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

Summary

The following is a short summary of the best available evidence from trusted sources that have been rated as providing high quality information on the risk of transmission for COVID-19 on infected surfaces. One systematic review, one rapid review, one literature review, one international guidance, two national guidance, one professional organization and one single study were found to answer this question and were used in this REAL Summary. 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 [4,5]. In the Transmission Modes of COVID-19: A Systematic Review (September, 2020), the authors state that there are five potential modes of transmission of COVID-19 including: airborne, droplet, contact with contaminated surfaces, oral and fecal secretions [1]. Both droplet and contact with contaminated surfaces were the most common transmission modes of COVID-19 [1]. However, the authors of the SARS-CoV-2 in environmental samples of quarantined households (June, 2020) 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, SARS-CoV-2 viability under different meteorological conditions, surfaces, fluids and transmission between animals (October, 2020) notes that SARS-CoV-2 may persist on copper surfaces for up to four hours and on stainless steel for 2 days [3]. 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 [2]. Guidance from the Government of Canada COVID-19 signs, symptoms and severity of disease: A clinician guide (September, 2020), states that the duration of possible infection on surfaces is dependent on the type of surface, relative temperature and humidity of the environment [5]. The Harvard Medical School also notes that it remains unknown how sunlight, heat, or cold affects viral survival times [6].  
 
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 (February, 2020), 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 [2]. Other biocidal agents such as 0.02% chlorhexidine digluconate and 0.005-0.2% benzalkonium chloride are less effective [2]. The Government of Canada notes that SARS-CoV-2 is easily inactivated by store-bought disinfectants or diluted bleach solutions [5]. The Harvard Medical School (HMS) recommends that frequently touched surfaces including counters, tabletops, doorknobs, bathroom fixtures, phones, etc. should be disinfected daily [6]. 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 [6]. It is important to understand that soap and water does not inactivate the virus, but rather removes it from a surface [6]. The Centers for Disease Control and Prevention note in its Running Essential Errands (December, 2020) 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 [7]. 

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.  
 
McGill University has published an article, “Disinfectants: To Spray or Not To Spray, That Is The Question” (December, 2020), which describes the challenges with knowing how important infected surfaces are to the spread of SARS-CoV-2. It also describes what spraying should be done and in what scenario to reduce both environmental harm and harm to human health.  

Organizational Scan

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 [9].  
 
Cicada, a UK based company has partnered with Signo NanoCare UK Ltd to develop a virus-resistant nano-coating. This coating would be placed over the surface of a base material to not only make a material easier to clean since it repels liquid and dirt, but also to provide an antimicrobial layer that constantly kill viruses, bacteria, moulds and fungi. A treated surface would provide antimicrobial protection for at least 12 months [10].  

Review of Evidence

Resource	Type/Source of Evidence	Last Updated
Transmission Modes of COVID-19: A Systematic Review — Mehraeen et al.	Systematic Review	Five potential modes of transmission of COVID-19 are identified. These include airborne, droplet, contact with contaminated surfaces, oral and fecal secretions.   Droplet and contact with contaminated surfaces were the most common transmission modes of COVID-19.   Some studies have identified other modes of virus transmission including person to person and direct contact with animals. Last Updated: August 31, 2021
Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents — Kampf et el.	Rapid Review	SARS-CoV-2 on infected surfaces may be inactivated 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: February 19, 2020
SARS-CoV-2 viability under different meteorological conditions, surfaces, fluids and transmission between animals — Fernández-Raga et al.	Literature Review	Findings suggest that SARS-CoV-2 may survive on stainless steel for 3 days and copper for 4 hours.   Last Updated: October 1, 2020
Transmission of SARS-CoV-2: implications for infection prevention precautions — WHO: World Health Organization	International Guidance	Transmission of the SARS-CoV-2 can occur through direct, indirect or close contact with infected people though respiratory droplets expelled from n infected individual through coughs, sneezes, talking or singing.   Airborne transmission can occur if a susceptible person inhales aerosols and could become infected if the aerosols contained enough virus to cause infection.  Transmission may also occur indirectly if a person touches a surface or object that was previously contaminated by an infected person and then touches their mouth, nose or eyes.   Viable SARS-CoV-2 can be found on surfaces for hours to days and depend on the temperature, humidity and type of surface.   Last Updated: July 8, 2020
COVID-19 signs, symptoms and severity of disease: A clinician guide — Government of Canada	National Guidance	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: September 17, 2020
COVID-19 Basics — Harvard Health Publishing: Harvard Medical School	Professional Organization	The COVID-19 virus mainly spreads from person to person and means it can be transmitted via aerosols when a person breathes or talks or from contact with infected surfaces.   Cleaning frequently touched surfaces every day including counters, tabletops, doorknobs, bathroom fixtures, phones, etc. is recommended.   One can prevent contamination of surfaces by frequently washing their hands with soap and water after touching a potentially infected surface.  Last Updated: December 2, 2020
Running Essential Errands — CDC: Centers for Disease Control and Prevention	National Guidance	Masks should be worn while shopping and social distancing rules abided by.   If possible, one should limit in-person visits to grocery stores and other stores selling household essentials.   An alternative 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: December 30, 2020
SARS-CoV-2 in environmental samples of quarantined households — Dōhla et al.	Single Study	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
Collingwood Hospital to use Latest Technology to Prevent Infections — Collingwood General and Marine Hospital	Organizational Scan	Last Updated: May 12, 2019
Cicada’s Antimicrobial Nanotechnology Solution for COVID-Free Surfaces — AZO NANO	Organizational Scan	Last Updated: December 15, 2020
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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