The ACT-Accelerator brings together leaders of governments, global health organizations, businesses and philanthropies in a united response against COVID-19. The ACT-Accelerator is organized into four pillars of work: diagnostics, treatment, vaccines and health system strengthening. The Access to COVID-19 Tools (ACT) Accelerator, is a new, groundbreaking global collaboration to accelerate development, production, and equitable access to COVID-19 tests, treatments, and vaccines.