University of Minnesota, Mayo Clinic ready COVID-19 antibody tests in Minnesota

Researchers nationwide are racing to develop antibody tests, which under current emergency pandemic conditions would not need the usual level of review and approval from the U.S. Food and Drug Administration. Exactly how much verification of tests is needed is unclear, but Jenkins said he wants to at least get successful results for 10 positive and 10 negative specimens before even considering the test for public use. He expected to have that many results in the next couple of weeks.

“It’s going to take a lot more samples … to validate the test,” he said, “but we have a pipeline to do it and the results from these early tests were so clean that I’m pretty hopeful.”

Mayo has used more than 300 samples to evaluate the accuracy of three different assay tests, and has found one ELISA-based test to be most accurate, said Elitza Theel, director of Mayo’s Infectious Diseases Serology lab.

Theel said it will be critical for doctors to understand that the current molecular tests are still the best for diagnosing symptomatic patients — and that new antibody tests won’t solve any national shortage of those. However, from a disease-detective standpoint, health officials will be able to use antibody tests to determine when a community has achieved “herd immunity” — which means that enough people have already been infected that the risk of new infections starts to diminish.

COVID-19 is a respiratory illness caused by the novel coronavirus that emerged earlier this winter in Wuhan, China, and spread globally. Initial reports indicated a death rate of anywhere from 1% to 3.4%, but an abundance of antibody testing would provide a more accurate picture because it would allow for testing of both sick and healthy people to find out how many of them have been infected.

“When you have an actual true denominator, you’re able to determine the true case fatality rate,” Theel said.

Local studies on antibody testing didn’t occur until recently, because researchers needed substantial samples from COVID-19 patients to do it, and because there was a more immediate need to develop diagnostic molecular tests for the illness.

Quality problems with a molecular test created by the U.S. Centers for Disease Control and Prevention initially delayed states such as Minnesota from using it. Then, supply shortages prevented its broader use, even as the coronavirus was spreading nationwide.

Mayo and other private labs created their own versions of the molecular tests, and now have conducted more such tests than the state’s public health lab, which has prioritized its limited supplies for hospitalized patients, long-term care facility residents and health care workers.

Jenkins said he first started looking at antibody tests when news of testing supply shortages emerged. Knowing that antibody testing could provide invaluable public information, he said he wanted to create a pipeline for these tests on which Minnesota could rely.

Jenkins acquired a COVID-19 protein that is critical to the test from Fang Li, the U researcher whose recent Nature journal article explored the genetic origins of this coronavirus and its evolved mechanism for infecting cells.

Other coronaviruses cause the common cold and also were responsible for global SARS and MERS outbreaks. Jenkins said he will be checking to make sure the newly developed test identifies only cases of COVID-19 infections.

Whether antibody testing could be used as an all-clear system for people is based on a key assumption: that people develop at least short-term immunity to the coronavirus.

One small study in China found no reinfections in monkeys when they were exposed to the virus a second time. Researchers also believe that people develop immunity to other coronaviruses that lasts months or maybe years. Antibodies were found in patients six years after the 2002-2003 SARS epidemic.