Prof Lazarus is an expert on health systems and infectious diseases known for having developed the “Fourth 90” in HIV/AIDS and the micro-elimination approach in viral hepatitis C. He serves as head of the health systems team at the Barcelona Institute for Global Health (ISGlobal) an Associate Professor at the Faculty of Medicine, University of Barcelona and a Senior Scholar at CUNY SPH. He is Vice-Chairman of the board of the EASL International Liver Foundation, where he leads the work on NAFLD/NASH and the micro-elimination of hepatitis C, and he is co-chair of the HIV Outcomes Beyond Viral Suppression Coalition. He is the author of more than 250 publications including a co-author of the Lancet GastroHep Commission on Viral Hepatitis (2019), and lead author of the The Lancet HIV series HIV outcomes beyond viral suppression (2019) and COVID-SCORE, Nature Medicine and PLOS ONE (2020). During the COVID-19 pandemic, he joined The Lancet COVID-19 Commission public health taskforce and has been advising governments, NGOs and WHO, as well as frequently appearing in the media to address pressing issues about the pandemic.