Social Contact Tracing Research Articles

An empirical study on social contact tracing of COVID-19 from a classification perspective

An empirical study on social contact tracing of COVID-19 from a classification perspective

An explanation for the low proportion of tuberculosis that results from transmission between household and known social contacts

We currently have little idea where Mycobacterium tuberculosis (Mtb) transmission occurs in high incidence settings. Molecular studies suggest that only around 8–19% of transmission to adults occurs within-household, or between known social-contacts. This contrasts with findings from social-contact studies, which show that substantial proportions of contact time occur in households, workplaces and schools. A mathematical model of social-contact behaviour and Mtb transmission was developed, incorporating variation in susceptibility and infectiousness. Three types of contact were simulated: household, repeated (individuals outside household contacted repeatedly with daily-monthly frequency) and non-repeated. The model was parameterised using data from Cape Town, South Africa, on mean and variance in contact numbers and contact durations, by contact type, and fitted to an estimate of overdispersion in numbers of secondary cases (‘superspreading’) in Cape Town. Household, repeated, and non-repeated contacts contributed 36%, 13%, and 51% of contact time, and 13%, 8%, and 79% of disease, respectively. Results suggest contact saturation, exacerbated by long disease durations and superspreading, cause the high proportion of transmission between non-repeated contacts. Household and social-contact tracing is therefore unlikely to reach most tuberculosis cases. A better understanding of transmission locations, and methods to identify superspreaders, are urgently required to improve tuberculosis prevention strategies.

A double-risk monitoring and movement restriction policy for Ebola entry screening at airports in the United States

This paper provides an alternative policy for Ebola entry screening at airports in the United States. This alternative policy considers a social contact tracing (SCT) risk level, in addition to the current health risk level used by the CDC. The performances of both policies are compared based on the scenarios that occur and the expected cost associated with implementing such policies. Sensitivity analysis is performed to identify conditions under which one policy dominates the other policy. This analysis takes into account that the alternative policy requires additional data collection, which is balanced by a more cost-effective allocation of resources.