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Bradwell HL, Johnson CW, Lee J, Soler-Lopez M & Jones RB.
Potential transmission of SARS-CoV-2 via robot pets in care homes. 2020
1
Uploaded to ResearchGate August 2020
Potential transmission of SARS-CoV-2 via robot pets in care homes.
Authors: Hannah Louise Bradwell1*, Christopher W. Johnson2, John Lee2, Mar Soler-Lopez3
and Ray B. Jones1
1 Centre for Health Technology, University of Plymouth, Plymouth, Devon, UK
2 Department of Microbiology, Royal Cornwall Hospital, Truro, Cornwall, UK
3Faculty of Health, University of Plymouth, Plymouth, Devon, UK
* Corresponding author: hannah.bradwell@plymouth.ac.uk, christopher.johnson12@nhs.net,
john.lee14@nhs.net, mar.soler-lopez@plymouth.ac.uk, ray.jones@plymouth.ac.uk
Xiao and Torok rightly put limiting person-to-person transmission as the first measure to
control COVID-19 (1). Older adults have been particularly susceptible to SARS-CoV-2, with
dramatic case fatality rates reported, and care homes presenting challenges for preventing
its spread (2,3). Although there is published advice about SARS-CoV-2 persistence on various
surfaces (4,5), we have not yet seen publications regarding persistence on soft, artificial fur-
type surfaces, like those used for robot pets.
Robot pets (e.g. Paro the seal and Joy for All cat and dog) may benefit care home residents,
improving wellbeing and reducing loneliness, agitation and depression (6). Such devices
could therefore reduce loneliness and depression among older adults resulting from social
distancing (3). Their use is becoming widespread (7) and care home staff have informed us
that their robot pets are indeed demonstrating particular usefulness at present, assisting
with loneliness and depression in the absence of usual visitors or scheduled activities.
However, while robot pets could assist in this regard, they are often a shared resource,
passed between residents and staff. The plausibility of SARS-CoV-2 transmission on fomites
therefore raises implications for such devices.
We previously carried out empirical work demonstrating that robot pets could transmit
bacteria between care home residents, and tested the efficacy of a cleaning procedure to
stop it (8). We included eight different devices with varying surfaces (plastics, polyester,
acrylic, and lurex). To understand microbial load following standard use in care homes, we
sampled from the robots following 20 minutes of group interaction with four care home
residents. Colony counts and CFU/cm2 calculations suggested that during this short
interaction robots acquired unacceptable levels of bacterial contamination. Although our
study focussed on bacteria and not viruses, it nevertheless indirectly raises the possibility of
a significant source of viral transmission in long-term care facilities.
In the second stage of our work, we tested our cleaning procedure on contaminated devices
(8). This procedure used two disinfectant products; PDI Super-Sani Germicidal Cloths (9) and
Ecolab Sirafan Speed spray (10). We removed visible dirt with PDI wipes, before robots were
sprayed with the Ecolab spray, and brushed in a head-to-tail direction with a solid plastic
brush to disperse disinfectant. Devices were allowed to air dry before PDI wipes were
vigorously applied to all areas, in a head-to-tail direction, to ensure complete coverage and
fur fibre contact through the depth of the covering. Devices were maintained wet for 2
minutes, with wipes replaced upon drying. The results strongly supported cleaning efficacy,
with CFU/cm2 falling well within the acceptable threshold on all devices.
Bradwell HL, Johnson CW, Lee J, Soler-Lopez M & Jones RB.
Potential transmission of SARS-CoV-2 via robot pets in care homes. 2020
2
Uploaded to ResearchGate August 2020
Although we did not test for viruses, in particular SARS-CoV-2, we have reviewed the
cleaning products we used against the USA Environment Protection Agency List N of
Disinfectants for Use Against SARS-CoV-2 (11). PDI Super-Sani Germicidal Cloths have an EPA
number and are included on List N, confirming that the product is registered as an agent
meeting EPA criterion for use against SARS-CoV-2.
However, we could not find an EPA number for the Ecolab Sirafan Speed spray. Ecolab
Sirafan Speed spray has a chemical composition of 35% 2-propanol and 25% 1-propanol.
