Routes of transmission of influenza A H1N1, SARS CoV, and norovirus in air cabin: Comparative analyses

Abstract

Identifying the exact transmission route(s) of infectious diseases in indoor environments is a crucial step in developing effective intervention strategies. In this study, we proposed a comparative analysis approach and built a model to simulate outbreaks of three different inflight infections in a similar cabin environment, i.e., influenza A H1N1, severe acute respiratory syndrome (SARS) coronavirus (CoV), and norovirus. The simulation results seemed to suggest that the close contact route was probably the most significant route (contributes 70%, 95% confidence interval (CI): 67%-72%) in the inflight transmission of influenza A H1N1 transmission; as a result, passengers within two rows of the index case had a significantly higher infection risk than others in the outbreak (relative risk (RR): 13.4, 95% CI: 1.5-121.2, P=0.019). For SARS CoV, the airborne, close contact and fomite routes contributed 21% (95% CI: 19%-23%), 29% (95% CI: 27%-31%), and 50% (95% CI: 48%-53%) respectively. For norovirus, the simulation results suggested that the fomite route played the dominant role (contributes 85%, 95% CI: 83%-87%) in most cases; as a result, passengers in aisle seats had a significantly higher infection risk than others (RR: 9.5, 95% CI: 1.2-77.4, P=0.022). This work highlighted a method for using observed outbreak data to analyze the roles of different infection transmission routes.