Cook County public health officials confirmed Wednesday that a 9-month-old baby whose March death garnered the nation’s attention as possibly the youngest novel coronavirus victim did, in fact, die from complications related to COVID-19.

The Cook County Medical Examiner’s Office reported that Joseph Myles died March 23 due to viral pneumonia that was caused by COVID-19 and another strain of coronavirus known as NL-63, which primarily affects children or people with underlying conditions, according to a study published by the National Institutes of Health.

“A family member found Myles unresponsive … and notified authorities,” according to a medical examiner’s press release. “The family reported that Myles had a history of a cold and cough.”

Nasal swabs taken on the day of Myles’ death, and in the days following, were tested by the Illinois Department of Public Health and the Centers for Disease Control.

Although initial test samples gave conflicting results, the CDC ultimately confirmed COVID-19 was present, along with the other coronavirus strain, NL-63.

Myles was the first known infant to die from COVID-19, according to health officials who announced his death, which was suspected early on to be from the novel coronavirus.

“There has never before been a death associated with COVID-19 in an infant,” said IDPH Director Dr. Ngozi Ezike at the time. “A full investigation is underway to determine the cause of death. We must do everything we can to prevent the spread of this deadly virus.”

Myles is one of more than 6,000 Illinoisians to die from coronavirus. The second youngest Cook County victim was a 12-year-old boy, Ernesto Guzman, who died in May.

Mariah Woelfel is a general assignment reporter and producer at WBEZ.