As Teton County begins looking toward a phased reopening, two groups are pursuing separate strategies to test people for COVID-19 antibodies despite a dearth of knowledge about the ability of those antibodies to protect against reinfection.
St. John’s Health wants to see what level of exposure frontline health care workers and first-responders have had to the virus. Test Teton Now, a new working group, has a more expansive goal of testing between 8,000 and 9,000 people.
Test Teton Now expects to start offering tests at private health care clinics for $75 a pop as soon as Thursday. First responders and those who can’t afford the fee will be tested for free.
Jennifer Ford, the group’s communication manager, said in an email that the group views antibody testing as “one tool in a rapidly changing and emerging field of research into this terrible virus.” Test Teton Now refused several requests for phone interviews.
“We believe that COVID-19 antibody testing is an important tool in understanding the prevalence and spread of COVID-19 in our community and our world,” Ford wrote.
Health officials, however, question whether the time is right and the technology is ready.
The allure has amped up in recent weeks. Studies across the country have used such testing to investigate what percentage of their local population has developed antibodies to COVID-19, the disease caused by the new coronavirus, SARS-CoV-2.
A study in New York showed that up to 14% of that state’s population could have been infected at one point. California studies hinted at rates of between 4% and 5% in Santa Clara and Los Angeles counties, though experts have questioned the results.
In Teton County health officials question whether that sort of data is the right information to lean on when thinking about reopening Jackson Hole’s economy.
“Antibody testing is not going to change anything from a public health perspective in terms of opening back up,” Director of Health Jodie Pond said.
Antibody testing tells people who test positive that their body has COVID-19 antibodies, blood proteins the body develops to fight infections after coming into contact with harmful intruders like viruses and bacteria.
It does not tell people whether they are actively infected with the virus. RT-PCR testing does, which is part of the reason health officials are working to bring more of that testing online.
Antibody testing also does not tell people whether they are symptomatic and does not provide information about immunity. Science on the subject of the body’s immune response to COVID-19 is in its early stages, and results are mixed about how long immunity might last and how strong that immune response might be.
Underlying all of that is worry about false positives, which would incorrectly tell someone they have developed antibodies to fight the virus when they have not. That could lead them to errantly loosen their adherence to social distancing guidelines based on a faulty premise, St. John’s CEO Paul Beaupre said during Friday’s COVID-19 community update.
“My one plea is if you decide to get your antibody checked right now, please do not make any individual decisions about how you’re going to behave,” he said. “Please get good advice about what the results mean before you change your behavior.”
Ford said Test Teton Now has “put protocols in place at participating clinics so that patients understand what their results mean.”
The science behind testing
Antibody tests can look for several types of the blood proteins. Antibodies are specific to the illness itself, or disease specific. An accurate test can determine whether someone has had COVID-19, rather than another viral infection.
The two most prevalent antibodies in COVID-19 testing are IgM and IgG. IgM is created when the body contracts a new virus, while IgG can take a while to build up in the bloodstream.
Once IgG is created, it replaces IgM as the predominant antibody.
“IgG is the antibody that typically is part of the antibody pool for the long term,” said Vicente Planelles, a professor of microbiology and immunology at the University of Utah. “That is how you measure immunological memory.”
How long IgG stays in the system and how long it is effective in preventing reinfection varies by disease. Chickenpox antibodies are lifelong. Those developed against influenza may last only a year or two.
Scant evidence exists on how long antibodies for COVID-19 may last and what level of immunity they confer, so antibody tests may not give individuals a lot of information.
One study on macaques in China found the primates couldn’t be infected a second time, and humans’ immune reactions are often similar to other primate species. The study was small, not conducted in humans and isn’t enough to be definitive proof of immunity.
Public health officials remain wary, but Planelles said with evidence from other coronaviruses like SARS or the common cold, drawing inferences about immunity may be appropriate.
“It is not a stretch to assume that somebody who has antibodies is immune,” Planelles said. “There are two flavors to immunity: You can be immune to where you can have re-exposure and you don’t get infected, but you could also be reinfected and it would be much less severe.”
Worry over false positives
Government officials and health care leaders around the world have pointed to antibody tests as a tool to reopen society. The thinking is that if large numbers of people were already exposed to the virus and could be considered safe from reinfection, the economy could reopen in part.
However, antibody tests don’t appear to be a panacea. Worries about false positives could undermine the results from even the most sensitive tests.
Planelles said those high sensitivity tests may only be around 95% accurate, which could mean that 5% of people who are tested with them could be told they have antibodies when they don’t.
But even if a test were shown to be 100% accurate, the results likely wouldn’t be enough to sway Teton County’s public health officials.
To do that, testing would likely have to show that the disease had infected far more people in the county than previously thought, bringing local COVID-19 prevalence close to the 70% or so required for herd immunity. That’s a population-wide condition where enough people have been exposed to a disease to prevent widespread infection.
“I don’t expect that we’re going to have a prevalence higher than 2%,” Pond said. “When we’re talking about herd immunity at 70%, that does not change anything I do to open up more quickly. It might even lead me to say we should go slower.”
Bringing testing online
Discussion about antibody testing in Teton County began in late March, around the time when Covaxx, a subsidiary of an international biotech firm, United Biomedical, offered to test all of San Miguel County, Colorado, for COVID-19 antibodies.
