Improving Estimates of Social Contact Patterns for Airborne Transmission of Respiratory Pathogens

Data on social contact patterns are widely used to parameterize age-mixing matrices in mathematical models of infectious diseases. Most studies focus on close contacts only (i.e., persons spoken with face-to-face). This focus may be appropriate for studies of droplet and short-range aerosol transmission but neglects casual or shared air contacts, who may be at risk from airborne transmission. Using data from 2 provinces in South Africa, we estimated age mixing patterns relevant for droplet transmission, non-saturating airborne transmission, and Mycobacterium tuberculosis transmission, an airborne infection where saturation of household contacts occurs. Estimated contact patterns by age did not vary greatly between the infection types, indicating that widespread use of close contact data may not be resulting in major inaccuracies. However, contact in persons >= 50 years of age was lower when we considered casual contacts, and therefore the contribution of older age groups to airborne transmission may be overestimated

Automated summary

Data on social contact patterns are widely used in mathematical models of infectious diseases. Most studies focus on close contacts, but casual contacts may also contribute to airborne transmission. Analyzing data from South Africa, this study found that age mixing patterns did not vary greatly between infection types, but older age groups had fewer casual contacts, suggesting an overestimation of their contribution to airborne transmission.