Updated 7/10, 5:45 pm to reflect funding from the City of Dallas and Tarrant County.
An ambitious new study will track the prevalence of COVID-19 in Dallas and Tarrant counties and answer pressing questions about how the disease is spreading through North Texas.
The study, being launched Monday by experts at UT Southwestern Medical Center and Texas Health Resources, will recruit 44,000 adults, ages 18 to 89, to answer survey questions and get tested for COVID-19 and antibodies to the novel coronavirus.
“There’s a lot of underrecognition of this disease,” said Dr. Amit Singal, the study’s principal investigator and a physician at UT Southwestern. “The first thing that we’re really trying to assess is exactly how many people have the infection and how many people have been exposed in the Dallas and Tarrant county areas.”
Budgeted at $10.7 million, the study is supported by Lyda Hill Philanthropies and other public and private partnerships. On Friday, Dallas County commissioners allocated $500,000 from the federal CARES Act toward the research. The City of Dallas and Tarrant County have also contributed funding.
The study, which will run through November 2021, will help answer such important questions as: How long might immunity last? What share of North Texans with COVID-19 are asymptomatic? How does prevalence change with age, household size, profession, socioeconomic status, children’s participation in day care and sports, and personal behavior? And what accounts for the disproportionate toll COVID-19 has taken on Latino and Black communities?
Until now, scientists have been able to offer only partial answers to these questions. A lack of widespread testing has resulted in data that is skewed toward those with the most severe symptoms and the best access to health care. Demographic information is often missing.
Volunteers for the study will be selected by invitation only, based on census tracts, to help ensure representation from a wide range of socioeconomic and ethnic groups.
And UT Southwestern and Texas Health Resources will set up a dozen new testing sites to make visits convenient for participants.
“This type of study is very useful for getting a handle on true patterns of infection that aren’t biased by things that we know can really influence data,” said Marm Kilpatrick, an infectious disease expert at the University of California Santa Cruz, who is not involved in the new research.
Beginning Monday, the first of 30,000 notices will be mailed to people in the D-FW area inviting them to participate in the study. Participants will be asked to fill out a survey online or agree to take one by phone, either in English or Spanish.
An additional 14,000 volunteers will be recruited through partnerships with essential businesses including supermarkets, big-box stores, airlines and restaurants.
All 44,000 volunteers will receive two tests: a nasal swab to check for the presence of the virus that causes COVID-19, and a blood test that checks for the presence of antibodies to the virus. The presence of antibodies means the volunteer was probably exposed to the virus and recovered.
Both tests used in the study are from Abbott Labs and have an accuracy rate of more than 99%, according to UT Southwestern. Singal said colleagues involved in the study had validated the antibody test using samples from patients known to have recovered from COVID-19, as well as those who had never had the virus.
All volunteers who receive positive results on either test, plus a randomly selected subset of those who test negative, will be retested after six and 12 months.
The ability to follow individuals over time will help researchers assess how long immunity might last, whether people can be reinfected with the new coronavirus, and which demographic groups have the most exposure to the virus, said Jasmin Tiro, a public health expert at UT Southwestern and co-investigator of the study.
Studies conducted in other U.S. cities have found a wide range in the share of residents who have been exposed to COVID-19. Rates varied from 4.7% in Los Angeles to 23% in New York City, based on antibody tests. Singal estimates that, before the current surge, around 5% of people in Dallas and Tarrant counties had been exposed.
Even now, the Dallas-Fort Worth area probably remains far from achieving herd immunity — a stage at which enough people have developed immunity to a virus to stop its spread.
Kilpatrick says 40% to 60% of residents need to be immune in order to limit new infections, a threshold reached most safely with vaccination.
The UT Southwestern-Texas Health Resources study’s large sample size will allow researchers to examine patterns of COVID transmission among different population groups. The survey will ask about ethnicity, household size, insurance coverage, ability to physically distance from others at work, children’s activities and personal physical-distancing and mask-wearing behavior, among other things.
Researchers expect to complete enrollment by November and to finish the study by the end of next year. They said they would release results throughout the course of the study.
The main obstacle, they said, would be getting people to open their mail and opt in to the research, not just because people are busy and fearful but also because of growing distrust of scientific expertise.
“This is the first post-truth epidemic,” UT Southwestern’s Tiro said. “That means we have to be especially thoughtful and careful in our communications.”
Researchers are working with a 30-member community advisory board made up of representatives from religious faiths, businesses, nonprofits and other groups in Tarrant and Dallas counties. The board will offer feedback and help researchers communicate their findings to the public.
Researchers are also launching a bilingual public information campaign through social media and distributing informational flyers through businesses such as grocery stores.
Those who fail to respond to the mailed invitations will be contacted by researchers and, if they decline to participate, will be replaced with other households from the same census tracts.
Singal and his colleagues are eager to get started. “These are data, particularly now that we have a surge in North Texas, that we want as soon as possible,” he said. “These are data that we wish we had yesterday.”
Staff writer Nic Garcia contributed to this story