CDC investigating possible mpox resurgence amid dozens of new cases nationwide

The U.S. Centers for Disease Control and Prevention said Wednesday it was working with multiple health departments to investigate new mpox cases around the country, less than a month after officials had hailed the weekly pace of new infections slowing to zero nationwide.

News of the CDC's investigations come a day after Chicago health officials warned they had tracked a resurgence of infections from mpox, formerly called monkeypox, many among fully vaccinated residents.

"Most weeks we didn't see a single mpox case, maybe one or two in a higher week. But just these last couple of weeks we saw two, then five, now another six coming in," Dr. Allison Arwady, commissioner of Chicago's health department, said Tuesday.