A COVID-19 patient in Pasadena infected at least four others at a large birthday party after the city issued its safer-at-home order in March, officials said Saturday.

That patient neither wore a mask nor kept their distance from others while coughing at a party attended by a “large number of extended family members and friends” after March 22, officials said.

At least four other attendees were diagnosed with COVID-19, and “many more” became sick, according to the city.

All those involved have survived but remain “very ill,” city spokeswoman Lisa Derderian told KTLA.

The city did not specify when or where the event took place. Authorities provided no further details about the patients.

Officials said they recently learned of the cluster of cases through contact tracing conducted by the local health department.

“This is an example of how good contact tracing can identify disease clusters and tell us more about the spread of disease in our community,” Pasadena Public Health Department epidemiologist Dr. Matthew Feaster said in a statement from the city.

Authorities shared information about the cases Saturday in hopes of persuading residents to avoid gatherings this Mother’s Day weekend.

Derderian said people shouldn’t feel guilty about visiting their families.

“Go virtual this Mother’s Day unless it’s with members already in your immediate household,” she advised.

As of Saturday, the city of Pasadena has confirmed 65 deaths related to COVID-19.

Editor’s note: A city representative previously said the index patient in the party marked the first case confirmed in Pasadena but later issued a correction. This post has been updated.