The new coronavirus has been present in Washington state since at least January, when a Snohomish County man received the United States’ first known diagnosis.

Yet, public health officials and researchers still don’t know how many people have been infected because many people who have the virus show mild symptoms or, in some cases, no symptoms at all.

The state Department of Health (DOH) and UW Medicine are setting out to discover how prevalent COVID-19 is across the state by studying the blood of Washingtonians.

“We’re still trying to really understand, at a state level, where’s the virus really been? How many people have had it? And how does that vary between different parts of the state?” said Dr. Keith Jerome, head of the virology division in UW Medicine’s Department of Laboratory Medicine.

Serological surveys detect whether people have antibodies that develop in response to the body fighting an infection. Specimens for an antibody test are collected by drawing blood, as opposed to the nasal swabs used for COVID-19 diagnostic tests. Antibodies can develop five days to two weeks after symptoms stop.

The study is also intended to provide data to inform policymakers’ public health decisions as cases of COVID-19 continue to mount. The state saw its largest one-day total on July 16, with 1,267 new cases. As of Monday, 47,743 people in Washington had been infected, including 1,453 who have died.


UW Medicine and the Paul G. Allen Family Foundation, which granted $3.4 million for the survey, approached DOH and Gov. Jay Inslee’s office with the idea for the study, said DOH spokesperson Lisa Stromme Warren.

“Serology studies are important to improve surveillance and help us understand how many COVID-19 infections have occurred,” she said. “We are still learning about this virus — how it spreads and how it works. This may give us a better example of what community spread looks like in our area.”

The survey is expected to provide a clearer picture of whether certain populations — for example, racial and ethnic groups, or people working particular types of jobs — have been infected at higher rates, Jerome said.

“All these fundamental questions that we have are ultimately, we hope, going to be really useful to policymakers as we try and figure out what we’re going to do as we move through the summer and into fall, when typically these respiratory virus infections actually really start to ramp up again,” he said.

Because this is a new type of coronavirus, researchers are still learning about it and how it affects people: How effective are antibodies? How much immune protection might they provide, and for how long? How much of the population has been infected, and how many didn’t know it because they had mild symptoms or no symptoms at all?

This information gap makes serological studies an important tool to combat this virus, said Dr. Sridevi Devaraj, a professor at Baylor College of Medicine and medical director for clinical chemistry and point of care testing at Texas Children’s Hospital.


“These are the kinds of questions that, eventually, we’ll be able to answer only with large-scale surveys,” she said.

As valuable as large-scale serological surveys are to getting control of COVID-19’s spread, not many have been done, besides one in New York City, because they are expensive and require funding from the federal government or foundations, Devaraj said.

The Paul G. Allen Family Foundation had previously given to UW Medicine’s COVID-19 Emergency Response Fund but was looking for more opportunities to help, said Paul Keating, head of philanthropy at Vulcan, the company founded by the late Paul Allen and his sister, Jody Allen.

“The idea, generally, that we could help potentially put some additional data and scientific insight into the hands of planners and policymakers, and to inform the recovery, was really right along the lines of what we were looking for,” Keating said.

More on the COVID-19 pandemic

The survey, which will include 7,000 people, is modeled on an established strategy developed by the Centers for Disease Control and Prevention. Participants from all the state’s census tracts will be contacted by telephone, email or the U.S. Postal Service to be randomly invited to join. This system steers participation away from self-selection, Jerome said.


“By actually prospectively inviting people to participate, we’re more likely to get an unbiased, more accurate look,” he said.

Participants will first receive a diagnostic test, then three antibody tests during the next eight months. UW Medicine field teams will work with local, county and tribal authorities to do the testing and blood draws.

Jerome hopes to start testing by the end of the month, and the first set of results, which will create a baseline of how prevalent the disease is in the state, will be available sometime in the fall. The subsequent tests should reveal how effective antibodies are and how long they last.

The UW Medicine Virology Lab has been doing some antibody testing since mid-April, but it has been more narrow in focus.

The lab found about 3% of UW Medicine’s front-line health care workers carried antibodies, as did about 1% of some Fred Hutchinson Cancer Research Center employees who had been working from home in response to the pandemic.

Another serology survey conducted in the spring by Seattle Children’s hospital and Fred Hutch found about 1% of patients at Children’s carried antibodies.

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Correction: A previous version of this story misstated where funding came from for this research. It was from the Paul G. Allen Family Foundation, not from Vulcan.