The transmission of Covid-19 is thought to occur mainly through respiratory droplets generated by coughing and sneezing, and through contact with contaminated surfaces. The predominant modes of transmission are assumed to be aerosol, droplet and contact.
Survival rates of the virus vary on different surface types and in different environmental conditions. Learning in museums focuses a lot on touch, handling and sensory experiences, all of which could enable transmission, and need to be risk assessed and the risk mitigated.
It is worth noting that research published in the Lancet on the 29 September has found a lower risk that previously thought for touch transmission in real life conditions.
To begin your enhanced Risk Assessment process, consider:
- Which objects, materials and surfaces are regularly handled or breathed on by staff or members of the public?
- What are they made from, and how long does the virus survive on those materials?
- In what environmental conditions do the handling happen?
Research on virus survival on difference surfaces
The tables below show current research on the length of time the virus survives on different surfaces – results vary slightly across studies. The information should help you assess what actions may be most appropriate for you to take in your own situation.
Environmental conditions play a part in how long the virus survives. It lives longer on smoother surfaces, like plastic. Freezing (or a freeze-thaw cycle) doesn’t destroy the virus and, as this is the usual method of disposing of unwanted pests in museums, other methods need to be considered. At lower temperatures, the virus seems more stable (4°C survival rate is up to 2 weeks) and is destroyed quickly by high temperatures (70°C survival rate is 5 minutes).
Study: Stability of SARS-CoV-2 in different environmental conditions
At a standard 22°C and relative humidity of 65% it survives for the timescales set out below:
|Surface||Time to no viable virus|
|Fabric & wood||24 hours|
|Plastic & stainless steel||7 days|
Study: Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1
|Surface||Time to no viable virus|
|Copper||4 hours = no viable virus|
|Cardboard||24 hours = no viable virus|
|Stainless steel||48 hours = 100.6 TCID50 per millilitre of medium|
|Plastic||72 hours = 100.6 TCID50 per millilitre of medium|
To gain the above times the researchers used chemicals to retrieve the surviving virus, so they indicate this is not necessarily the same for a casual contact during an object being handled. This will have an impact on objects being used or stored in temperature-controlled museum stores. Relative humidity has been found to have no impact (speeding or slowing) on the decay rate of the virus.
Sunlight speeds up the destruction of the virus in the air, but sunlight is not good conservation for many objects or artworks. Studies have used simulated sunlight on air droplet transmission (not by touch) and shown that in the average light-levels of an autumn day, there is a 90% destruction rate within 19 minutes, rising to 90% destruction in 6 minutes for a sunny day in high summer. This research is worth considering when managing the wider learning environment, along with air circulation within spaces.
 Stability of SARS-CoV-2 in different environmental conditions. Open Access Published: April 02, 2020DOI: https://doi.org/10.1016/S2666-5247(20)30003-3
 Survival of COVID-19, SARS-CoV-2 on surfaces, Van Doremalen N, Morris D, Holbrook M et al. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. NEJM 2020. The Pharmaceutical Journal, April 2020, Vol 304, No 7936, online | DOI: 10.1211/PJ.2020.20207889. doi: 10.1056/NEJMc2004973
 Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces. The Journal of Infectious Diseases, Volume 222, Issue 2, 15 July 2020, Pages 214–222, https://doi.org/10.1093/infdis/jiaa274 Published: 20 May 2020