Talk for the International Symposium on Forecasting, 29 June 2021 and the Australian and New Zealand Statistics Conference, 8 July 2021. In March 2020, I joined a team responsible for providing probabilistic forecasts of COVID-19 cases to all Australian state & territory Chief Health Officers. We use case-level data of all Australian positive COVID cases, along with nationwide surveys and mobility data from Google, Facebook and Apple. Three separate models have been built: (1) a stochastic susceptible-exposed-infectious-recovered (SEEIIR) compartmental model; (2) a stochastic epidemic …