By Alice Park January 10, 2025 9:41 AM EST N orovirus is surging across the U.S. , with case numbers higher now than they've been at the same time in more than a decade, according to the U.S. Centers for Disease Control and Prevention (CDC). There is no antiviral treatment for the miserable but thankfully short-lived illness, and no vaccine—yet. But scientists at Moderna are in the late stages of testing what could be the first such shot, using mRNA technology against the virus. Here’s what to