CHICAGO (NEXSTAR) – One person who attended a birthday and a funeral in Chicago earlier this year likely left 16 people infected with coronavirus, three of whom died, according to a Centers for Disease Control and Prevention study.

The gatherings happened about three days apart, before social distancing policies were implemented. The cases (seven confirmed and nine probable) range in age from 5 to 86 years old.

The first patient, labeled A1.1, had recently traveled out of state and had some mild respiratory symptoms, but decided to attend the funeral of a friend anyway. He hadn’t been tested at the time and didn’t know he had COVID-19, which investigators later confirmed.

The evening before the funeral, he spent about three hours with family members of the deceased friend, eating a “potluck-style” meal from common serving dishes. When he said his goodbyes, he expressed his condolences and hugged the other people at the dinner, according to the CDC.

(CDC)

Two of the family members started to experience COVID-19 symptoms between two and four days later. One of the two later died. A third person who hugged A1.1 developed suspected COVID-19 symptoms six days after the funeral.

The next day at the funeral, A1.1 had close contact with a fourth person, who also visited one of the sick family members in the hospital. That person embraced the family member without any protective gear and later developed a fever and cough believed to be from the novel coronavirus.

Three days after the funeral, still experiencing symptoms, patient A1.1 went to a birthday party attended by nine family members. A1.1 embraced everyone at the party and shared food during a three-hour span.

Seven people at the party got sick, two of whom later died despite being placed on ventilators. A home care nurse and another family member developed COVID-19 after taking care of one of the patients without using protective gear. The family member is then believed to have passed it to a home contact who didn’t go to the party.

Several days after the birthday, three of the family members went to church while experiencing symptoms; at least one person at the service who touched the same offering plate and sat one row away developed confirmed COVID-19.

The study shows how quickly COVID-19 can spread through a community, and, the CDC points out, doesn’t include any potential cases of asymptomatic infection.

“Overall, these findings highlight the importance of adhering to current social distancing recommendations, including guidance to avoid any gatherings with persons from multiple households and follow state or local stay-at-home orders,” the CDC says in the report.