Social Risk Factors

Among risk factors for infectious diseases, social ones present a particular challenge due to the increasing importance of old and new infections on the one hand, and the complexity of social reality on the other. This is not a new phenomenon. Social risk factors for infectious diseases were a subject of much thought throughout, roughly, the early 19 century up to the First World War although rigorous epidemiologic methods were of course still rudimentary. Modern public health originated during that period even before the discovery of specific micro-organisms as infective agents (Rosen 1993). In addition to organizing public health services, its main preoccupation was hygiene, and hygiene then amounted, in modern epidemiologic terms, to the fight against the principal biological risk factor, which is the exposition to the known or suspected infective agent (see Chapter II.1). However, social factors like poverty, malnutrition, deficient water supply, crowded housings, and dangerous occupations played an equally important role. As it is well known, the interest in infectious diseases in general, and in their social risk factors in particular, waned in the sequel, especially after the Second World War, partly as a consequence of over-reliance on antibiotics in spite of early evidence for resistance phenomena (see Chapter I.4). Even hygienic standards declined in many places (see Chapter II.8). Then, in the last one or two decades, several phenomena contributed to a resurgence of activities around infectious diseases. More and more people, both in the medical professions and outside, became aware of the dangers of resistance of infective agents or their hosts to drugs or insecticides. Nosocomial infections became more frequent (see Chapter III.7). Finally, several new infectious diseases emerged (see Chapter I.3). Still, this renewed interest in infectious diseases has not yet lead to a large coherent body of studies on their social risk factors. There are several ways of looking at the influence of social risk factors on the distribution and spread of an infectious disease in a given population. What is indeed the meaning of a statement like “Poor people tend to suffer more than rich ones from