Importantly, however, Luban said there was no reason to believe that XBB would cause more serious disease than other variants.
“So far, I don’t think there’s any clear evidence that any of these mutants escape the protection against severe disease that vaccines offer,” he said. “So far, vaccines are still able to prevent severe disease,” he said, for people without symptoms that would expose them to the disease.
As with other recent variants, immunocompromised people face greater risk, and the monoclonal antibodies used to treat them do not work against modern variants, including XBB. This eliminated an important tool for treating some of the most vulnerable patients.
Dr. Andrew Pekoz, professor of molecular microbiology and immunology at the Bloomberg School of Public Health at Johns Hopkins University, said a bigger concern than the increased presence of a particular variant is the simultaneous circulation of so many different variants. is the fact that The US Centers for Disease Control and Prevention has listed 17 variants circulating in the country as of December 24th.
“It’s like simmering stew. You never know when something new pops up,” says Pekosz.
When Delta arrived in the United States in the summer of 2021, the Greek-named variant first entered the common vocabulary, dashing hopes that the coronavirus would go away. Omicron then charged around Thanksgiving that year. It was so contagious that it became dominant within days. Since then, Omicron has taken hold, but morphed into numerous variants with alphabet soup names such as BA.5 and BQ.1.1.
Another offshoot of Omicron, XBB, was first noted by the World Health Organization in early October and appeared in the United States around mid-November. As of last week, it accounted for 18% of cases nationwide.
XBB now produces its own subvariants XBB.1 and XBB.1.5.
XBB doesn’t appear to cause much serious illness or death, but little is known about the effects of XBB.1 and XBB.1.5 detected in the Northeast, says Rajendram, associate director of research at New York University. Rajnarayanan said. Institute of Technology, Jonesboro, Arkansas, Campus.
“Most of the data we have is from the UK or other countries because of the wave ahead of us.” Rajinarayanan Said.the exception is XBB.1.5 originated in the United States and has no international standard. data.
In a Dec. 23 online column, Dr. Eric Topol, executive vice president of Scripps Research in La Jolla, Calif., said the arrival of XBB.1.5 in New York coincided with a significant increase in hospitalizations in the state. I pointed out that I did.
“Of course, other factors may have contributed, such as weakened immunity, indoor/holiday gatherings, cold weather, and lack of mitigation. [COVID-19] The hospitalization rate is the highest since late January,” he wrote. “So I’m not sure how much this is driven by XBB.1.5, but it doesn’t look favorable.”
Massachusetts is also seeing an increase in hospitalizations for COVID-19. That number has increased steadily since Thanksgiving, and on December 19th he reached 914. UMass’s Luban said many factors contributed to the trend, including the spread of illness during holiday gatherings, at a time when most people stopped wearing masks.
And as more people get sick, the small percentage that need hospitalization could add up to a large number, he said.
“The increase in hospitalization rates we’re seeing is likely due to a combination of social factors and the fact that the virus is more contagious,” Luban said.
The emergence of XBB is part of a process that has been ongoing since the pandemic began nearly three years ago, Luban said. Coronaviruses evolve to evade the defenses people develop through vaccination and infection. In recent months, the virus has spawned many variants and has seen little traction, but with XBB, the virus seems to have affected prescriptions that spread particularly well.
So far, there are no indications that XBB causes serious illness, but Luban warns: Any mutant could develop the ability to overcome the part of the immune system that protects against severe disease, he said.
As usual, experts urged people to get booster shots. appears to be particularly effective against XBB.
“Right now, the biggest drivers of hospitalization are immunocompromised individuals,” said Pecos of Johns Hopkins University. “We really need boosters these days, ideally bivalent boosters. That is especially to increase protection from hospitalization.”
So far, only 11.8% of Boston residents have received Omicron-specific bivalent boosters, according to the Boston Public Health Commission.
Vaccination does not prevent all infections, but wearing a high-quality mask can prevent infection. New York Institute of Technology’s Rajinarayanan said he was “heartened” to learn that Boston schools are considering a temporary mask mandate.