A birthday party in Pasadena, California led to a cluster of coronavirus cases.

The Pasadena Public Health Department said that a “large number” of extended family members and friends attended the event. The party happened after the city announced its stay-at-home directive in March, CNN reports.

One patient who attended the party was coughing and hadn’t worn a face mask, while other event guests also hadn’t covered their face or practiced social distancing. “As a result, COVID-19 spread among party attendees,” department health officials said.

Through contact tracing, investigators discovered over five confirmed COVID-19 cases stemming from the party and “many more ill individuals.”

“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,” Dr. Matthew Feaster, an epidemiologist with the department, said.

“Although we are moving forward with small modifications to the Safer at Home Order, gatherings of people who do not live in the same household are still prohibited,” Dr. Ying-Ying Goh, director and health officer of the department, said. “The virus remains highly contagious. Social distancing, frequent hand washing, and wearing face coverings remain our best defenses against the further spread of Covid-19 in our community.”

On May 8, California Gov. Gavin Newsom relaxed some of the state’s social distancing policies, allowing some retails shops to reopen. Stores include compliant clothing stores, bookstores, music/toy stores, sporting goods stores, and florists, which can all begin offering curbside services. Some beaches, like in Laguna Beach and San Clemente, have permission to open in a limited fashion.