It is well-established that the gut microbiota plays a role in regulating the immune system, including modifying the response to viral infections. In fact, research indicates that the severity of COVID-19 is related in part to the composition of the gut microbiota. A microbiota configuration characterized by increased pathobionts and reduced immunoregulatory microbes was associated with poorer outcomes following infection. How can diet and nutrition support the microbiota-dependent immunoregulatory functions? What do we really know today, and what is under investigation? In this webinar, Prof. Liam O'Mahony of APC Microbiome Ireland provides an updated review of these relationships and what is ready for prime-time (or not!) in the patient and client nutrition counseling sphere.