An uncommon virus — enterovirus 68 — is causing the illnesses. Centers for Disease Control and Prevention officials said Friday that 160 lab-confirmed cases were reported in the 22 states. On Tuesday, the CDC's count was 130 cases in 12 states.
The newest states are California, Connecticut, Georgia, Michigan, Minnesota, Montana, Nebraska, New Jersey, Virginia and Washington.
The virus can cause mild to severe illness, with the worst cases needing life support for breathing difficulties. Kids with asthma have been especially vulnerable. No deaths were reported.
The strain is not new but rarely seen, and only a small number of labs can test for it. A spike in cases was first identified in mid-August.