Kampf et al. (5) reported that a biocidal agent with a “combination of 45% 2-propanol with
30% 1-propanol [sic], readily inactivated [SARS-CoV] coronavirus infectivity by
approximately 4 log10 or more” in 30 seconds in suspension tests. This was similar to the
effect of Ethanol at 80% or Sodium Hypochlorite (bleach) at 0.21%. Given that the Ecolab
Sirafan Speed spray’s composition is only 35% 2-propanol and 25% 1-propanol it may
therefore not be effective against SARS-CoV-2, although we cannot confirm this without
more research.
Due to potential limitations of the Ecolab spray in combatting this virus, it is possible the
order of application should change from our original procedure, to prioritise use of the PDI
wipes first and avoid brushing any SARS-CoV-2 contamination further through the soft
materials before adequate disinfectant is applied. Maintaining use of the Ecolab spray
secondarily would still be beneficial for bacterial control.
Robot pets may be particularly useful during this pandemic and consequential isolation, but
safety must be prioritised, and shared use of such devices appears unsafe at present. We
are aware and concerned that robot pets are still in use in care homes, and often kissed and
cuddled. We are also unaware of SARS-CoV-2 advice being provided by the main robot pet
producers. We therefore report an urgent need for empirical investigation of SARS-CoV-2
transmission on robot pets and immediate action within care homes to respond to this
identified risk, particularly to remove devices from shared use.
References
1. Xiao Y, Torok ME. Taking the right measures to control COVID-19. The Lancet
Infectious diseases. 2020;20(5):523-4.
2. Aprahamian I, Cesari M. Geriatric Syndromes and SARS-COV-2: More than Just Being
Old. J Frailty Aging. 2020:1-3.
3. Wang H, Li T, Barbarino P, Gauthier S, Brodaty H, Molinuevo JL, et al. Dementia care
during COVID-19. The Lancet. 2020;395(10231):1190-1.
4. Kampf G, Todt D, Pfaender S, Steinmann E. Persistence of coronaviruses on
inanimate surfaces and their inactivation with biocidal agents. Journal of Hospital Infection.
2020;104(3):246-51.
5. van Doremalen N, Bushmaker T, Morris DH, Holbrook MG, Gamble A, Williamson BN,
et al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New
England Journal of Medicine. 2020;382(16):1564-7.
Bradwell HL, Johnson CW, Lee J, Soler-Lopez M & Jones RB.
Potential transmission of SARS-CoV-2 via robot pets in care homes. 2020
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Uploaded to ResearchGate August 2020
6. Abbott R, Orr N, McGill P, Whear R, Bethel A, Garside R, et al. How do “robopets”
impact the health and well-being of residents in care homes? A systematic review of
qualitative and quantitative evidence. International Journal of Older People Nursing.
2019;14(3):e12239.
7. Bradwell HL, Winnington R, Thill S, Jones RB. Longitudinal diary data: Six months
real-world implementation of affordable companion robots for older people in supported
living. Companion of the 2020 ACM/IEEE International Conference on Human-Robot
Interaction (HRI ’20 Companion); 2020 23-26 March 2020; Cambridge, UK.
8. Bradwell HL, Johnson, CW, Lee J, Winnington R, Thill S, Jones RB. Infection control
study of Paro and other companion robot animals for use in care homes: Efficacy of a
cleaning procedure. PLOS ONE. 2020;15(8): e0237069.
https://doi.org/10.1371/journal.pone.0237069
9. PDI I. Super Sani-Cloth® Germicidal Disposable Wipe: PDI Healthcare; 2020. Available
from: https://pdihc.com/products/environment-of-care/super-sani-cloth-germicidal-
disposable-wipe/.
10. Ecolab. Sirafan Speed RAPID SURFACE DISINFECTANT, RINSE FREE; 2008. Available
from: https://www.essef.be/images/documenten/9033070_pf1_E.pdf.
11. United States Environmental Protection Agency; Pesticide Registration; List N:
Disinfectants for Use Against SARS-CoV-2; 2020. Available from:
https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2.