Enlarge / The Centers for Disease Control and Prevention (CDC) headquarters stands in Atlanta, Georgia, on Saturday, March 14, 2020. (credit: Getty | Bloomberg)

The tally of COVID-19 cases linked to a conference of disease detectives hosted by the Centers for Disease Control and Prevention in April has reached at least 181, the agency reported.

Roughly 1,800 gathered in person for this year’s annual Epidemic Intelligence Service (EIS) Conference, which was held on April 24 to 27 in a hotel conference facility in Atlanta where the CDC’s headquarters are located. It was the first time the 70-year-old conference had in-person attendees since 2019. The CDC agency estimates an additional 400 attended virtually this year.

By the last day of the event, a number of in-person attendees had reported testing positive for COVID-19, causing conference organizers to warn attendees and make changes to reduce the chance of further spread. That reportedly included canceling an in-person training and offering to extend the hotel stays of sick attendees who needed to isolate.