Health is contagious Unlike other factors that affect economic wellbeing(e.g.height or appearance)your health is determined by the health of those around you Ex:Hope your friends got their flu shots! Many economic externalities in health Both positive and negative ones Bhattacharya,Hyde and Tu-HealthEconomics Bhattacharya, Hyde and Tu – Health Economics Health is contagious  Unlike other factors that affect economic wellbeing (e.g. height or appearance) your health is determined by the health of those around you  Ex: Hope your friends got their flu shots!  Many economic externalities in health  Both positive and negative ones