Catherine Noakes and the Scientific Advisory Group for Emergencies (SAGE)

Six guest lecturers will be joining Jonathn Van-Tam for this year's lectures. Lab News interviewed both Sharon Peacock and Catherine Noakes. The other four British experts are pictured above.

During the pandemic, Prof Catherine Noakes used her research expertise in building physics and environmental engineering to understand how building design and ventilation can reduce the risk of SARS-CoV-2 virus transmission.

As co-chair of the Environment and Modelling sub-group of the UK government’s Scientific Advisory Group for Emergencies (SAGE), Catherine provides advice on how the virus transmits and the best strategies to control the spread.

Q: What role did you and your team play during the pandemic?

A: We have mainly been involved in the detail of understanding how the virus transmits and how we can use mitigations such as ventilation, masks, distancing and hand and respiratory hygiene to control the disease. This ranged from leading research studies based on modelling risk, through to collating the evidence on transmission from multiple studies worldwide to provide science advice to government through my role in chairing the Environment and Modelling sub-group (EMG) of SAGE. 

Q: How did you get involved?

A: I have worked on airborne infection and ventilation for around 20 years so, prior to the pandemic, I had already worked on studies looking at how the indoor environment influences risks for diseases such as TB and Influenza. In April 2020, I was asked to prepare a paper for the UK government SAGE committee on environmental transmission of COVID-19. This led to the formation of EMG, and I have been involved ever since.

Q: What was the focus of your work?

A: I have worked with multiple different teams and projects over the past 20 months with a focus on looking at the physics of respiratory droplets and aerosols and how they are affected by the environment and human behaviour. A lot of our work has focused on modelling. We have used Computational Fluid Dynamics methodologies to carry out detailed simulation of the emission, evaporation, transport and deposition of the range of different sizes of droplets and aerosols that are emitted when we breathe, talk and cough. This allows us to understand how these aerosols are affected by things like temperature and humidity as well as, for example, how the ventilation in a room or the location of a Perspex screen affect the exposure to virus that is carried in these aerosols. We also carry out risk modelling which considers the exposure to virus through different routes, in the air and via hands and surfaces, to understand the likelihood of transmission in different circumstances. This modelling links together with multiple other studies that are looking at measuring data from human emissions, assessing behaviour in different settings, characterising survival of the virus, and assessing the impact of specific interventions. We need studies in all of these areas to be able to put together all the pieces of the jigsaw on how and where transmission happens and how best to control it.

Q: What challenges did you face?

A: Transmission of respiratory disease is a large and complex problem that needs input from many different experts. Although we have a fairly good idea of the key principles that affect transmission, there are still many details missing. We are also trying to work out how transmission happens and how effective different measures are very quickly in order to support public health messaging. So, research has had to happen in timescales that are far quicker than usual, and with real-world data that is messy and changes all the time due to national and local measures that are put in place. The body of research on SARS-CoV-2 is enormous and sifting through this information to bring together all the different pieces of knowledge is a real challenge. 

Q: How did you overcome those challenges?

A: Collaboration has been key to tackling some of these challenges. There has been a huge international effort working together to share knowledge and expertise across disciplines and bring researchers together. I am proud to be part of a large national collaboration, the PROTECT National Core Study on Transmission and the Environment, which brings together over 100 researchers from multiple organisations across a range of related projects. This allows us to explore many different aspects of transmission and provides a forum for sharing expertise and knowledge across different elements of transmission. I have also worked with an amazing group of scientists around the world on a number of papers, where we have particularly raised the importance of airborne transmission and the need to think about how we design and manage buildings better to mitigate transmission risks through ventilation.

Q: What impact did your project have on the overall pandemic?

A: I think the work we have been involved with over the course of the pandemic has had quite a significant impact. Throughout, we have collated evidence from our own research and for research conducted by multiple other people to provide the most up to date evidence on the mechanisms for transmission and the effectiveness of interventions to policy makers and to the public. We use all this knowledge to make a judgement on the likelihood that particular processes will happen or how particular mitigation strategies are likely to work. Although there is uncertainty in this, we have used the best international evidence to support national policies for workplaces, homes and social settings.

Catherine Noakes is Professor of Environmental Engineering for Buildings at the University of Leeds and co-chair of the Environment and Modelling sub-group of the UK government’s Scientific Advisory Group for Emergencies (SAGE) gov.uk/government/organisations/scientific-advisory-group-for-emergencies

Read our coverage on this year's Christmas lectures with Jonathan Van-Tam

Read the companion editorial: Sharon Peacock and the COVID-19 Genomics UK Consortium (COG-UK)