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Updated: September 7, 2020

What is the risk of transmission for COVID-19 on infected surfaces?

Summary

The following is a summary of evidence sources that provide high quality information on the risk of transmission for COVID-19 on infected surfaces. For additional information about each of the sources, see the Table below.

According to the World Health Organization and the Government of Canada, the transmission of COVID-19 occurs when the virus enters a person’s body via respiratory droplets containing the virus that adhere to the mucous membrane of a person’s eyes, nose or mouth, or through indirect contact by touching a contaminated surface or object, then touching one’s eyes, nose or mouth [3,4]. The authors of the Sustainability of Coronavirus on Different Surfaces review found that infected surfaces are a major source of coronavirus transmission [2]. In contrast, the authors of the SARS-CoV-2 in environmental samples of quarantined households study found that indirect environmental transmission may only play a minor role in SARS-CoV-2 transmission, based on their analysis that only 3.36% of household objects and 15% of wastewater samples tested positive for the virus among 21 households quarantined with COVID-19 positive cases [8]. This mode of transmission is the subject of ongoing investigation.  
 
One review, one single study and a report from the Harvard Medical School agree that SARS-CoV-2 may persist on copper surfaces for up to four hours and on cardboard for up to 24 hours [2,5,7]. Although length of time varied, estimates indicate that SARS-CoV-2 may persist on stainless steel and plastic surfaces for 2 and 3 days respectively [2,5,7]. The authors of one review state that some coronavirus strains persist on wood for 4-5 days and other metals for 5 days, but it remains unknown if this is the case with SARS-CoV-2 [1]. Guidance from the Government of Canada,  Coronavirus disease (COVID-19), states that the duration of possible infection on surfaces is dependent on the type of surface, relative temperature and humidity of the environment [4]. The Harvard Medical School also notes that it remains unknown how sunlight, heat, or cold affects viral survival times [5].  A brief report on the  Stability of SARS- CoV-2 in different environmental conditions found that the time for virus inactivation was reduced when exposed to heat and is most stable on smooth surfaces (e.g., the infectious virus could not be detected on glass after four days or stainless steel and plastic after seven days) [9]
 
There is consensus that disinfectant and soap are effective in preventing transmission from surfaces. The authors of a review on the Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents, suggest that coronaviruses on infected surfaces can be inactivated by surface disinfection procedures with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within one minute [1]. Other biocidal agents such as 0.02% chlorhexidine digluconate and 0.005-0.2% benzalkonium chloride are less effective [1]. The Government of Canada notes that SARS-CoV-2 is easily inactivated by store-bought disinfectants or diluted bleach solutions [4]. The Harvard Medical School (HMS) recommends that frequently touched surfaces including counters, tabletops, doorknobs, bathroom fixtures, phones, etc. should be disinfected daily [5]. To prevent further contamination of surfaces, HMS recommends handwashing for 20 seconds with soap and water after touching potentially infected surfaces (i.e. mail, packages, etc.) and objects in external settings such as the grocery store [5]. It is important to understand that soap and water does not inactivate the virus, but rather removes it from a surface [5]. The Centers for Disease Control and Prevention note in its Running Essential Errands guidance that one can also take advantage of technology to limit the amount of times we touch a potentially infected surface by ordering online, using curbside pickup, and online banking [6]

Evidence

What‘s Trending on Social Media and Media

This CTV article describes four common surfaces including cardboard, copper, plastic and stainless steel and the amount of time SARS-CoV-2 remains active. Cleansing and disinfecting these surfaces regularly is important, and the Centers for Disease Control and Prevention recommends that surfaces be cleaned using water with soap or alcohol solutions that contain at least 70% alcohol. A list of approved and effective household disinfectants can be found here.   
 
A former emergency room nurse, Molly Lixey, in Michigan made a Facebook video demonstrating how cross contamination can occur at a grocery store even while wearing gloves. This scenario was simulated using paint to mimic the germs being picked up through the grocery shopping process. This video currently has over 1.8 million Facebook views and over 75,000 shares since being published on April 4th, 2020. Many others are also taking to social media to help educate about the importance of hand hygiene as seen in several TikTok videos. More information can be found here

Organizational Scan

The Haliburton, Kawartha, and Pine Ridge District Health Unit has reported no findings of transmission through household items like groceries, but they still recommend proper hygiene in disinfecting any potentially contaminated surfaces. Some of these recommendations include washing hands before handling any foods, and washing any unpackaged fruits and vegetables under cold running water [10]
 
As of May 2019, Collingwood General and Marine Hospital unveiled newly renovated patient rooms which included a variety of bacteria and infection prevention features. Door handles, bed rails, and toilet seats in patient rooms and public bathrooms were infused with copper. Collingwood General and Marine Hospital was the first hospital in Canada to have these measures in place [11]

Review of Evidence

Resource Type/Source of Evidence Last Updated
Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents
— Kampf et el.
Rapid Review

This review notes that SARS-CoV-2 on infected surfaces may be inactivated by surface disinfection procedures with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Other biocidal agents such as 0.05-0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective.

