Game theory used to model the impact of earlier stockpiling and increased PPE storage during COVID-19 Kingston University London researchers have used a mathematical model known as a game theory to explore how the challenge of securing sufficient levels of vital personal protective equipment (PPE) for healthcare workers during the peak of the COVID-19 pandemic could have been mitigated. The need to protect frontline staff and key workers from coronavirus created an extraordinary demand for PPE across the globe in early 2020, resulting in inflated prices as countries competed against each other to secure huge orders of surgical masks, goggles, face shields, gowns, and gloves.