The highly contagious disease can cause brain damage and even death. State health officials are warning unvaccinated people who were at the Denver airport and Children's Hospital.
The WHO has classified the JN.1 coronavirus strain as a 'variant of interest' and said current evidence shows risk to public health was low from the strain.
Medical experts are alarmed by a simultaneous rise in recent hospitalizations for other respiratory illnesses like RSV and the flu, with the CDC issuing an 'urgent need' to raise vaccination coverage against all three viruses nationwide.