Researchers in Utah are in the process of testing about 10,000 people for COVID-19 and antibodies against the virus that causes it.
“People have talked about how we see the tip of the iceberg with the formalized testing that we have,” said Dr. Stephen Alder, a professor of family and preventive medicine at the University of Utah and one of the project’s leaders. “We're trying to look at, ‘All right, how much of the iceberg is underwater?’ This is a good way to do that.”
The project is called Utah HERO, which stands for Help and Economic Recovery Outreach. Alder said the information is intended to help guide decisions that balance concerns about public health versus the economy.
“We're hoping that as we get that information here in the next few weeks, it's going to help guide us as to how we should be moving forward -- everything from getting businesses going to ‘What do we do for schools and universities, churches?’” he said. “There's so many groups that are really on hold until we understand this better.”
Alder said finding out whether certain communities have been hit harder than others could help shape a response.
“Do you need to, for instance, do something for the entire population? Or will targeted interventions that are more focused, more as we might say, ‘surgical’ -- will they work better, while retaining our ability to keep economies going?” he said.
The group is selecting a randomized sample of households in certain census blocks in four counties, including three of the most populous ones. Then, either in person or by mail, they’re asking everyone 12 years and older in those homes to participate in the study.
“We are approaching people and asking them to participate, rather than having them approach us,” said Alder.
They plan to test more people in areas that are known to have high rates of COVID-19, and adjust the results based on things like demographics and population density.
Ten thousand people is a lot compared to other serosurveys. Los Angeles, for example, tested just 1,000 people.
Daniel Larremore, a computational biologist with the University of Colorado, Boulder’s BioFrontiers Institute and computer science department, said sampling methods matter a lot, even more than the number of tests.
“If we don't get the sampling methods right, the risk is that the answer that we get from the study is wrong,” said Larremore, who has written about how to design COVID-19 surveys and isn’t involved in the Utah project. His lab also maintains a website for tracking such studies.
The Utah approach is different from that used in some other parts of the country. For example, researchers in California were heavily criticized for recruiting participants using a Facebook ad. The study concluded that many more people had been infected and recovered from COVID-19 than estimates showed, suggesting the virus was less deadly than previously thought. But other scientists said the group had essentially engineered those results, because people who thought they’d been sick would be more likely to enroll, motivated by the desire to get their antibody results.
Even with the Utah team’s approach for recruiting participants, the researchers will still have to keep an eye out for potential bias.
“The success of this study really hinges on high participation. If they have selected the areas in this nice, representative and random way, then if everybody in those areas participates, they'll get great and unbiased results that they won't have to worry about so much,” said Larremore. “But if only those people who think that they've been sick already participate and everybody else says, ‘I'm not interested,’ then the researchers will really have to consider what the value of the results are.”
Larremore reviewed details of the Utah group’s plan, and said it showed evidence “They have thought this through and have built in safeguards to check for representativeness, on top of their randomization.” Larremore said if done properly, such studies could help answer some questions that might be of use to other communities, too, like what role children might play in spreading the virus.
And regardless of the challenges of interpreting antibody surveys, he added, it’s notable that the researchers are using two tests, one used to identify current infections (using a method called PCR) and an antibody test to detect past infections.
“The results from their PCR tests are going to be valuable no matter what because anybody who tests positive, that is somebody who can get isolated, get the care they need and make sure that they protect the people around them,” he said.
Stephen Alder said the Utah HERO study should finish sampling in a few weeks, and that a second phase of testing would plan to follow up on the first by homing in on communities of interest, or tracking change in infection over time.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.
Do you have questions about COVID-19? How has this crisis affected you? Our reporters would love to hear from you. You can submit your question or share your story here.