The CDC is worried about a mpox rebound and urges people to get vaccinated

A sign for monkeypox vaccinations is shown at a vaccination site in Miami Beach, Fla. (Lynne Sladky/AP)

Lynne Sladky / Lynne Sladky

When the JYNNEOS vaccine for mpox rolled out last summer, health officials believed it would work. It was an educated guess, at the height of a public health emergency, based mostly on data from animal studies.

Now, after 1.2 million doses have been given in the U.S., the Centers for Disease Control and Prevention has real-world evidence that the mpox vaccines are working to prevent disease.

Three new studies show that two doses of the JYNNEOS vaccine are somewhere between 66% and 86% effective at preventing mpox among people at risk. The research was published on Thursday in the New England Journal of Medicine and the CDC’s Morbidity and Mortality Weekly,