The Amoy Gardens SARS outbreak is an important lesson in our current response to COVID-19. SARS-CoV was the first identified severe acute respiratory syndrome coronavirus and is therefore important in understanding the current coronavirus (SARS-CoV-2). Amoy Gardens is a high-rise, densely populated housing estate in Hong Kong that became a site of the second major outbreak of the SARS virus (the first being at the Prince of Wales Hospital). A man infected with SARS and presenting with diarrhoea symptoms is believed to be the source of the outbreak in Amoy Gardens. Rapid spread to other residents is believed to have happened through defective plumbing and sewage systems which released aerosols infected with the SARS virus around the complex through ventilation systems in the building. 73% of Amoy Gardens patients presented with diarrhoea, compared to 20% in the Prince of Wales Hospital. The mortality rate for Amoy Gardens patients was also significantly higher at 13%, compared to 3% in the Prince of Wales Hospital.
So, what does this mean in the current struggle COVID-19 pandemic?
Clinical studies have found positive SARS-CoV-2 RNA in stool in up to 53.42% of patients and has continued to test positive for up to 33 days after negative respiratory samples (Gastroenterology, The Lancet). Many studies have therefore warned of a fecal-oral transmission route of SARS-CoV-19.
Aerosolization of contaminated faeces was a major reason for spread of SARS in Amoy Gardens. Studies have shown a bedpan washer-disinfector failure rate of up to 33%, and the release of steam when washing could present a serious infection control risk if contaminated with the virus. This puts care homes and hospitals at a particularly high-risk of disease spread. Even if patients are not presenting respiratory symptoms, or there are effective measures in place to prevent respiratory spread, fecal aerosolization could spread the virus as happened with SARS in Amoy Gardens.
How can we prevent spread of COVID-19 through aerosols from bedpan washer-disinfectors?
Best-practice guidelines released by the WHO advocate the use of single-use devices with COVID-19 patients. Hospitals and care homes should therefore exclusively use single-use, or one-way, processes with COVID-19 patients to reduce risk of transmission.
Wu, Yongjian; Guo, Cheng; Tang, Lantian; Hong, Zhongsi; Zhou, Jianhui; Dong, Xin. “Prolonged presence of SARS-CoV-2 viral RNA in faecal samples”, The Lancet, March 19, 2020. https://doi.org/10.1016/S2468-1253(20)30083-2.
Xiao F, Tang M, Zheng X, Liu Y, Li X, Shan H. “Evidence for Gastrointestinal Infection of SARS-CoV-2”. Gastroenterology. 2020;S0016-5085(20)30282-1. doi:10.1053/j.gastro.2020.02.055
Jessica Hamzelou. “How long does coronavirus stay on surfaces and can they infect you?” New Scientist. 25 March 2020. https://www.newscientist.com/article/2238494-how-long-does-coronavirus-stay-on-surfaces-and-can-they-infect-you/
“Severe Acute Respiratory Syndrome (SARS) - multi-country outbreak - Update 33” World Health Organisation. 18 April 2003. https://www.who.int/csr/don/2003_04_18/en/
S S C Chim, S K W Tsui, K C A Chan et al. “Genomic characterisation of the severe acute respiratory syndrome coronavirus of Amoy Gardens outbreak in Hong Kong” The Lancet 362, 939