NEW ORLEANS — A study of New Orleans area residents infected with the coronavirus indicates 75 percent had no symptoms.

The study released Thursday by researchers at New Orleans-based Ochsner Health was done in May. It looked at testing of residents in New Orleans and neighboring Jefferson Parish. The study indicated a death rate among those infected of 1.63%, much more deadly than the flu.

Researchers selected 2,640 people, representing varied demographic groups from Orleans and Jefferson, from among 25,000 volunteers. They received nasal swab tests for the virus and blood tests for antibodies.

Another finding in the study: Infection rates were higher among Black residents (10.3%) than white residents (5.9%). The death rates of 1.72% and 1.58%, respectively, were not considered statistically significant.

Ochsner’s chief medical officer, Dr. Robert Hart, says the study demonstrated the need for masking and social distancing as the virus shows signs of resurgence in Louisiana and around the country.

“We need to assume that we could all potientially be carriers,” Hart said.