Washington — A patient who had recently been vaping has died in hospital in the Midwestern US state of Illinois after developing severe respiratory illness, the local health authority said Friday.

The adult, whose age and gender have not been released, was one of 153 people across 16 states sickened by the illness since the end of June, according to figures released Wednesday by the Centers for Disease Control and Prevention.

The cause has not been determined but all had recently used e-cigarettes, medics said.

"The severity of illness people are experiencing is alarming and we must get the word out that using e-cigarettes and vaping can be dangerous," said Illinois health department director Dr Ngozi Ezike.

"We requested a team from the Centers for Disease Control and Prevention to help us investigate these cases and they arrived in Illinois on Tuesday."

Many of the patients had recently vaped cannabis, the CDC said, though no specific product has even been identified, let alone blamed, for the illness, in any of the cases. AFP