HOUSTON, Sept. 2 (Xinhua) -- An antibody testing survey will be conducted in U.S. Houston area that helps officials understand how many people were previously infected with COVID-19, Mayor Sylvester Turner announced on Wednesday.

During a press conference Wednesday afternoon, Turner said the city's health department is collaborating with the Centers for Disease Control and Prevention (CDC), Rice University and Baylor College of Medicine to perform the antibody testing survey.

The survey will help health officials identify people previously infected with the virus by the presence of antibodies, proteins the body's immune system makes to fight infections.

Local media quoted officials as saying that homes will be randomly selected across the Houston area for the survey. Those homes will be visited by team members of the health department and Houston Fire Department paramedics.

Household members will be asked to answer questions and provide a blood sample, officials said. The two-phased program is expected to begin on Sept. 8.

At Wednesday's briefing, Turner said that the city has not reached its 5 percent goal in positivity rate, asking people to continue to wear masks and be careful when more businesses begin to open.

On Wednesday, the Houston Health Department reported 176 new COVID-19 cases and 18 virus-related deaths.