Incentivising wealthy nations to participate in the COVID-19 Vaccine Global Access Facility (COVAX): a game theory perspective

### Summary box Progress in developing COVID-19 vaccines has been rapid: the first clinical trial of a vaccine candidate began in Seattle, USA on 16 March 2020—just 63 days after China shared the genetic sequence of SARS-CoV-2, the virus that causes COVID-19. As of 12 November 2020, there were 48 candidate vaccines in clinical trials.1 Given standard attrition rates, we can expect at least a handful of COVID-19 vaccines to eventually be launched. However, developing a safe, effective vaccine alone will not be enough to end the pandemic. The vaccine must also be delivered globally at a price affordable to all governments and allocated in a way that maximises immediate and long-term public health impact and simultaneously achieves equity. In previous pandemics, these goals were not achieved. For example, in the 2009 influenza A (H1N1) pandemic, rich countries monopolised the vaccine supply; low-income countries (LICs) and middle-income countries (MICs) received …