Associate Professor Regan is a mathematical epidemiologist at the Kirby Institute, UNSW Sydney. He uses mathematical modelling to study infectious disease transmission dynamics and for evaluating interventions for their control and prevention. His research has focused on sexually transmitted infections and has included evaluations of a wide range of interventions for HIV, human papillomavirus, chlamydia, gonorrhoea, trichomoniasis, and hepatitis A. He has recently developed an interest in neglected tropical diseases and is currently collaborating with PRISM2 investigators on a model for evaluating mass drug administration for scabies in Fiji.