In Europe, the Omicron subvariants are powering a spike in cases of about 25%, though Dr. Michael Ryan, the executive director of WHO’s Health Emergencies Program, has said that number may actually be higher, given the “almost collapse in testing.” BA.5 is on the march in China, ratcheting anxieties that major cities there may soon re-enforce strict lockdown measures that were only recently lifted. And the same variant has become the dominant strain in the United States, where it accounted for 65% of new infections last week, according to the Centers for Disease Control and Prevention (CDC)…

What makes BA.5 different? Eric Topol, a cardiologist and professor of molecular medicine at Scripps Research, has called BA.5 “the worst version of the virus we’ve seen.” He explained in a recent newsletter: “It takes immune escape, already extensive, to the next level, and, as a function of that, enhanced transmissibility,” well beyond earlier versions of Omicron.

In other words, BA.5 can easily evade immunity from previous infections and vaccines, increasing the risk of reinfection. Though the variant does not appear to lead to more severe illness, in an interview with CNN on Monday, Topol said that given the extent of BA.5’s immune evasion, he expects to see an escalation in hospitalizations, as we’ve seen in Europe and elsewhere that the variant has taken root. “One good thing is it doesn’t appear to be accompanied by the ICU admissions and the deaths as previous variants, but this is definitely concerning,” he added.