Vaccination reduces the risk of becoming infected with and transmitting pathogens. The role of healthcare workers (HCWs) in controlling and limiting nosocomial infections has been stressed repeatedly. This has also been recognised at a political level, leading the European Council of Ministers in 2009 to encourage coverage of 75% seasonal influenza vaccine in HCWs. Although there are policies, recommendations and well-tolerated vaccines, still many HCWs refuse to get vaccinated. This article uses literature from psychology and behavioural economics to understand vaccination decisions and the specific situation of HCWs. HCWs are expected to be highly motivated to protect others. However, their individual vaccination decisions follow the same principles (of weighting individual risks) as everyone else’s vaccination decisions. This will lead to decisional conflict in a typical social dilemma situation, in which individual interests are at odds with collective interests. Failure to get vaccinated may be the result. If we understand the motivations and mechanisms of HCWs’ vaccine refusal, interventions and campaigns may be designed more effectively. Strategies to increase HCWs’ vaccine uptake should be directed towards correcting skewed risk perceptions and activating pro-social motivation in HCWs.