Module 1 of 3 · 100 minutes
The chain of infection, standard precautions and hand hygiene
By the end of this module you will be able to
- Describe the six links in the chain of infection
- Identify which links care staff can realistically break
- Apply standard precautions to every person, every time
- Perform and justify hand hygiene at the five moments
Work through it
1 interactive for this module, built on the WAJD Teach engine. Nothing moves until you ask it to, and every one has a written version if you would rather read it.
Amara Everybody has done infection control training. Why has it changed so little?
Nadia Because most of it teaches a poster rather than a mechanism. People can recite five moments and still put gloves on at the door and take them off at the sink, which achieves almost nothing.
Amara Start with the mechanism then. The chain of infection.
Nadia Six links. An agent, a reservoir it lives in, a way out, a route to somebody else, a way in, and a person susceptible enough for it to matter. Break one link and there is no infection.
Amara Which link should I be spending my effort on?
Nadia Transmission, overwhelmingly. You cannot change the organism. You cannot make an eighty nine year old with heart failure less susceptible this afternoon. What you can do, forty times a shift, is stop carrying it from one person to the next.
Amara And it is carried on hands.
Nadia Hands and shared equipment. Hoist slings, blood pressure cuffs, glucometers, commodes. The equipment gets forgotten because it is nobody's named job, and a glucometer moving between four people is a very efficient way of moving an organism between four people.
Amara Standard precautions. Explain why they apply to everybody rather than to the people we know are infectious.
Nadia Because you cannot tell by looking, and this is not a technicality. Somebody incubating norovirus is infectious before they feel ill. Somebody colonised with MRSA has no symptoms whatsoever. Blood borne viruses are frequently undiagnosed.
Amara So precautions aimed only at known cases...
Nadia Protect you from the infections you already know about, which are not the ones spreading through your building. The undiagnosed and the incubating are doing the spreading, and by definition they are not on your list.
Amara The five moments. Which one gets missed?
Nadia The fifth. After touching the person's surroundings. Staff who would never skip washing after personal care will adjust a bed rail, move a locker, silence a call bell, and walk straight to the next bed space.
Amara Is touching a bed rail really equivalent to touching the person?
Nadia For this purpose, close enough that the distinction is not worth making. The rail has been touched by the person, by four staff and by two visitors. It is a reservoir, and a reservoir at hand height beside somebody who is unwell.
Amara You said people remember the wrong moments.
Nadia They remember the ones that protect themselves. After body fluids, after touching the person. The ones before, which protect the person from your hands, are the ones that slip. From the chair of the person receiving care, that is precisely backwards.
Amara Gel or soap?
Nadia Gel is for visibly clean hands and it is excellent, faster and kinder to skin than washing. Soap and running water when hands are soiled, after the toilet, and for C. difficile and norovirus.
Amara Why do those two defeat alcohol?
Nadia Different armour. Alcohol works by wrecking a lipid membrane. C. difficile forms a spore with a tough coat and simply sits there. Norovirus has a protein capsid rather than a lipid envelope. Neither is reliably killed, so you stop trying to kill them and physically wash them down the drain instead.
Amara Technique. Twenty seconds is the number everybody quotes.
Nadia Twenty seconds of contact, and then dry properly, which is the half everybody abandons. Wet hands transfer organisms far more readily than dry ones, so a rushed dry undoes a good part of a decent wash.
Amara Where does coverage fail?
Nadia Thumbs, fingertips, backs of hands, between the fingers. Fingertips are the worst of it, because fingertips are what touch people and they get cleaned last and least.
Amara Bare below the elbow. Is that infection control or is it a uniform policy in disguise?
Nadia It is infection control, item by item. A watch strap harbours organisms and stops the skin under it being cleaned. A stoned ring does the same. False and gel nails carry higher bacterial counts and have been implicated in real outbreaks. Long sleeves trail across a wound and then across the next person.
Amara Last one. My hands are cracked and washing them hurts.
Nadia Then report it today, because that is an infection control problem and not a cosmetic one. Damaged skin cannot be decontaminated properly, it harbours organisms in the fissures, and people with sore hands wash less. Emollient, occupational health, and a look at whether the soap is the wrong one.
The written material
The chain of infection
Infection needs six things in sequence: an infectious agent, a reservoir where it lives, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Break any single link and the infection does not happen.
The value of the model is that it tells you where your effort is worth spending. You cannot do much about the agent itself, and you often cannot change how susceptible a frail eighty year old is. What you can break, reliably and repeatedly, is transmission, and the overwhelming majority of transmission in care settings is on hands and on shared equipment.
Standard precautions mean everyone
Standard precautions are applied to every person, in every setting, regardless of what is known about them. That word every carries the whole idea, and it is the part that erodes first.
The reasoning is simple and worth stating plainly: you cannot tell by looking. A person incubating norovirus is infectious before they feel unwell. Someone colonised with MRSA has no symptoms at all. Blood borne viruses are frequently undiagnosed. Precautions applied only to people known to be infectious protect against the infections you already know about, which are not the ones that spread.
There is a dignity argument too. Where precautions apply only to the labelled, the labelled are treated visibly differently, and people notice being handled as a hazard.
- Hand hygiene at the five moments, for everybody
- Personal protective equipment chosen by the task, not by the person
- Safe handling and disposal of sharps and waste
- Decontamination of equipment between people
- Respiratory and cough hygiene
- Safe management of linen and of blood and body fluid spillage
The five moments, and why the order matters
The five moments are before touching a person, before a clean or aseptic procedure, after exposure to body fluids, after touching a person, and after touching their immediate surroundings.
Moments one and two protect the person from your hands. Moments three, four and five protect you, and everybody you touch next, from theirs. People remember the ones that protect themselves and forget the ones that protect the person in front of them, which is exactly backwards from the point of view of the person receiving care.
The fifth moment is the one most commonly missed and the one that most often matters. Touching a bed rail, a call bell or a locker and walking on carries organisms just as effectively as touching the person, and staff who would never skip washing after personal care will move between bed spaces after handling equipment without a thought.
Technique, and the parts everybody misses
Coverage is what makes hand hygiene work, and coverage fails in predictable places: thumbs, fingertips, the backs of the hands, and between the fingers. Fingertips matter most, because they are what touches people, and they are cleaned last and least.
Twenty seconds of contact with soap, then thorough drying. Wet hands transfer organisms far more readily than dry ones, so abandoning the drying halfway undoes a good part of the washing.
Everything below the elbow is part of the technique rather than a dress code: no wrist watches, no rings other than a plain band, no false or gel nails, short natural nails, sleeves above the elbow. Each of these exists because it demonstrably harbours organisms or prevents the skin underneath from being cleaned.
- Twenty seconds of contact, then dry thoroughly
- Thumbs, fingertips, backs of hands and between fingers, deliberately
- Bare below the elbow: no watch, no stoned rings, no false or gel nails
- Cover cuts and grazes with a waterproof dressing before you start
- Report skin damage: cracked hands cannot be decontaminated and hurt to wash
Knowledge check
The knowledge check and your certificate need a free account, so that your progress and results can be saved as evidence.
The learning itself stays free and open. You are reading all of it right now without an account.