Written By: Gerami D Seitzman MD
Review of: Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1 . Van Doremalen N, Bushmaker T, Morris D, et al. New England Journal of Medicine, March 2020
The aerosol and surface stability of SARS-CoV-2, the virus that causes COVID-19, was evaluated in this study.
Ten experimental conditions, performed in triplicate, in 5 environments: aerosol, plastic, stainless steel, copper, and cardboard were tested. Aerosols smaller than 5 µm containing SARS-CoV-2 or SARS-CoV-1 were generated with the use of a 3-jet Collison nebulizer and fed into a Goldberg drum to create an aerosolized environment. The inoculum resulted in cycle-threshold values between 20 and 22, similar to those observed in samples obtained from the upper and lower respiratory tract in humans.
The authors found that SARS-CoV-2 remained viable in aerosols throughout 3 hours of the experiment, with a reduction in infectious titer over time. The virus was detectable on plastic and stainless steel with decreased titers at 48 hours and still detected at 72 hours. No viable virus was detected on cardboard after 24 hours or on copper after 4 hours.
Both SARS-CoV-2 and SARS-CoV-1 had similar half-lives in aerosols, with median estimates of approximately 1.1 to 1.2 hours.
The study design is limited in that experimental settings may not accurately replicate real-life viral loads and stability.
The clinical ophthalmologic environment contains many stainless steel and plastic surfaces. These surfaces are in close contact with patients’ respiratory tracts, for example during slit lamp examination. These findings indicate aerosol and fomite transmission of SARS-CoV-2 may be possible. All surfaces should be decontaminated before and after each patient contact. Speaking during clinical examination and aerosol-generating procedures should be limited or avoided all together.
American Academy of Ophthalmology