Disinfection and cleaning during COVID-19

The main way COVID-19 spreads is through droplet transmission. When an infected person sneezes or coughs without covering their nose and mouth, droplets fall on surrounding surfaces. These droplets carry the SARS-CoV-2 virus, and can remain on various surfaces for a long time. (Read more: How long can SARS-CoV-2 virus survive on different surfaces?) 

If these surfaces are not disinfected regularly, other people coming in contact with the same surfaces might also contract the COVID-19 infection. This is the reason why regular and proper disinfection of frequently used surfaces is very important. These surfaces can be everything from doorknobs, handles, switches to furniture, electronics, etc. Even fruits and vegetables can become carriers of COVID-19 infection if they’re not washed and cleaned properly.

Read more: How to wash fruits and vegetables during the COVID-19 pandemic

You might assume that cleaning and disinfecting are one and the same things, but they’re really not. According to the US Center for Disease Control and Prevention, these two processes indicate the following.

• Cleaning: This refers to the removal of dirt, impurities and germs from a surface. Cleaning does not essentially kill germs, but by removing them it reduces their number and therefore reduces the risk of infections.
• Disinfection: This refers to the use of approved chemicals to kill germs on a surface. Disinfecting does not clean a surface, but does kill the germs on it and therefore reduces the risk of infections. 

Routine cleaning and disinfection practices help in removing the pathogens involved in the spread of the disease or considerably reduce the load on regularly used or contaminated surfaces. The most effective method is to clean a surface and then disinfect it. This way the removal of dirt and impurities as well as the killing of germs are all ensured.

Read more: 32 most frequently asked questions about COVID-19

Washing your hands with soap and water thoroughly and regularly for at least 20 seconds does clean the hands properly. This is a basic hand hygiene practice that everyone should follow, since it accomplishes the act of cleaning. However, in medical settings or to particularly reduce COVID-19 infection, disinfecting the hands might be necessary. For this purpose, the WHO recommends two other chemical, alcohol-based disinfectants.

• Disinfectant I: 80% ethanol, 1.45% glycerine, 0.125% hydrogen peroxide
• Disinfectant II: 75% isopropanol, 1.45% glycerine, 0.125% hydrogen peroxide

The efficacy of both these disinfectants against the SARS-CoV-2 virus was recently tested by an international research team headed by Prof. Stephanie Pfander from the Department of Molecular and Medical Virology at Ruhr-Universitat Bochum. The study, which was published in Emerging Infectious Diseases on 13 April 2020, revealed that 30 seconds after applying the above-mentioned disinfectants, the SARS-CoV-2 virus is made inactive. 

The study also insists that apart from the exact formulation provided by the WHO, it’s the presence of ethanol and isopropyl at those precise percentages that makes these disinfectants so effective. So, if you’re buying a hand sanitizer or making one at home, keep these proportions in mind.

Read more: How to make hand sanitizer at home

When it comes to disinfecting surfaces, the most effective chemical ingredient is sodium hypochlorite. This chemical comes in the form of a white powder which is dissolved in water for common use. These solutions of sodium hypochlorite are referred to as bleach, which often also consists of some percentages of other compounds like chlorine, sodium hydroxide and calcium hypochlorite.

While this might be the form in which sodium hypochlorite solution is found in all households, the MoHFW (in a recent telemedicine video in conjunction with the All India Institute of Medical Sciences or AIIMS) recommends the following solutions to disinfect surfaces to prevent the transmission of the SARS-CoV-2 virus:

• Sodium hypochlorite liquid bleach with 3-5% chlorine content: Add 1 part of bleach solution to 2.5 parts of water
• Sodium hypochlorite liquid bleach with 5% chlorine content: Add 1 part of bleach solution to 4 parts of water
• Sodium hypochlorite liquid with 10% chlorine content: Add 1 part of bleach solution to 9 parts of water
• Bleaching powder with 70% chlorine content: 7 grams of powder in 1-litre water

Apart from these, the MoHFW also recommends the use of phenolic compounds to clean and disinfect surfaces like floors. The regular household phenyl, for example, which is a white concentrated liquid, is an easily accessible phenolic substance which can be used as a disinfectant for floors. 

A solution commonly referred to as quaternary ammonium compound is also used as a floor and surface disinfectant in healthcare facilities, along with MoHFW-approved chlorine solutions like chloroxylenol (4.5-5.5%) and benzalkonium chloride - which can safely be used at home as well.

The following are some of the most common surfaces which need to be both cleaned and disinfected regularly to reduce the risk of COVID-19. The cleaning and disinfecting recommendations mentioned below are approved by the MoHFW and the US CDC.

