Lavanya Visvabharathy, a T cell immunologist, has methodically applied her expertise to look at samples from patients at the Long Covid clinic at North Western University in Chicago, to try and establish the mechanism driving the disease.  Her personal experience of Long Covid's effects and the role of autoimmunity - she has both Long Covid and rheumatoid arthritis - combined with the wealth of data she has gathered, have led her to believe that Long Covid could be due to viral persistence.   In this fast-paced episode Visvabharathy talks us through her hypothesise, giving us a glimpse into her world of T cell dysfunction and autoimmunity, via the complexities of Long Covid NIH funding, and once again we discuss HIV and what we can learn from the way that virus is treated.