We have come to learn recently that a type of coronavirus, SARS-CoV-2, causes a disease called Covid-19. It is predominantly transmitted from person to person through respiratory droplets when we talk, sneeze, or cough.

A study published in The Lancet has shown that respiratory swabs of the Covid-19 patients remained positive for SARS-CoV-2 for a mean of 15.4 days. Faecal samples from the same patients were positive for a mean of 27.9 days from the first day of onset of disease, suggesting the significance of personal hygiene in viral transmission.

The virus can also be acquired by touching a contaminated surface. However, SARS-CoV-2 can survive on inorganic surfaces for only a limited time. It can survive for 3 hours in the droplets coughed out in the air but for several hours in unfiltered air, for 24 hours on cardboard, and up to 3 days on plastic and stainless steel.

There is no data to show how long it can survive on fabric and other porous surfaces. To date, there is no vaccine and medication to treat Covid-19, hence the best practice to prevent contracting the virus is to disinfect surroundings and look after personal hygiene.

As they say, control the controllables. While there is very little we can do to decontaminate outdoor areas, for which government authorities are responsible, we can keep household items and ourselves clean. Lots of media advice reaches our ears to suggest how to wash our hands with soap or use Alcohol Based Hand Sanitisers (ABHS) which contain at least 60 percent alcohol.

Why soap? SARS-CoV-2 is an enveloped virus that means its genetic matter is surrounded by a membrane which is made up of lipid (fatty) bi-layer. Washing your hands with soap dissolves this fatty layer and the contents of the virus fall apart. In case soap is inaccessible, hand-sanitisers should be used. Alcohol in ABHS inactivates virus is preferred to soap washes which can cause hands to get dry after several washes a day. Virus particles can become lodged in the cracks of a dry hand and can potentially enter the body if we touch our nose, eyes or mouth with contaminated hand.

How do we disinfect our homes? There are two situations: 1) If there is no Covid-19 patient at home and 2) if there is a diagnosed Covid-19 patient at home. There is not much difference in disinfecting the two, but some extra precautions need taking for the latter scenario.

SARS-Cov-2 is sensitive to several chemicals. The most common of these is sodium hypochlorite which is the active ingredient in household bleach. It normally comes as 5 percent solution of sodium hypochlorite which should be diluted with cold tap water (1 part of bleach mixed with 99 parts of water or simply 2 tablespoons of bleach in 1 litre of water) before use for wiping non-porous surfaces, door handles, knobs, work tops and for mopping floors. For porous surfaces like carpets, soap and warm water is preferable.

If there is a diagnosed patient, or an individual who is suspected to have the virus, the best practice is to isolate them in a separate room. Do not share dishes, glassware, towels, bedding etc.

Bleach decomposes under heat and light. Therefore, it should not be diluted with hot water. It should be prepared fresh or used within 24 hours of preparation. Bleach reacts with other chemicals so it should not be mixed up with other household cleaning solutions.

It should be noted that organic matter on surfaces inactivates bleach so if a surface is soiled with dirt or other organic matter, it should be cleaned prior to wiping with bleach, otherwise it will not be disinfected.

The contact time of surfaces with bleach is also important. One minute with neat (undiluted) and 10 minutes with diluted bleach are the minimum contact times for effective disinfection. Towel used for wiping the surface with bleach or mopping the floor should be clean and soaked in bleach prior to use. Bleach should be used with caution as it irritates mucous membrane, the skin and the airways; use it in ventilated area.

Hydrogen peroxide at 3-6 percent concentration is another chemical used for multipurpose cleaning. It is non-toxic and safe to use for children’s clothes. Contact time of 5 minutes is required with surfaces for disinfection. For mopping floors, equal parts of hydrogen peroxide solution can be mixed with water. Unlike sodium hypochlorite, hydrogen peroxide can be mixed with lemon juice to get scented. (Note: hydrogen peroxide may cause discolouration in wooden floors and marble worktops).

If there is a diagnosed patient, or an individual who is suspected to have the virus, the best practice is to isolate them in a separate room. Do not share dishes, glassware, towels, bedding etc. Do not use the same toilet too, however if a separate toilet is not available then wait for as long as possible after the patient has used it. Disinfect and then use it.

As mentioned above, SARS-CoV-2 lives for much longer in the faeces so unhygienic conditions in bathrooms and unclean hands can potentially transmit the virus. Utensils used by the patient need to be thoroughly washed with dish cleaner and hot water. Detergent will kill the virus in laundry during washing, however, use gloves to carry clothes used by the patient.

This pandemic should be seen as an opportunity to learn some lessons. Huge campaigns to introduce behaviour change have been run through print and electronic media, with great emphasis on social distancing and cleanliness which has induced a considerable behavioural compliance among the people.

Pakistan has a huge burden of infectious diseases, especially hepatitis; 15 million people are infected with hepatitis B and C. Most of the infectious diseases are transmitted from person to person. Successful campaigns like the current one can be run for promoting infection-prevention behaviour in infectious diseases. Such disease control measures will relieve healthcare system of Pakistan.