HOUSTON, Texas (KTRK) -- The findings of a recent antibody survey conducted by the city of Houston show four times more people had COVID-19 in September than what was previously known.
The results were shared during a briefing on Monday hosted by Mayor Sylvester Turner detailing the status of the city's antibody testing initiative.
Phase one of the program kicked off in September in which 420 homes were randomly selected and all members of each household were asked to answer questions and provide a blood sample.
Loren Hopkins, the Houston Health Department's chief environmental science officer, said participation exceeded the city's expectations, calling it "amazing." She adds 678 people provided blood samples.
"Our results show that an estimated 13.5% of Houstonians, which is approximately 250,000 people, had been infected with COVID-19 by September," explained Hopkins.
Data from the survey, which was an ongoing collaboration between the health department, Baylor College of Medicine and Rice University, showed an estimated 13.5% of Houstonians (approximately 250,000 people) previously had COVID-19 by Sep. 19.
The city says at that time, only 57,000 infections were identified by traditional viral testing.
The results also showed that a higher proportion of people with antibodies lived in high positivity rate areas (18%) of the city than those who lived in low positivity rate areas (10%).
Plus, the city says more women (17%) than men (10%) had antibodies, more Hispanics (18%) and Blacks (15%) had antibodies than non-Hispanic Whites (5%), and more people under 40 years of age (17%) than 40 and older (9%) had COVID-19 antibodies in their blood.
Survey teams will conduct phase two of the survey in January when people who participated in phase one will be re-tested to measure the number of antibodies remaining in their blood. Teams will also visit 420 new random Houston homes.
Only homes approached by the project's teams are eligible to participate, and participation is voluntary. The teams will be identifiable by their "Better. Together." shirts.
For more information about the antibody survey, visit the city of Houston's website.