CHICAGO — Illinois Gov. J.B. Pritzker says an infant with COVID-19 has died and an investigation is underway to determine the cause of death.

Officials didn’t release other information about the infant, who was from Cook County, which includes Chicago, including whether the child had other health issues.

The risk of death and severe illness from COVID-19 is greater for older adults and people with other health problems. In most cases, the virus causes mild or moderate symptoms, which can include fever and cough but also milder cases of pneumonia, sometimes requiring hospitalization.

Children have made up a small fraction of coronavirus cases worldwide. A letter published in the New England Journal of Medicine by Chinese researchers earlier this month reported the death of a 10-month-old with COVID-19. The infant had a bowel blockage and organ failure, and died four weeks after being hospitalized.

Separate research published in the journal Pediatrics traced 2,100 infected children in China and noted one death, a 14-year old. The study found less than 6% of children were seriously ill.

(AP)