Gerard is a Public Health Physician and infectious disease Epidemiologist from the Netherlands. He worked at the Public Health Service, Department of Infectious Disease Control Amsterdam from 2000 to 2018 in different roles, heading the department from 2013. He has been associated with the University of Amsterdam since 2009 for research and publication purposes. His research focuses on the epidemiology and control of infectious diseases and the evaluation of public health guidelines based on routinely collected, surveillance, and research data with a particular focus on equity. He holds a PhD in the evaluation of Public Health Programmes for Infectious Diseases.

Gerard relocated to New Zealand in 2019 and held positions with the University of Otago, the Institute of Environmental Science and Research Ltd (ESR) and the Ministry of Health in the national surveillance of infectious diseases including COVID-19. He collaborated with Dr Debbie Ryan in different projects, such as the response to the NZ measles outbreak 2019 and the response to COVID-19 for Pacific populations. Gerard joined Pacific Perspectives in June 2022.