Who mixes with whom? A method to determine the contact patterns of adults that may lead to the spread of airborne infections

TLDR

Mixing patterns are key to airborne disease spread, yet no human studies have directly quantified them. The study aims to identify and quantify adult mixing patterns and proposes questionnaire modifications to capture social network structure and contact intensity for infection transmission analysis. A sample of 92 adults reported contacts over a single day, 65 completed the questionnaire, and the data were analyzed with multilevel modelling. The study quantified adult contact patterns, revealing age‑dependent assortativity and varying contact rates across social settings, highlighting epidemiological significance for outbreak potential.

Abstract

Although mixing patterns are thought to be important determinants of the spread of airborne infectious diseases, to our knowledge, there have been no attempts to directly quantify them for humans. We report on a preliminary study to identify such mixing patterns. A sample of 92 adults were asked to detail the individuals with whom they had conversed over the period of one, randomly assigned, day. Sixty–five (71 per cent) completed the questionnaire, providing their age, the age of their contacts and the social context in which the contacts took place. The data were analysed using multilevel modelling. The study identified, and allowed the quantification of, contact patterns within this sample that may be of epidemiological significance. For example, the degree of assortativeness of mixing with respect to age was dependent not only on the age of participants but the number of contacts made. Estimates of the relative magnitude of contact rates between different social settings were made, with implications for outbreak potential. Simple questionnaire modifications are suggested which would yield information on the structure and dynamics of social networks and the intensity of contacts. Surveys of this nature may enable the quantification of who acquires infection from whom and from where.