Infectious SARS-CoV-2 in air and on surfaces in London hospitals

Simon Collins, HIV i-Base

A prospective cross-sectional observational study collected both air samples and swabs from multiple hospital sites occupied by people hospitalised with COVID-19 as well as general areas of a London hospital.

The results were reported by Jie Zhoi and colleagues from Imperial College London and reported on 8 July 2020 in Clinical Infectious Diseases.

Surfaces included bed rails, clinical monitoring devices (blood pressure monitors), ward telephones, computer keyboards, clinical equipment (syringe pumps, urinary catheters), hand-cleaning facilities (hand washing basins and alcohol gel dispensers), with air sampled in immediate vicinity.

All areas were disinfected daily with an additional twice daily disinfection of high touch surfaces using a combined chlorine-based detergent/disinfectant.

Between 2 – 20 April 2020, during the peak of the epidemic, viral RNA was detected on 114/218 (52.3%) of surfaces and 14/31 (38.7%) air samples. However, no virus was cultured, likely due to lower concentrations (all corresponding to an E gene copy number of <105 per mL.

Samples were more likely to be positive in COVID-19 wards than other areas (67/105 (63.8%) vs. 29/64 (45.3%); OR 0.5, 95% CI: 0.2 to 0.9, p=0.025.

These results supported the need for effective use of PPE, physical distancing, and hand/surface hygiene.


Zhou J et al. Investigating SARS-CoV-2 surface and air contamination in an acute healthcare setting during the peak of the COVID-19 pandemic in London. Clinical Infectious Diseases, ciaa905, DOI: 10.1093/cid/ciaa905. (08 July 2020). 

This report was first published on 12 July 2020.


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