Could being happier help us fight infectious disease? As the world embarks on a mass vaccination programme to protect populations from Covid-19, Crowdscience asks whether our mood has any impact on our immune systems. In other words, could being happier help us fight infectious diseases? Marnie Chesterton explores how our mental wellbeing can impact our physical health and hears that stress and anxiety make it harder for our natural defence systems to kick in – a field known as psychoneuroimmunology. Professor Kavita Vedhara from the University of Nottingham explains flu jabs are less successful in patients with chronic stress. So scientists are coming up with non-pharmacological ways to improve vaccine efficiency. We investigate the idea that watching a short feel-good video before receiving the inoculation could lead to increased production of antibodies to a virus. And talk to Professor Richard Davidson who says mindfulness reduces stress and makes vaccines more effective. [Image: Happy couple wearing masks. Credit: Getty Images]