Just presented two case studies on COVID-19 spread in buildings as part of the MRC-CSIR COVID-19 and Facilities Management series of lectures. The research includes the following findings:

• Space: In a crowded indoor space with poor ventilation it appears that infections can happen across distances of greater than 2m.
• Time: The amount of time spent in the same space with an infected person increases the likelihood of infection.
• Ventilation: Poor ventilation and recirculated air appears to be a significant contributing factor to increased risks of infection.

These findings should be perhaps be emphasized in guidance that indicates that:

• All crowded indoor spaces increase the likelihood of infection and should be avoided.
• Where this is unavoidable, spaces should be very well ventilated, ideally with open doors and windows directly to the outside.
• The length of time spent in crowded spaces should be minimised.

References for the case studies are outlined below.

Park SY, Kim YM, Yi S, Lee S, Na BJ, Kim CB, et al. Coronavirus disease outbreak in call center, South Korea. Emerg Infect Dis. 2020 Aug [date cited]. https://doi.org/10.3201/eid2608.201274

Yuguo Li1*† , Ph.D.; Hua Qian2† , Ph.D.; Jian Hang3† , Ph.D.; Xuguang Chen4 , M.Sc.; Ling Hong3 , Ph.D.; Peng Liang5 , M.Sc.; Jiansen Li4 , M.Sc.; Shenglan Xiao1 , Ph.D.; Jianjian Wei6 , Ph.D.; Li Liu7 , Ph.D.; and Min Kang4† , M.Sc.(2020). Evidence for probable aerosol transmission of SARS-CoV-2 in a poorly ventilated restaurant [ONLINE] Available at: https://www.medrxiv.org/content/10.1101/2020.04.16.20067728v1.full.pdf [Accessed 6/7/2020].

Javier Salas, Mariano Zafra, (2020). An analysis of three Covid-19 outbreaks: how they happened and how they can be avoided | Science Tech | EL PAÍS in English [ONLINE] Available at: https://english.elpais.com/spanish_news/2020-06-17/an-analysis-of-three-covid-19-outbreaks-how-they-happened-and-how-they-can-be-avoided.html [Accessed 6/7/2020].