That program, which would have seen people tested twice, was delayed. The company said COVID-19-related problems at its New York lab, which was processing the tests, had slowed it down. The second round of testing has been postponed indefinitely.
People in Teton County have pushed to bring a similar program here. Ultimately, St. John’s Health purchased 1,000 tests from Covaxx — enough to test 500 frontline workers if the hospital stuck to the same two test schedules proposed in San Miguel County.
But when St. John’s CEO Beaupre read about the delays in Colorado, he pumped the brakes. Part of the reason was to assemble a panel and evaluate the range of testing available, with the goal of proceeding with a test approved by the U.S. Food and Drug Administration.
The hospital’s shipment of tests never made it to Teton County. A wire transfer from the hospital that would have paid for the tests, donated by Tom Katis, was never sent.
“I’m actually delighted that the wire didn’t go through because now I don’t have to ask for the money back,” Beaupre said after cancelling the program.
He announced Friday that the hospital would instead move forward with a test made by Abbott Laboratories. That was a day after Test Teton Now said it was moving forward with Covaxx’s test.
The group, Ford said, is “test-kit agnostic.”
Covaxx’s parent company’s history of working in infectious disease and the limited availability of antibody tests were both part of the reason Test Teton Now chose its test.
“Even in the field of antibody testing, availability is limited,” Ford wrote. “Covaxx had the ability to provide tests and transparency around their process that we needed to move forward.”
The hospital’s panel chose the Abbot test because it is cost effective, runs on machines St. John’s already operates, and is FDA approved. Covaxx’s test has not received FDA approval.
Both Abbott and Covaxx claim their tests have near 100% sensitivity, the ability to identify positive cases correctly, and, specificity, the ability to identify negative cases correctly. But they don’t actively share the data to back up those claims, so local groups are looking to validate their tests themselves.
“Our testing and validation process is ongoing,” Ford wrote.
With an initial supply of 300 tests, the group is working to validate the sensitivity and specificity Covaxx reports through “blind control testing of the blood samples from patients who have previously tested positive for the COVID-19 virus.”
The hospital is likewise planning to run a test with known positives and known negatives to determine accuracy rates. Regardless of what sensitivity rate a company claims, Beaupre said, “your lab’s machine may be off, so you really have to understand your own machines.”
Understanding the sensitivity rate of a test is crucial because it is tied to the rate of false positives. Even a test that has a proven 95% sensitivity rate can have large levels of false positives when the prevalence of a disease is low.
“That’s dangerous,” Pond said, “because somebody might take that information and say, ‘I have an immunity certificate,’ and that doesn’t mean that at all.”
The hospital and Test Teton Now are also looking to work with others as they begin testing.
Test Teton Now is “sending samples and our test results to labs around the country to help with the analysis of the tests and our protocols,” Ford wrote. “These are major research institutions and as we finalize our collaboration agreements we will share more about this process.”
Beaupre is likewise looking for an academic partner, though for different reasons.
Gathering data in real-time during the pandemic is critical for understanding it, so Beaupre said he is “shopping” the data to universities to aid researchers.
“Going with a university helps the United States and world get a better understanding of what this disease is really doing,” he said.
Using the data here — or not
The hospital is testing first-responders and frontline hospital workers, Beaupre said, because they likely had the most exposure to the virus. If they have low rates of incidence, that could be a sign it may be too early for widespread testing of the general public, he said.
Test Teton Now is offering testing to the community to provide another “data point.”
“Good decision-making is based on data,” Ford wrote. “Test Teton Now aims to provide more data points on the spread and prevalence of COVID-19 in our community. We are simply providing another data set, and we understand this is an evolving area of research.”
Test Teton Now and the valley’s medical establishment agree that more testing is needed to open Teton County. But health officials say testing for active infection is more important.
With at least 17 people on staff for tracing efforts, getting equipment for active disease testing remains an obstacle. In recent days, testing guidelines have relaxed, opening testing up to anybody who is symptomatic. The health department and hospital have also begun bringing a rapid, active disease testing program online.
In Pond’s mind those programs are more important than testing for antibodies because they can aid in contact tracing, the process of finding and testing people who have come into contact with an infected person, to slow the spread of the disease.
With the virus active in the community, finding and isolating those people is one of the most effective ways to stop its spread.
“It doesn’t seem like antibody testing is where we should put our money,” Pond said. “I’d like to see somebody with $1 million for antibody testing set up mobile clinics and test for PCR instead.”
To date, donors have contributed $335,000 to Test Teton Now, Ford said. That’s intended “to help offset the cost of blood draws at participating clinics and testing at the laboratory.”
Ford also said the working group is happy to work with county officials when appropriate.
“We are happy to share data as allowed by federal, state and local law with health officials,” she wrote. “We understand they are incredibly busy and have many competing interests to balance. We are here if and when they would like to collaborate.”
With questions about antibody testing’s community relevance, and what it can and can’t say about individuals’ viral status, Pond stressed again that the public should not use antibody tests as immunity passports to relax their behaviors.
“There’s no science about what that means for an individual at this time,” Pond said. “It’s not going to tell you’re good to go and take your spring trip to Italy.”