July 21, 2023

How to Break the Chain of Infection

Overlaid images of a surface being cleaned, PPE and bacteria.

Understanding how to break the chain of infection is vital if you want to safeguard facilities from illness and disease.

Carrying out preventative measures that break the chain of infection is essential for many industries, including healthcare facilities, schools and businesses. It minimises the risk of infection for patients, students, visitors and staff. This results in fewer absences and maintains productivity.

In this blog, we will explain what the chain of infection is and provide examples. Then, we’ll look at how to break the chain at different connections in the link.

What is the Chain of Infection, and Why is it Important?

Germs are all around us. When we come into contact with them, we can become ill and develop a virus.

But before that happens, germs go through a series of events, and are transmitted from one place, or person to another. We call this the Chain of Infection. Each event is represented as a link in the chain, of which there are 6. 

Chain of infection order:

  • Infectious agent – pathogen or germ
  • Reservoir – where a germ will begin to multiply, either on an animal, person, or a surface.
  • Portal of exit – where germs leave the reservoir via an open wound, bodily fluids (sneezing, coughing) or aerosols.
  • Mode of transmission – through direct or indirect contact, ingestion or inhalation.
  • Portal of entry – where the germs will enter a person either through cuts, mucous membranes, or the respiratory tract.
  • Susceptible host – infected person

By taking certain actions, the chain of infection links can be broken at any stage, preventing infection from taking hold.

Infographic of The Chain of Infection
Cleaning and Disinfection

Cleaning and disinfection is a very effective way to reduce the spread of infection and effectively break the chain at numerous points. Proper disinfection can break the chain at the ‘reservoir’ stage, where germs multiply on a surface, and at the ‘mode of transmission’ stage, where there is direct contact.

A two-step cleaning processes must be carried out to ensure bacteria is destroyed.

The first step is to remove dirt, grime and grease from a surface.

The second step is disinfection where microorganisms which carry infection are destroyed. For this step to be truly effective, the disinfectant needs to be left on a wet surface for a specified amount of time. Always follow instructions on the product label for the correct dwell time so that it can work effectively.

There are certain surfaces that numerous people touch regularly throughout the day. These surfaces have lots of bacteria present. We call these ‘hot touch points’. Examples include:

  • Elevator buttons
  • Light switches
  • Doorknobs
  • Desks
  • Keyboards and mice
  • Phones, etc.

The risk of infection is reduced when these areas are disinfected and harmful bacteria is destroyed.

Hand Hygiene



Bacteria found on surfaces is left by people when they sneeze and cough into their hands and then touch a surface. An unsuspecting person who touches the same surface can then easily pick up the bacteria and transfer it when they subconsciously touch their eyes, nose, and mouth. This happens at two stages of the chain following ‘reservoir’-  at ‘mode of transmission’, and ‘portal of entry’.

Practising good hand hygiene breaks the chain at these two points. It is a very effective method of reducing the spread of viruses and prevents up to 20% of respiratory infections. This is because when you wash your hands, you remove harmful bacteria that would otherwise cause infection. To ensure bacteria is properly removed, use soap and water and follow these steps for 20 seconds.

Step-by-step diagram of hand washing technique

With less bacteria on the hands, fewer infectious particles are left on a surface. Additionally, the risk of passing on bacteria through direct contact (e.g. a handshake), during ‘mode of transmission’, is reduced. 


PPE (Personal Protective Equipment) is commonly worn in the healthcare sector to protect from infection. This can include gloves, masks, and eye protection. PPE will break the chain at the ‘portal of exit’, where germs leave the reservoir via bodily fluids, when someone sneezes or coughs.

This is because it creates a barrier which prevents germs from making contact with the hands, nose, mouth, and from entering the airways.

Indoor Air Quality

Viruses are also transported via droplets in the atmosphere. These particles are released into the air when an infected person breathes, speaks, coughs or sneezes. They may then be inhaled at short range, or come into contact with the eyes, nose, or mouth and cause infection. This takes place in the chain at ‘Mode of Transmission’ and ‘portal of entry’.

Improving indoor air quality and introducing ventilation reduces the concentration of respiratory particles, breaking the chain of infection.

This can simply mean opening windows and introducing fresh air in the workplace. For work spaces where there may not be windows or the option to open them, an air filtration unit with a HEPA filter can be implemented. These remove harmful particles from the air and release clean, safe air back into the workspace.

Colour Coded Cleaning

The Colour Coded Cleaning System assigns the colours; red, blue, green, and yellow, to a specific area within your facility. The equipment must are to be used to clean the area they are assigned to and must not be used outside of that area.

If harmful bacteria is present on one surface, particularly where there are bodily fluids, and is transferred to another area, there is a higher risk of people becoming infected. This occurs in the chain of infection at the ‘reservoir’ stage.

Colour coding your cleaning equipment for separate areas prevents cross contamination and reduces the risk of infection.


To wrap up, it’s important to be aware of the chain of infection and how to break it if you want to have the best chance at preventing infection in your facility.

Regular cleaning and disinfection breaks the chain, particularly hand washing. Other measures including the colour coded cleaning system, which avoids cross contamination and the proper use of PPE equipment will effectively break the chain of infection.

For a consultation with one of our specialists, get in touch with us on 01829 773 015

How to Break the Chain of Infection