Findings in this review suggest that coronavirus strains may persist on metal for up to 5 days, wood for 4-5 days, glass for 4 days, plastic for 4-9 days, paper for 24 hours-5 days, hospital gowns for 2 days, latex gloves for up to 8 hours, steel for 2-3 days and copper for up to 4 hours.

Last Updated: June 30, 2020
Sustainability of Coronaviruses on Different Surfaces
— Suman et al.
Rapid Review

This review notes that infected surfaces are a major reason for coronavirus transmission. Metal surfaces can remain contaminated from hours to days. SARS-CoV-2 remained the longest on plastic and stainless steel and least on copper surfaces.     This review notes that the infection capability for SARS-CoV-2 is 3 hours for aerosol, 72 hours for plastic, 48 hours for stainless steel, 4 hours for copper and 24 hours for cardboard. 

Last Updated: May 5, 2020
Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations
— WHO: World Health Organization
International Guidance

The WHO notes that transmission of the COVID-19 virus can occur through indirect contact with surfaces in the immediate environment or with an object used on the infected person (e.g., stethoscope or thermometer).

Last Updated: July 8, 2020
Coronavirus disease (COVID-19)
— Government of Canada
National Guidance

This report notes that the virus enters a person’s body by respiratory droplets containing the virus that adhere to mucous membrane of a person’s eyes, nose or mouth, or by touching a surface or an object contaminated with the virus then proceeding to touching one’s eyes, nose or mouth. Duration of infection on surfaces is dependent on surface type and relative temperature or humidity of the environment. The virus is easily inactivated by store-bought disinfectants or diluted bleach solution prepared daily.

Last Updated: April 12, 2020
COVID-19 Basics
— Harvard Health Publishing: Harvard Medical School
Professional Organization

This report notes that the COVID-19 virus can survive up to four hours on copper, up to 24 hours on cardboard and up to two or three days on plastic and stainless steel. It remains unknown how sunlight and temperature affect survival times.     This report recommends cleaning frequently touched surfaces everyday including counters, tabletops, doorknobs, bathroom fixtures, phones, etc. One can prevent further contamination of surfaces by frequently washing their hands with soap and water after touching a potentially infected surface. 

Last Updated: August 11, 2020
Running Essential Errands
— CDC: Centers for Disease Control and Prevention
National Guidance

If possible, one should limit in-person visits to grocery stores and other stores selling household essentials. An alternatives would be to pre-order, pay online and use curbside pickup or delivery options. For any consultations needed at banks or other services, one should look into potential virtual or telephone meetings and online options. 

Last Updated: August 2, 2020
Aerosol Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1
— van Doremalen et al.
Single Study

This study found that on copper, no viable SARS-CoV-2 was measured after four hours and on cardboard no viable virus was measured after 24 hours. On plastic and stainless steel, viable virus was detected for up to 72 hours, although greatly reduced.

Last Updated: April 15, 2020
SARS-CoV-2 in environmental samples of quarantined households
— Dōhla et al.
Single Study

This study finds that among households quarantined with COVID-19 positive cases, only 3.36% of all object samples in households (e.g., doorknobs, stovetops, remote controls) tested positive for SARS-CoV-2, while 15% of wastewater samples (e.g., washbasin, showers, toilets) tested positive. Of these infected surfaces, the team was unable to grow infectious virus from any of the samples. This study notes that indirect environmental transmission may only play a minor role in SARS-CoV-2 transmission.

Last Updated: June 1, 2020
Stability of SARS- CoV-2 in different environmental conditions
— Chin et al.
Correspondence/Single Study

The authors report that they measured the stability of SARS-CoV-2 at different temperatures varying with time and tested for infectivity on different surfaces after 14 days, in a laboratory setting, with the following results: the virus is sensitive to heat especially at 70 degrees Celsius, reducing time to inactivation to 5 minutes; under constant environmental conditions, no virus was detected on tissues or paper after 3 hours, on wood or cloth after 2 days, and on stainless and plastic after 7 days; a small amount of virus was detectable on a surgical mask after 7 days; in all cases, the virus was highly susceptible to disinfectant.  The virus was also shown to be stable for a wide range of pH values. As this study was conducted under laboratory conditions, the results do not necessarily reflect the potential to pick up the virus on casual contact.  

Last Updated: April 1, 2020
COVID-19 – Q&A
— Haliburton Kawartha Pine Ridge District
Organizational Scan Last Updated: June 3, 2020
Collingwood Hospital to use Latest Technology to Prevent Infections
— Simcoe
Organizational Scan Last Updated: May 12, 2019
Disclaimer: The summaries provided are distillations of reviews that have synthesized many individual studies. As such, summarized information may not always be applicable to every context. Each piece of evidence is hyperlinked to the original source.

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