Evaluating Modes of Influenza Transmission

The ways in which influenza is transmitted between people are uncertain; for example, we do not know if large droplets or fine particles (aerosols) matter most; both are produced by coughing and sneezing. This means we cannot say what precautions work best in real life. Improving our understanding is vital to allow the development of guidelines and policies to help reduce the transmission of both pandemic and seasonal flu. The aim of this study is to explore how influenza is spread, specifically by looking at the importance of spread via small particles (aerosols/droplet nuclei) that are carried in respiratory sprays e.g. produced by coughing and sneezing. The primary objective of this study is: To estimate the contribution of aerosols/droplet nuclei to influenza transmission by determining the secondary attack rate (SAR) of influenza in Recipients randomised to a control arm (no intervention - allowing all modes of transmission) compared to Recipients randomised to an intervention arm (face shield and hand hygiene - allowing only transmission by aerosols/droplet nuclei) when both groups of Recipients are exposed to Donor volunteers infected with influenza via intranasal drops. The hypothesis is that: The SAR will be lower in Recipients exposed only to aerosols/droplet nuclei (intervention arm) compared to those exposed to all modes of transmission (the control arm): aerosols/droplet nuclei, droplet spray (larger respiratory droplets) and transmission through contact.