Ever wonder why two people can have completely different experiences after catching COVID-19 at the same time? One person may get extremely sick, while the other may not have any symptoms at all.
Scientists say they’re closer to understanding one of the reasons why, thanks to a test developed by researchers at George Washington University.
The test could be a powerful tool to protect people during the pandemic. The researchers say they’ve developed a simple blood test that can quickly detect if someone has COVID-19 and predict how severely their immune system will react to the infection.
"We're using the person's own body to tell us that they think something is awry," said Dr. Tim McCaffrey, who’s leading the research project at GW. He says his team has developed a blood test that can predict who will develop severe symptoms from COVID and potentially end up in the ICU.
It all boils down to two specific RNA biomarkers found in a patient’s immune system.
"The pattern that we saw is in some of the people who get severe COVID, their neutrophils and their neutrophil reporters go markedly up, many, many fold up, but their T-cell markers go down very substantially," McCaffrey said. "The T-cells are a little bit like the brakes on your immune system, and when you lose those T-cells, the immune system is prone to spiraling out of control."
The findings, using blood samples collected from patients at George Washington University Hospital, were just published in the medical journal Public Library of Science (PLOS ONE).
Some of the patients were hospitalized because of COVID. Others were being treated for something else and later tested positive for the virus.
"So we could take advantage of that and compare those people with people that had full-blown COVID syndrome with the really, the full almost septic crash on these people where they have multi-organ system failure," McCaffrey said.
McCaffrey says the test is 95% accurate, regardless of the variant, because it measures a person’s unique immune response, and not the virus itself.
"This test is picking up people that we would argue clearly have infections that you can't detect by existing conventional diagnostics," he said.
"Eventually, you'll be able to use this test to determine whether you have a lung infection or whether you have appendicitis and abdominal infection; it really doesn't care what the infection is because it's reading your immune system," he said.
The test could give doctors another potential weapon, two years into the pandemic.
"The amount of teamwork and the amount of everybody rowing together, from the patients to the physicians to the scientists to get this done is something that I'm just unspeakably thankful about," McCaffrey said.
McCaffrey says they’re expanding the study to collect information from hundreds of patients around the United States. If the test remains effective, they’re planning to seek emergency use authorization from the FDA this fall.
This type of blood test is something that would be used at doctors' offices, hospitals and emergency rooms to give physicians an early warning about those patients they'll need to watch and which patients may need more aggressive treatments to fight COVID.