Short of a vaccine or proven treatment – the holy grail of the COVID-19 pandemic – the next best thing is a test showing immunity among people already exposed to the virus.
Experts at Oregon Health & Science University are working on multiple fronts to expand basic scientific understanding of the virus that causes COVID-19 and to develop a blood test that reliably identifies the presence of antibodies associated with it.
“Serologic testing is going to be important to know whether you have been exposed to SARS-CoV-2,” said Marcel Curlin, M.D., an associate professor of infectious diseases in the OHSU School of Medicine. “From there, we hope to learn if that means you are immune from reinfection or not. It’ll be relevant for everybody, and it’s going to be a cornerstone in understanding and controlling this pandemic.”
There are two kinds of tests.
The first involves looking for the SARS-Cov-2 virus itself, usually by swabbing mucus from the nose, then running the sample through a process called polymerase chain reaction to detect specific genetic material within the virus. The second involves analyzing blood samples to look for antibodies elicited during and following infection from the virus. In contrast to the first test, antibodies can be present in the blood for weeks, months or, potentially, even years after exposure to the virus.
Although there are now numerous antibody tests on the market, accuracy and precision varies and much remains unknown about whether or for how long immunity may last.
Blood samples for research
OHSU’s in-house COVID-19 testing lab is researching antibody testing by taking blood samples from health care workers who also undergo standard PCR tests for the virus.
The first step is validating that each test has detected the correct antibodies.
“There are many different coronaviruses, including ones that can cause the common cold,” said Donna Hansel, M.D., Ph.D., chair of pathology in the OHSU School of Medicine. “Some tests may react to these other viruses. We have been working to ensure our tests are as specific as possible.”
The clinical lab has enlisted a multidisciplinary team that includes Daniel Streblow, Ph.D., a professor in the OHSU Vaccine and Gene Therapy Institute, and Steve Kazmierczak, Ph.D., professor of pathology in the OHSU School of Medicine. The lab, made possible by a gift from Nike leaders and Phil and Penny Knight, is collaborating with other OHSU groups that study viral immunity.
The groups are working to answer other key questions:
- Can people become re-infected?
- Among people who have been infected, are there differences such as genetics or in the amount of virus in their system that determine the formation of antibodies in some people but not in others?
- How long do antibodies remain in the body following infection?
Improving the test’s accuracy is only the start; interpreting the results will be equally difficult.
“Understanding what the test means is something that will take longer and is a more complicated question,” Curlin said. “What those tests tell us will be different in a healthy 25-year-old than it will be in a 65-year-old renal transplant patient taking steroids who may be more susceptible to re-infection.”
Curlin is among dozens of OHSU scientists and clinicians focused on antibody testing. Using a $250,000 grant from the M.J. Murdock Charitable Trust, Curlin is working with Hansel and others to integrate laboratory research among specialists in infectious disease, occupational health and pathology.
Toward a reliable test
Ultimately, the goal is to develop a reliable test that can be useful in determining whether it’s safe for people who have been infected to return to public life.
Other researchers are looking to the long term.
Bill Messer, M.D., Ph.D., assistant professor of molecular microbiology and immunology and medicine (infectious diseases) in the OHSU School of Medicine, is leading a project enrolling patients who were treated for COVID-19 and recovered. Researchers will collect serum and whole blood samples for as long as five years after infection to ascertain the body’s response during the infection and how immunity evolves afterward.
He’s collaborating with Mark Slifka, Ph.D., an OHSU immunologist who has led groundbreaking work in other questions of immunity around diseases such as smallpox and tetanus.
Slifka said the pandemic has galvanized collaborations across the institution.
“Everyone wants to play a role in helping us get through this,” he said.
“This is a team effort,” she said. “We are all working closely together to coordinate our studies and share information with the goal of improving the long-term health of Oregonians.”