Evaluating Modes of Influenza Transmission
Condition: Influenza, Human
MeSH terms: Influenza, Human
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      The study will take place in a quarantine facility. Some volunteers (Donors) will be infected
      with the influenza virus via droplets into the nose. Other volunteers (Recipients) will then
      be exposed to them by occupying the same room (in the day time) and taking part in certain
      activities e.g. playing card games. Some of the Recipients will wear face shields and clean
      their hands regularly during the times they are with the Donors. The wearing of face shields
      together with good hand hygiene should reduce the spread of infection through large
      respiratory droplets and contact with contaminated surfaces but will not prevent infection
      that occurs through aerosols in the air. Use of symptom diaries and diagnostic tests for
      influenza will allow the presence of subsequent illness to be identified. Volunteers will be
      required to participate in the quarantine facility for up to approximately 13 days (typically
      9 for Donors and 13 days for Recipients), plus study screening clinics and followup.

      Additionally, during the study, environmental sampling will be performed looking for the
      presence of influenza virus. Air sampling and swabbing of surfaces and objects may provide
      information enabling us to better understand the routes of transmission.
    

Intervention name(s): Intervention Recipients Face Shield
Intervention type(s): Device
Intervention description(s): Face shield and repeat hand hygiene measures
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Human challenge model; Quarantine study; Influenza virus; Modes of transmission; Droplet spray; Droplet nuclei; Secondary attack rate; Face shield; Hand hygiene; Fomites; Environmental deposition; Environmental dispersion