• Floors: All indoor floor areas such as entrance lobbies, rooms, corridors and staircases, escalators, elevators, security guard booths, office rooms, meeting rooms, cafeteria should be mopped with a disinfectant with 1% sodium hypochlorite or phenolic disinfectants.
• High-contact surfaces: Surfaces such elevator buttons, handrails/handles and call buttons, escalator handrails, public counters, intercom systems, equipment like telephone, printers/scanners, and other office machines should be cleaned twice daily by mopping with a linen/absorbable cloth soaked in 1% sodium hypochlorite. Frequently touched areas like table tops, chair handles, pens, file covers, mouse pad, tea/coffee dispensing machines etc. should specially be cleaned.
• Metallic surfaces: Metallic surfaces like door handles, security locks, keys etc. should be wiped down regularly with 70% alcohol if and when the use of bleach is not suitable.
• Soft surfaces: Surfaces like sofas covers, carpets, rugs and curtains or drapes should be properly laundered using hot water and a detergent containing colour-safe bleach. According to the CDC, you can also use household disinfectants which have sodium hypochlorite, hydrogen peroxide, quaternary ammonium, ethanol or isopropyl as active agents.
• Electronic surfaces: It’s important to regularly clean televisions, computers, laptops, tablets, phones, keyboards, mouse, touch screens and remote controls by following the manufacturer’s instructions only. If these instructions are not provided by the manufacturer, you can use alcohol-based wipes or sprays to disinfect these electronic equipment. However, make sure you wipe these down and dry them properly before use.
• Laundry: Use warm water and detergents to clean clothes, sheets, towels and other such items. While it’s best not to use harsh chemicals on laundry items, you should wash them separately - especially if they belong to a sick person - and dry them out completely before use.

Read more: Can coronavirus spread through clothes and shoes?

While cleaning and disinfecting all surfaces is very important to keep COVID-19 as well as other viral infections, bacterial infections and fungal infections at bay, it’s equally necessary to remember that safety precautions must be taken while disinfecting. Depending on your skin sensitivity and the strength of the chemical compounds being used, disinfection is a job that should be done with the utmost care.

The following are some of the most important do’s and don’ts everyone should keep in mind while disinfecting homes, offices, etc.

• Always wear gloves, a mask and covered shoes while using strong disinfectants or bleach. Make sure you also keep your eyes safe from these compounds.
• Read labels carefully and take every precaution if you’re making your own disinfectant at home.
• Never mix ammonia with a bleach solution because that can cause a toxic gas called chloramine  to be created. This gas can lead to severe health issues like shortness of breath and chest pain.
• While buying sodium hypochlorite 1%, make sure the compound is recently made and not old. This can reduce its potency as a disinfectant.
• According to the WHO, hypochlorite becomes ineffective in the presence of organic material like viruses. Therefore, it is important to first clean the surfaces with soap and water or detergent before proceeding to use the disinfectant.
• Do not use disinfectant sprays on potentially high-contamination areas like the bathroom and toilet bowl. Spraying and using water jets can create splashes that can increase the spread of the virus.
• Always start cleaning and disinfecting from cleaner areas and gradually more towards the dirtier and dirtiest areas, i.e. do the bathrooms last because it’s a natural waste disposal area. 
• Avoid cross contamination by properly and separately disposing of cleaning equipment like cloth, mops, gloves, etc. Do not mix this waste with other household wastes. Wear a new pair of gloves to fasten the bag and throw it away.
• Disinfect all cleaning equipment after use and before reusing it in another area of the house or office.
• Disinfect buckets by soaking in bleach solution or rinse in hot water.

Contrary to the practice being followed by civic and municipal authorities around the world, the WHO has advised against the spraying of disinfectants in indoor as well as outdoor settings.

Spraying or fogging of environmental surfaces is not recommended, as a study has shown that spraying as the main strategy for disinfecting is ineffective in removing contamination outside of direct spray zones. It can also be a risk to the eyes of the public and cause other respiratory or skin irritations. Adverse health effects are linked with the use of disinfectants, especially for the workers in such facilities where these methods have been used. If at all disinfectants are to be used, they should be applied with the use of cloths or wipes soaked in disinfectant.

The WHO also doesn't recommend spraying or fumigating outdoor spaces such as streets and marketplaces as disinfectant is inactivated when it comes in contact with dirt and debris, while manually cleaning every spot in outdoor spaces is also not possible. The spraying of chemicals cannot cover all surfaces for the duration it is needed to be on to kill or inactivate viruses or other pathogens. To add to that, common surfaces like the neighbourhood streets or pavements haven't emerged as major reservoirs of infection either.