Theme 2: Approaches to evaluate environmental transmission mechanisms and controls

What we are doing

This theme focuses on methodologies to understand and quantify transmission through different routes. Alongside Theme 4 and Theme 5 , Theme 2 will initiate a programme to build national capability in this interdisciplinary space at the interfaces of microbiology, mathematical modelling, building science and human behaviour.

Why we are doing it

We know that COVID-19 spreads through respiratory droplets and aerosols, and via surfaces. However, we understand very little about the micro-scale dynamics of transmission in the environment:

  • There is good evidence that high transmission risk is associated with close proximity for a prolonged period in crowded/poorly ventilated spaces, but we don’t know how much of this transmission is through droplets at close range, aerosols or contact with surfaces.
  • Super spreading events appear to play a major part in transmission, but we don’t know who is responsible for this, and the mechanics of how this spreads.
  • Transmission is a consequence of the viral shedding by people in a setting, their activities and interactions and the environmental conditions, but we don’t know the relative importance of all of these aspects.

As we move to a situation where transmission is marked by local clusters rather than a population scale epidemic it is critical that we understand the detail of how and where transmission is happening, and the effectiveness of the raft of measures to control it.

At the moment measures include hand hygiene, surface cleaning, ventilation, distancing and face coverings, yet we don’t know if these measures have equal effects or whether one or more are more important than the others.

How we are doing it

Theme 2 will develop and apply new approaches to understanding the mechanisms for environmental transmission and evaluate the strategies to control them, with an aim to quantify ‘COVID secure’ from a combined mechanistic and epidemiological perspective. The team will ultimately develop quantitative models that predict risk at a local, regional and population scale that are based on the physics and virology of the transmission process.

Work package summaries

Find out about our individual work packages, and explore our reports, evidence and gaps for future study.



Theme leads

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