As the clocks change and indoor life takes over, colds and flu start moving through offices, schools and Tube carriages. This article sets out the simple habits the NHS recommends to slow that spread, how to do them properly, and how much difference the research suggests they make.
How do colds and flu actually spread?
According to the NHS, both colds and flu are spread by germs from coughs and sneezes. The NHS says these germs can survive on hands and surfaces for about 24 hours, which is why a handrail, a door handle or a shared keyboard can matter as much as the person sitting next to you.
Timing matters too. The NHS says you can pass on a cold from a few days before symptoms start until they have all gone, which usually takes 1 to 2 weeks. For flu, it says you are most likely to pass it on in the first 5 days after infection. In practice, that means people often spread an infection before they know they have one, so no single habit can stop it entirely.
How should you wash your hands?
The NHS describes an 11-step method, and it is worth knowing in outline:
- Wet your hands with water.
- Apply enough soap to coat them.
- Rub your palms together.
- Rub the back of each hand with the opposite palm, cleaning between the fingers.
- Rub your palms together again, cleaning between the fingers.
- Interlock your fingers and rub your fingertips against the opposite palms.
- Rub each thumb with the opposite hand.
- Rub your fingertips on the opposite palm, on both hands.
- Rinse under water.
- Dry completely with a disposable towel.
- Use the towel to turn off the tap.
The NHS says the whole process should take about 20 seconds, roughly the time to sing “Happy Birthday” twice, and suggests removing rings and bracelets first if possible. The US Centers for Disease Control and Prevention (CDC) gives a similar figure, advising scrubbing for at least 20 seconds. The NHS advice on colds and flu specifically mentions warm water and soap.
When does hand washing matter most?
Washing after every touch of a surface is neither realistic nor necessary. The NHS lists these moments:
- after using the toilet or changing a nappy
- before and after handling raw foods such as meat and vegetables
- before eating or handling food
- after blowing your nose, sneezing or coughing
- before and after treating a cut or wound
- after touching animals, their food or their cages
The CDC adds a few more, including before and after caring for someone who is sick at home with vomiting or diarrhoea, and after touching rubbish. For respiratory infections, the “after blowing your nose, sneezing or coughing” moment, plus before eating, is a sensible pair to build into your day.
Do hand sanitisers work as well as soap?
The NHS says that if soap and water are not immediately available, you can use an alcohol-based hand sanitiser if you have one. The CDC says to look for a product with at least 60% alcohol, to check the label, and to use it only when soap and water are not readily available. It describes washing with soap and water as the best way to get rid of germs in most situations.
So sanitiser is a useful back-up for a commute or a meeting room, not a replacement for the sink. If you are using a gel, the Cochrane evidence discussed below notes that skin irritation was reported in some trials, so moisturising afterwards is reasonable if your hands become sore.
What should you do with coughs, sneezes and tissues, and when should you stay home?
The NHS advice on tissues is straightforward. Cover your mouth and nose with a tissue when you cough or sneeze. If you do not have one, cough or sneeze into the bend of your elbow rather than your hands. Throw used tissues away as soon as possible and then wash your hands.
The NHS also advises against sharing towels or household items such as cups and children’s toys while someone has a cold. In a shared flat or family home, giving the person with a cold their own towel and mug is a low-effort change.
Both NHS pages say to stay at home if you have a high temperature or feel too unwell for your normal activities. For flu, the NHS also says to avoid other people if you feel hot, cold or shivery.
This is the habit that is hardest to follow, particularly when work or caring responsibilities make absence difficult. It is also, logically, the one that cuts exposure most directly, because it removes you from the places where germs pass between people. If you have a role where staying off is not possible, careful hand washing and tissue use matter all the more.
What does the evidence say these habits achieve?
A Cochrane systematic review of physical measures against respiratory viruses, last updated in 2023, looked at randomised trials of hand hygiene programmes. Cochrane’s summary says hand hygiene programmes may help to slow the spread of respiratory viruses. The results were as follows:
| Outcome | Relative reduction | Certainty |
|---|---|---|
| Acute respiratory infections (9 trials, 52,105 participants) | 14% | Moderate |
| Combined acute respiratory infection, influenza-like illness or influenza (19 trials, 71,210 participants) | 11% | Low |
| Influenza-like illness alone (11 trials) | No clear difference | Low |
| Laboratory-confirmed influenza (8 trials) | No clear difference | Low |
Illustrative arithmetic helps make the first figure concrete. Cochrane describes it as around 380 events per 1,000 people falling to 327 per 1,000. A 14% reduction applied to 380 gives 380 × 0.86 ≈ 327, so the two figures agree. That is roughly 53 fewer episodes per 1,000 people over the study periods, not a guarantee for any individual.
Two cautions follow. First, the benefit is modest: hand hygiene reduces the chance of illness but does not remove it. Second, the authors note that adherence to the programmes was often low, which limits firm conclusions, and the separate flu results did not show a clear difference. The honest reading is that hand hygiene probably helps a little with respiratory illness in general, and the evidence for flu specifically is less certain.
Can anything else reduce your risk?
Hygiene habits sit alongside, rather than instead of, other protections. Vaccination is the main one for flu, and our guide to who is eligible for the autumn flu vaccine explains the timing. Everyday health foundations also count, including sleep and a warm, healthy home.
The NHS says there is little evidence that vitamin C, echinacea or garlic help with colds, so it is better to put your effort into habits with at least some trial support. To make washing automatic, attach it to something you already do, such as arriving home or before lunch, an approach explored in our article on building a habit that sticks.
When should you speak to a GP or NHS 111?
Most colds and flu clear up with rest and fluids. The NHS advises seeing a GP about a cold if:
- a high temperature lasts more than 3 days
- symptoms get worse, or your temperature is very high
- you feel short of breath or have chest pain
- symptoms have not improved after 10 days
- you have had a cough for more than 3 weeks
- you have a long-term condition or a weakened immune system
- you are worried about your child’s symptoms
For flu, the NHS says to get an urgent GP appointment or use NHS 111 if you are worried about a baby’s or child’s symptoms, are 65 or over, are pregnant or have recently given birth, have a long-term condition or weakened immune system, feel very unwell or short of breath, or your symptoms have not improved after 7 days.
Call 999 or go to A&E if you get sudden chest pain, have severe difficulty breathing (such as gasping, choking or being unable to speak in full sentences), or cough up blood. The NHS says not to drive yourself there.
Small habits, modest but real gains
Washing hands for 20 seconds at the right moments, using tissues, keeping your own towel when you are ill and staying home when you are properly unwell will not make anyone immune to winter bugs. The best trial evidence suggests a modest reduction in respiratory illness, with more uncertainty about flu itself. Because the habits cost almost nothing and carry little risk, they remain worth keeping up, alongside vaccination where you are eligible.
This article is general information, not a substitute for advice from a doctor or other qualified health professional. If you are unwell or worried about your symptoms, speak to your GP or call NHS 111.
Sources: NHS; Centers for Disease Control and Prevention; Cochrane
