Can social network analysis assist in the prioritisation of contacts in a tuberculosis contact investigation?

OBJECTIVES: To evaluate the effectiveness of social network analysis (SNA) in prioritising contacts in a tuberculosis (TB) contact investigation.

METHOD: We reviewed and analysed patient and contact investigation data from a large outbreak that occurred in Tokyo, Japan, between 2010 and 2012. Relevant data were extracted to create a social matrix, which was then analysed using SNA software to visualise the network and calculate SNA metrics (degree and betweenness) for all patients and contacts. Statistical analyses were conducted to examine whether degree and betweenness centrality scores could prioritise contacts for in-depth investigation by calculating the odds of latent tuberculous infection (LTBI) being diagnosed among contacts with high scores compared to those with low scores.

RESULTS: The data on a total of 8 patients and 376 contacts, of whom 56 were diagnosed with LTBI, were analysed. Centrality scores did not show a statistically significant association with the risk of contacts being diagnosed with LTBI. However, contacts with high betweenness scores were more likely to be diagnosed with LTBI than contacts with lower scores (OR 2.88, 95%CI 1.31–5.83, P = 0.007).

CONCLUSION: Our results showed the potential of a betweenness score in prioritising contacts during TB contact investigation.