Rigorous coronavirus antibody testing coming to Orange County
What’s the local footprint of COVID-19? That could be answered by test involving UC Irvine and county health officials.
May 14, 2020
Originally published in the Orange County Register
The County of Orange has tapped UC Irvine to answer the burning question: How many people here have been infected with COVID-19?
In perhaps the most comprehensive effort to date in California, researchers will examine the blood of 5,000 people for antibodies to the virus to better understand how widespread the disease has become in Orange County.
Starting this month, researchers will examine a representative sample of the county’s population, set up eight to 10 drive-through sites, administer pin-prick tests to collect blood, then send the samples to UCI for analysis.
Similar efforts in Los Angeles and Santa Clara counties found that the number of infections was vastly larger than the number of confirmed cases. Officials here expect to find the same.
The UCI study, though, is designed to be more comprehensive and rigorous than its predecessors’. The local test will include many more people than were tested in L.A. or Santa Clara. Researchers also will go to the homes of subjects who can’t make it to drive-through sites, with a special eye toward reaching under-served communities. That will help them make better estimates on disease prevalence by age and race/ethnicity.
They’ll also follow some subjects over time, to see how their immune responses change.
“(O)ur project departs significantly from earlier work,” says the study prospectus.
Bernadette Boden-Albala, director and founding dean for UCI’s Program in Public Health, is directing the effort, along with Tim-Allen Bruckner, associate professor. The study will cost $1.5 million, the proposal says, and is the largest of three surveillance studies in the works at UCI.
The studies in L.A. and Santa Clara have been dinged for either having small samples (about 860 people in L.A., a county of 10 million), or for having samples that don’t reflect the county as a whole (some 3,300 Santa Clara participants were recruited on social media). Orange County’s effort takes those lessons to heart.
“I have all positive things to say about LA and Santa Clara — they’re doing what they needed to do to try to get at the truth,” said Boden-Albala. “We learned from them. We’re really going to be able to do this right in O.C.”
On Thursday, May 14, Orange County reported the largest number of new COVID-19 cases to date — 229. Overall, the county has logged 3,968 cases and 80 deaths.
Could be you
Blood serology tests aren’t designed to diagnose active infections in sick people, but rather to find phantom cases — folks who’ve contracted the virus in the past but didn’t get very sick, or who didn’t show any symptoms at all.
These folks didn’t get the traditional, molecular diagnostic test — which collects gunk from the nose and throat and then searches for the virus’s genetic material — so they’re not counted in the county’s tally of confirmed COVID-19 cases.
Serology tests can find past infections by detecting antibodies to the virus in the blood. Antibodies are produced when the body mounts an immune response to fight an infection. Having a better idea how wide infection truly is will be key to guiding officials on next steps, including when and how to reopen the economy.
To that end, thousands of phones will ring and inboxes will ding in coming days.
The LRW Group — which recruited a solid sample for L.A.’s study and has email, mobile and land-line information for more than 800,000 adults in Orange County — will be charged with pulling together the sample of 5,000 people that’s representative of Orange County at large.
“We want to be mindful that we’re covering really everybody, to be able to make statements with confidence,” Boden-Albala said.
Researchers are finalizing which finger-prick test to use. They hope to start testing within the next several weeks, analyze results in June, and publish in July.
Data from the longitudinal arm of the study will be analyzed next, with an eye to publication in the fall. It will involve a subset of about 200 participants who tested positive for COVID-19 or for antibodies, who’ll have blood drawn every two weeks over a four-month period.
“The blood samples will be used to independently validate the findings from the tests being used in the larger study and to measure the duration and persistence of immunological responses … over time,” the study prospectus says. “We will also document any reinfections and subsequent symptomology among this cohort.”
That piece may shed a great deal of light.
“There are so many things we want to look at,” Boden-Albala said. “Does the antibody response remain? It’s not just yes or no — how does that play out over time? If people who’ve been exposed once are exposed again, what does that do? That’s particularly pertinent for health care workers and first responders.”
What does it mean?
This surveillance study, which will be sent to the County Board of Supervisors, will have three clear and immediate implications. They are: to inform policies regarding where, for whom and for how long to continue restrictive public health measures; to inform identification and targeting of those at the greatest risk for the disease; and to understand the persistence and duration of immunological responses, which “may hold relevance for reaching herd immunity and/or vaccine development.”
The surveillance studies in L.A., Santa Clara and New York City also aimed to do much the same. What they found varied widely.
In Santa Clara, about 2.8% of folks had antibodies to the virus. In Los Angeles, it was about 4.1 percent. And in New York City — at the time the hardest-hit pocket of America — it was 21.6%.
Taken together, that indicates the fatality rate of COVID- 19 is 28- to 80-fold less than currently estimated, the prospectus says, and that the prevalence of COVID-19 antibodies varies substantially from place to place.
Even if numbers from those three studies aren’t perfect, two things are clear: Many more people have been infected than the diagnostic case numbers indicate; and the overwhelming majority of folks haven’t yet been exposed to the virus.
That means “we’re in this for a while,” said Boden-Albala. “It’ll ebb and flow. There’ll be peaks when the numbers go up, and times when the spread is really very slow. It’s the new norm. I don’t think any of us wants that, but that’s the deal.”