He is a Fellow of the Gerontological Society of America. He was a Visiting Professor at Nottingham Trent University, UK and at King´s College London, UK, and held an Honorary Chair at Manchester University, UK. He has published over 400 PubMed-listed papers, for an H-index of 105. Research interests are centred on how ageing affects immune function and influences the outcome of vaccination and immunotherapy, and how immunosenescence impacts human health and longevity.