One thing is certain, the pandemic has made us aware of the transmission of viruses and in particular to COVID-19. To avoid getting infected, we have collectively adopted a number of simple means that can stop the spread of viruses. To name a few, these include social distancing, wearing masks, washing hands, and isolating those infected.

To express and better understand the different components of virus transmission, health authorities have produced the chain of infection. Here is a representation:

Click to enlarge the image

The elements that make up this chain are:

  1. The infectious agent: the harmful microorganism (bacteria, virus, fungus, parasite) that can be transmitted;
    2. The reservoir: the place where germs (harmful microorganisms) are found;
    3. Portal of exit: where the germs come out;
    4. Mode of transmission: how the germs reach the next sick person (host);
    5. Portal of entry: where germs enter and infect their hosts;
    6. The host: the person whose cell receptors will be infected.

Transmission occurs when each of these elements works with the others. To break the chain, you must break any of these links.


To answer this, let’s look at this aspect from a “human” point of view, how to break the chain to protect people. For the infectious agent, harmful microorganisms, the more we know about them, the more we are able to defend ourselves. This is a more technical aspect for which we let specialists (public health, doctor, specialized organization, etc.) inform us about these germs and how we can better protect ourselves.

For reservoirs, one should be aware that what surrounds us, surfaces, still water, insects, equipment, animals, and other people are all likely to be carriers. To break this link, a professional cleaning, and disinfection program in the home, workplaces, and public places, combined with a prevention policy and pest control will suffice to break it.

For the Portal of exit, think of open wounds, airborne droplets, and bodily fluids (cough, saliva, urine). Coughing into the elbow, hand hygiene, wearing a mask, spill, and waste management are steps that can be taken to break this link.

For the mode of transmission, assume that the disease spreads through direct or indirect contact, ingestion, and inhalation. Again, professional cleaning and a sanitizing program, hand hygiene, and food safety will be enough to break this link.

For Portal of entry, think of open wounds, mucous membranes, invasive tubing (respirator); this link can therefore be broken through hand and personal hygiene, first aid, and the safe removal of catheters and tubing.

For hosts, immunosuppressed people, people with known medical conditions, and those with invasive medical equipment will be more easily infected. The chain is broken with popular education, medical treatment, and immunization campaigns such as vaccination.

Click here to read BREAK THE CHAIN OF INFECTION – Part 2

  • Share this article