“Nothing unexpected here,” Department of Public Health Commissioner Dr. Allison Arwady said at a news conference. “No sign of a ‘superspreader event’. But clearly with hundreds of thousands of people attending Lollapalooza we would expect to see some cases.”

The four-day music festival, which started two weeks ago, drew about 385,000 people to a lakefront park. Critics questioned holding the event during the pandemic. Footage showed tightly packed crowds at concerts and on public transportation with few masks in sight. Last year’s festival was canceled because of COVID-19.

But Mayor Lori Lightfoot and other officials have defended the decision, saying there were safety protocols in place. Festival goers had to show proof of vaccination or a negative COVID-19 test and city officials said about 90% were vaccinated.

Arwady said the number of positive cases included those who tested positive after or during Lollapalooza, which could include people who might have arrived already infected. For instance, 13 Chicago residents who tested positive reported attended Lollapalooza on or after the day their symptoms began.

She said the city was still investigating cases, but did not expect it to make a major impact on COVID-19 infection rates.

“We would have seen a surge if we were going to see a surge at this point,” she said.

Among those who tested positive, city officials said 138 were Illinois residents from outside Chicago, 58 were from the city and seven were from out of state. Nearly 80% of those who tested positive were under 30, and about 62% were white, Arwady said.