Sep 28, 2020
The process of Covid-19 transmission made simple

By Anthony Mugo

You may have wondered why the Ministry of Health and other agencies are emphasising four main preventive actions as being the most important in protecting us from getting infected by the coronavirus. These are: wearing masks properly while out in public; frequently washing with soap or using a sanitiser with at least 60 percent alcohol; social distancing; and avoiding crowded places. I have attempted a simplified explanation of the science behind the recommendation in this post.

1. Wearing masks

Face masks work by preventing particles larger than a certain size from passing through them. The common saying: “Your mask protects me, and my mask protects you” captures the essence of how masks work. When someone breathes out, they produce air together with water vapour in the form of varying sizes of droplets. The smallest of these, which are smaller than 5 micrometres (one micron is one-millionth of a meter), known as aerosols, can float in the air for hours. Larger ones stay afloat for shorter periods before falling onto various surfaces. More droplets are produced and projected further when people talk loudly, sneeze, cough or sing. Masks work by reducing the amount of droplets ejected by someone coughing or sneezing and also preventing the wearer from breathing infected droplets hanging in the air. For them to be effective, they must always fully cover the mouth and the nose.

2. Washing hands with soap

Experts emphasise that there is a distinct difference between washing hands with water alone and washing hands with soap. Soap contains substances known as surfactants which lift germs from the skin. At the same time, people tend to scrub their hands more thoroughly when they use soap hence ensuring that all germs get washed away. The coronavirus is made of genetic materials covered with a layer of fat. Soap dissolves the fat and exposes the virus, making it incapable of infecting other people.

3. Social distancing

As noted above, many droplets fly out of the mouth and nose when someone sneezes or coughs. Scientists have determined that this distance can be up to two meters. Therefore, social distancing is a very important preventive measure. The chances of breathing infected droplets reduce significantly the further apart people are and are virtually eliminated when people can maintain 1.5 to 2 meters space, hence the emphasis on social distancing.

4. Avoiding crowded places

Places where crowds gather should be avoided during a pandemic such as Covid-19 whose causative agent, the coronavirus, is transmitted through respiratory droplets. It has been noted that crowded indoor spaces are particularly dangerous, especially when such places are poorly ventilated. In such places, the possibility of infection is a factor of two things. The length of stay and the quality of the air.

The longer people stay in crowded indoor spaces that are poorly ventilated, the higher the likeliness that they will get infected by the coronavirus. It takes a certain number of viral particles for infection to be established. Therefore, authorities and health experts discourage large gatherings in closed spaces such as churches, classrooms, and entertainment halls.

When you think about it, protecting yourself against the coronavirus is not expensive. However, it demands discipline and consistency in adhering to recommended protective protocols. When infection occurs and progresses to Covid-19 disease, much more resources are required to provide care and treatment and unfortunately these sometimes fail, and lives are lost. The age-old truism about staying free of disease is still true today: Prevention is better than cure.