By Lauren del Valle and Amir Vera, CNN

(CNN) -- Three people have tested positive for coronavirus on Friday after taking a Delta Air Lines flight from Atlanta to Albany, New York.

Flight 4815 left on July 6, a release from the Rensselaer County Health Department said.

The passengers were not symptomatic on the flight, but began showing symptoms on July 7.

"We have been made aware of three customers who tested positive for Covid-19 and recently traveled on Endeavor from Atlanta to Albany. We are following the guidance of local healthcare officials and the Centers for Disease Control and Prevention. The health and safety of our customers and crews is our top priority," Delta spokesman Anthony Black told CNN in an email.

Delta is in contact with regional CDC officials and has provided a manifest of the flight, Black said. CNN has reached out to the CDC for comment.

Rensselaer County in upstate New York issued an advisory on Friday for the passengers on that flight. The county is working with the state health department and local health departments as the case develops.

In June, Delta announced 500 of its 90,000 nationwide employees tested positive for coronavirus. The airline said at the time they had added more space, clean surfaces and introduced safer service, including the requirement that all employees and customers wear face masks.

The airline also restored wine and beer options on July 2. Beverages were dropped abruptly from the service in March because the airline wanted to minimize interaction between flight attendants and passengers, but it has now worked on procedures to safely give the drinks to customers.

Delta is evaluating the return of spirits, soft drinks and a larger selection of snacks and meals.