The bacteria in your gut help regulate your immune system. So, can priming them with an over-the-counter probiotic protect against COVID-19?

A Duke Cancer Institute physician-scientist and a critical care specialist are exploring that question, via a clinical study being conducted entirely remotely and made possible by philanthropy.

Tony Sung, MD, a stem cell transplant physician and an associate director of the Duke Microbiome Center, has long been interested in the microbiome (the collection of all the bacteria and other microorganisms that live in the human body) because it can influence complications in patients after stem cell transplant, including relapse, survival, and infection.

Paul Wischmeyer, MD, professor of anesthesiology and surgery, specializes in enhancing preparation and recovery from surgery and critical care.

Both were familiar with studies showing that taking an over-the-counter probiotic can help reduce the risk of respiratory infections and even more severe infections such as sepsis. Wischmeyer himself had done studies showing that, in a mouse model that mimics pneumonia, giving the mouse a probiotic (Lactobacillus rhamnosus GG) protected against infection and improved survival.

The two scientists knew each other but had never collaborated. Then the pandemic cemented a partnership. “In the setting of COVID-19, we have a call to respond,” Sung says.

Sung and Wischmeyer launched a trial that tests whether taking a common, over-the-counter probiotic (the same one that Wischmeyer used in his study with mice) can help prevent development of symptoms or reduce severity of symptoms in people who live with someone who has tested posted for COVID-19.

Participants receive the probiotics and submit nasal swabs and fecal samples by mail, so anyone in the United States can participate without having to leave home.

“There are lots of data supporting this as a viable hypothesis, but it’s a hypothesis that needs to be tested, which is what makes this clinical trial so important,” Sung says. While he can’t make recommendations to the general public about taking probiotics until the trial is completed, he acknowledges that since the pandemic began, he has been taking one himself, as does his two-year-old daughter, who spent time in the ICU with a common cold as a baby.

“Probiotics are cheap, safe for healthy people, and readily available. If probiotics could help attenuate symptoms and prevent hospitalizations, it would be a huge win,” Sung says.

An established investigator funded by the National Institutes of Health (NIH), Sung had never funded his research with philanthropy before. But the urgency of the pandemic promoted him to reach out to his former classmate from Stanford University, Joe Lonsdale, who thought the study was important enough to make a $40,000 gift through his company, Lonsdale Enterprises.

"Tony embodies a lot of great traits, including brilliance, integrity, and hard work,” Lonsdale says. “The microbiome is an important area of research, and it's an honor to be able to support a researcher like Tony with resources to work on ways to ameliorate the terrible impact of COVID-19."

The trial would not be open now without that gift and other donor funds, Sung says.

“There was a grant application we sent to the NIH around the same time that we started this study. We still have yet to hear back whether that is funded or not,” he says. “Philanthropy allows us to move much more quickly and react to emergencies like the COVID-19 pandemic.”

The study is also funded by the Duke Microbiome Center, as well as small donations from several other individuals. Manufacturer DSM is providing the probiotic and a placebo for use in the trial.

This article appears in the Winter 2021 issue of Breakthroughs magazine. Breakthroughs is produced twice yearly by Duke Cancer Institute Office of Development.