Social determinants of infectious diseases: a public health priority.

Vulnerable groups are disproportionately affected by infectious diseases in every European Union (EU) Member State [1]. The level and distribution of wealth within a society plays a significant role in determining vulnerabilities to communicable diseases. A clear association between social welfare spending and mortality across EU countries has been reported [2]. The current measles outbreak in Bulgaria is a stark reminder of the urgency to act on social determinants of infectious diseases in Europe [3]. Since the onset of the outbreak in April 2009, over 23,429 measles cases and 24 deaths have been reported, 90% of which have been in the Roma ethnic community [4]. The majority of cases (>60%) were younger than 15 years and one third (30%) had not received the full course of measlesmumps-rubella (MMR) vaccination (Mira Kojouharova, personal communication June 2010). A number of factors converged to precipitate this epidemic: virus importation from Germany, socio-economic and health system reform, social marginalisation, crowded living conditions and a high degree of mobility among Roma communities (Mira Kojouharova, personal communication June 2010. Such socio-economic conditions could be fertile ground for outbreaks of other vaccine-preventable diseases (e.g. diphtheria, polio), if the agents were to be introduced into these or similar communities. Indeed, social determinants of infectious diseases are a significant public health issue throughout Europe. For instance, tuberculosis (TB) prevalence in EU Member States is inversely correlated with wealth and its distribution at an ecological level (Figure): with increasing socio-economic equality, TB rates drop [5].