COVID-19: Surface cleaning
Questions and answers

The purpose of this document is to shed light on the cleaning and disinfection of surfaces in indoor environments, specifically in residential and public spaces, with the exception of healthcare facilities and other care settings. The content of this document is based on the latest available information at the time of writing. Given that the situation and knowledge about the SARS-CoV-2 (COVID-19) are evolving rapidly, it will be updated when required according to scientific developments.

What are the cleaning and disinfection procedures for residential and public spaces with regard to the SARS-CoV-2 virus, which is responsible for COVID-19?

Definitions

Surface cleaning refers to the removal of dirt and impurities, including microorganisms. Cleaning alone does not kill microorganisms. However, by eliminating some of them, cleaning reduces their numbers and thus the risk of spreading infection (Health Canada, 2020a).

Surface disinfection is carried out using chemical products to kill microorganisms. Killing the microorganisms remaining on a surface after cleaning further reduces the risk of spreading infection (Health Canada, 2020a).

Points to keep in mind

• The virus responsible for COVID-19 can survive for some time (a few hours to several days) on various surfaces, but is easily removed by most regular cleaning products and disinfectants.
• Regular cleaning products and disinfectants are effective against the virus that causes COVID-19 (see Health Canada’s list of products to use against COVID-19) (Health Canada, 2020b; 2020c). A solution containing bleach (0.1% to 0.5% dilution of sodium hypochlorite), ethanol (62% to 71%) or hydrogen peroxide (0.5%) may also be used (Kampf et al., 2020). The method for preparing a 0.5% bleach solution is: one part bleach to nine parts water, to be prepared daily.
• Always follow the manufacturer’s instructions for the use of these products, and do not mix different products as they can generate very irritating and toxic fumes.
• Be sure to allow sufficient contact time between the product and the surface to be disinfected. This contact time is usually specified by the product manufacturer (Public Health Ontario, 2020).
• Surfaces that are more frequently touched by occupants are more likely to be contaminated.
• For porous surfaces, such as carpets and curtains, remove all visible contamination where present, and clean with the appropriate cleaning products indicated for use on these surfaces. After cleaning, if the items can be washed, wash them according to the manufacturer’s instructions using, if possible, the hottest water setting appropriate for them (Health Canada, 2020a; CDC, 2020a), and then dry them thoroughly.

Cleaning method in the absence of infected individuals

• Use paper towels or clean towels for cleaning.
• Since disinfectants are less effective when there is dirt, clean the surface with soap and water to remove all visible debris and stains first. Rinse with clear water and wipe with a clean towel. Apply the disinfectant. If the surface is already clean, you can apply the disinfectant immediately. Allow the disinfectant solution to work for a few minutes (according to the manufacturer’s instructions) before wiping off any traces of it with a clean cloth. Start in cleaner areas and then move to dirtier areas (Finnish Institute of Occupational Health, 2020). All frequently touched surfaces (e.g. door handles, chair armrests, tables, light switches, water taps, elevator buttons, stair railings, toilets, etc.) must be cleaned frequently.
• In public spaces where people touch surfaces, cleaning should be done at least daily and, if possible, even more frequently (every 2 to 4 hours) (Finnish Institute of Occupational Health, 2020).
• If possible, avoid the use of vaporizers to limit formation of aerosols from the disinfectant product that could be inhaled and thus irritate the respiratory tract. If such a spray is used, adjust it to obtain a stream of large drops.

Method for cleaning spaces where infected individuals have stayed

In areas where infected people have stayed for several hours, you should suspect that the virus is present on the surfaces. Cleaning procedures must be maximized.

• At present, the scientific community cannot accurately determine the actual survival time of the virus in the open air (Fleury, 2020). However, the median half-life of SARS-CoV-2 in aerosols has been observed to be approximately 1 hour in experimental situations (van Doremalen et al., 2020). There is little evidence in the literature that a SARS-CoV-2 infection can occur via aerosols.  However, considering that these recommendations are dedicated to residential and community settings (outside healthcare settings) where the clinical condition of the infected person is often unknown, that the state of the ventilation is also not known, that the disinfection measures are possibly less rigorous than in healthcare settings and that the personal protective equipment are often not available, it is recommended that areas used by infected individuals be closed as much as possible and that cleaning and disinfection be delayed for at least three hours. If possible, open outside windows to increase air circulation in the area. This waiting period will also allow for a certain level of virus inactivation on the surfaces.
• The same cleaning products and disinfectants can be used for cleaning tasks. Allow sufficient contact time for the disinfectant to inactivate the virus (according to the manufacturer’s specifications).
• For porous surfaces, such as carpets and curtains, remove all visible contamination where present, and clean with the appropriate cleaning products indicated for use on these surfaces. After cleaning, if the items can be washed, wash them according to the manufacturer’s instructions using, if possible, the hottest water setting appropriate for them (Health Canada, 2020a; CDC, 2020b), and then dry them thoroughly.
• Clothes and other items that go to the laundry room can be washed, using hot water if possible (Health Canada, 2020a). Place soiled laundry (e.g. sheets, towels and clothing) in a cloth or plastic bag. Carry the bags to the washing machine. Avoid shaking out the laundry or the bag when loading the laundry into the washing machine. Avoid all contact of the contaminated laundry with skin or clothing. The laundry can be washed with that of the other household members, using regular laundry detergent. However, if clothing is heavily soiled (e.g. with vomit), it must be cleaned beforehand or washed separately.
• The person’s dishes and utensils must be washed with soap and water after use. A dishwasher can also be used.
• Paper tissues and disposable supplies used by the person must be discarded in a trashcan lined with a bag (ideally with a lid). Tie the bag closed before placing it in the container used for regular waste collection.

Appropriate protective measures for cleaning

• Wear waterproof gloves to protect your hands when cleaning (CDC, 2020b).
• Wash your hands and forearms with soap and water after removing your gloves.
• After cleaning, gloves that are washable should be thoroughly washed with water and detergent and then dried, or discarded and replaced with a new pair if necessary.
• You must wash your hands before and after wearing gloves.
• Remove your clothes and wash them once the cleaning operations are completed.