Joséa Ratsirarson is a medical doctor and holds a Ph.D. in public health and epidemiology and a master's degree in public health. Joséa has worked for MCD Global Health for 20 years, serving as country representative and project director in Madagascar. His technical areas of expertise include maternal and child health, nutrition, family planning, water, sanitation and hygiene, communicable and non-communicable diseases, behavior change, health policy, and health system strengthening.

In 2016, Joséa served as the secretary general of the Ministry of Public Health of Madagascar for two years and held a joint appointment as a research professor at Mahajanga University in Madagascar teaching graduate-level public health students in epidemiology and public health.