Incorporating social environment data in infectious disease research

Research on pathogens such as tuberculosis, human immunodeficiency virus (HIV), and cholera have long considered the importance of the environment-particularly the social environment-for understanding population patterns of infectious diseases and their inequities.However, a growing body of research has begun extending such approaches more broadly in infectious disease research.At a fundamental level, the social environment can impact infectious disease risk in two ways: by affecting a person's frequency or duration of exposure to pathogens, or by affecting their susceptibility to infection. 1 Social stress theory has emerged as a key mechanism through which a person's susceptibility to infectious diseases might be shaped by their social environment. 2,3The work by Marko Elovainio and colleagues 4 published in this issue of The Lancet Public Health provides an important addition to this line of inquiry-making a strong case that the experience of loneliness is a robust predictor of susceptibility to hospital-treated infectious diseases.