters should provide some protection, even against this highly immune-evasive strain.   “They still provide a level of immunity that may not prevent you from getting infected but may have a significant impact on whether or not you become seriously ill and die,” he said. “Right now, the most recent data we have shows that for those who have the bivalent vaccine, they have a three-fold lower risk of dying than those who don’t.”