March 24, 2020

expert reaction to CDC report on COVID-19 outbreaks on cruise ships, which includes that SARS-CoV-2 RNA was identified on surfaces in cabins up to 17 days after they were vacated

The US Centre for Disease Control (CDC) has published a report on the COVID-19 outbreaks on cruise ships, which includes that SARS-CoV-2 RNA was identified on surfaces in cabins up to 17 days after they were vacated.

Dr Julian Tang, Associate Professor of Respiratory Sciences at the University of Leicester said:

“It is highly unlikely that after 17 days SARS-CoV-2 would survive on plastic or metal surfaces – according to a new study published in the New England Medical Journal¹, the virus survives for no longer than 96 hours (4 days), so the any successful transmission of live virus after four days from such surfaces would be very unlikely.”

1. https://www.nejm.org/doi/full/10.1056/NEJMc2004973?query=featured_home 

Prof William Keevil, Professor of Environmental Healthcare, University of Southampton, said:

“We have to be very careful in interpreting these new data and similar data on shedding published elsewhere. The routine test uses RT-PCR which measures a small fragment of the coronavirus genome. It does not tell us if an intact viable virus was present and it is known that patients can shed viral RNA days after infection has ceased. Nevertheless, it does indicate that coronavirus was present in these cabins and was also associated with asymptomatic infected carriers: only a few of us have cautioned from the very start that these could be important spreaders. Indeed, my first correspondence to the Science Media Centre about this was 24th January when the first important paper from Wuhan was published.

“Data are beginning to be published on possible fomite transmission form inanimate surfaces to susceptible people in public areas. In addition, we showed survival of human coronavirus 229E on plastics, ceramics, stainless steel and glass for 4-5 days¹.  Duan et al.² showed SARS-CoV-1 survived 5 days on wood, paper, plastic and glass surfaces. Now van Doremalan et al.³ have reproduced these results for SARS-CoV-2. So fomite transmission on contaminated surfaces from hands to eyes, nose and mouth is possible and is a major reason why everyone has been urged to wash their hands rigorously and repeatedly throughout the day; and of course to regularly clean common contact surfaces such as stair rails, door handles and push plates.”

1. Warnes S, Little Z, Keevil C. (2015). Human coronavirus 229E remains infectious on common touch surface materials.  mBio 2015;6:e01697-15.    

2. Duan S, Zhao X, Wen R, et al. Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation. Biomed Environ Sci 2003;16:246-55.

3. Doremalen N, Bushmaker T, Morris D, et al.  Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. N Engl J Med. March 17, 2020; DOI: 10.1056/NEJMc2004973

Prof Paul Digard, Chair of Virology, The Roslin Institute, University of Edinburgh, said:

“It’s very important to remember that viral RNA will survive longer than actual infectious virus. In the case of influenza virus, which shares many biochemical properties with SARS-CoV-2, as well as the ability to be spread via surface contamination, research has shown that viral RNA lasts for days on surfaces but the infectivity of the virus drops off exponentially and is largely gone after a few hours.

“I’ve copied a figure from our own version of this type of study¹ to illustrate – RNA on the left, live virus on the right.”

1. http://dx.plos.org/10.1371/journal.pone.0027932

* https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e3.htm?s_cid=mm6912e3_w

All our previous output on this subject can be seen at this weblink: 

www.sciencemediacentre.org/tag/covid-19/

Declared interests

None received.