Epstein–Barr virus
Barr, along with her research supervisor Epstein, discovered the Epstein–Barr virus (EBV) during her PhD studies in 1964 at Middlesex Hospital. Prior to determining specifics about EBV, Epstein, Barr, and Bert Achong published their preliminary research in The Lancet. Barr was instrumental in the discovery of the Epstein-Barr virus, also called human herpesvirus 4, by preparing the samples used for experimentation.