Winter Bugs and Sick Notes: Flu, Norovirus and When You Can Go Back to Work

Official UK advice does not give one rule for every infection. The table below summarises the main guidance from the NHS, UKHSA and the Food Standards Agency. Your employer’s own sickness policy may add extra requirements.

In most cases, no. Under the UK’s self-certification rules, you can tell your employer you were ill for the first 7 calendar days, including weekends, without a doctor’s note. A fit note is normally needed from day 8 onwards. Most winter infections pass well within a week, which is why a sick note is the exception rather than the rule.

A few points are worth knowing:

• Statutory Sick Pay now starts on day one. From 6 April 2026, SSP is payable from the first qualifying day of sickness and the Lower Earnings Limit was removed. The weekly rate is the lower of £123.25 or 80% of your normal weekly earnings. Check GOV.UK for the current rules.
• Company sick pay can be different. Your contract or staff handbook may ask for a doctor’s note sooner than 7 days, or for a specific form of evidence. Check it before you decide.
• Some jobs have their own rules. Food handlers and healthcare staff have exclusion periods (see below).
• You may need a note for another reason, such as a long recovery, complications, or an employer that asks for proof.

For a full explanation of fit notes, read our guides to GP sick notes, fit notes and sick note myths.

Flu is different from a cold. It usually comes on within a few hours and affects your whole body, while a cold appears gradually and mainly affects your nose and throat. Typical flu symptoms include a sudden high temperature, aching body, tiredness, a dry cough and a sore throat.

How long are you off with flu? Most healthy adults recover at home within about a week, although a cough and tiredness can last longer. The NHS advises resting, keeping warm, drinking plenty of fluids and taking paracetamol or ibuprofen for aches and temperature.

When can you go back to work after flu? The NHS advises trying to stay at home if you have a high temperature, feel hot or shivery, or do not feel well enough to do your normal activities. You are more likely to pass flu on in the first 5 days. A sensible rule of thumb many GPs suggest is to wait until your temperature has been normal, without paracetamol or ibuprofen, for at least a day, and you feel able to cope with your normal day. A lingering cough alone does not always mean you must stay off.

Do antibiotics help? No. Flu is caused by a virus, and antibiotics do not treat viral infections. If a sore throat or sinus symptoms continue, our guides to sore throat and tonsillitis and sinusitis explain when to get checked.

Norovirus is a highly contagious stomach bug that causes vomiting, diarrhoea, stomach pain, and sometimes a high temperature and headache. Symptoms usually start 12 to 48 hours after infection, can come on suddenly, and usually last 12 to 60 hours.

When can you go back to work after norovirus? The NHS and UKHSA advice is to stay off work, school and nursery until 48 hours after your last symptom. You can still pass the virus on for up to two days after you feel better. Avoid visiting hospitals and care homes for the same period.

• Wash your hands with soap and water. Alcohol hand gel does not kill norovirus.
• Do not prepare food for others until you have been symptom-free for 48 hours.
• Drink plenty of fluids in small sips if you feel sick, and rest.
• Clean surfaces with a bleach-based product.
• Do not visit your GP surgery or hospital while you have symptoms, as you could spread the infection. Phone or video consultations are a safer option.

Most people recover without treatment. Seek advice if symptoms last longer than about 60 hours, you cannot keep fluids down, you show signs of dehydration, or you have a long-term health condition.

UKHSA guidance for adults with symptoms of a respiratory infection, including Covid-19, is to try to stay at home and avoid contact with other people if you have a high temperature or do not feel well enough to go to work or do your normal activities. You can return once you no longer have a high temperature and feel well enough. If you test positive for Covid-19, adults are advised to try to stay at home for 5 days after the day of the test, and to avoid people at higher risk of serious illness for 10 days where possible. This advice is guidance, not a legal requirement.

If you have to leave home while unwell, wear a face covering, avoid crowded places and keep away from people with weakened immune systems.

If you handle food or work in healthcare, social care or a nursery, the rules are stricter because infections can spread to vulnerable people.

• Food handlers with diarrhoea or vomiting must stay away from food handling until they have been symptom-free for 48 hours, according to Food Standards Agency guidance. If you take anti-diarrhoea medication, the 48 hours is counted after you stop it.
• You should tell your employer about your symptoms before you return.
• For some confirmed infections, environmental health or your employer may set a different exclusion period or ask for clearance.

Read the Food Standards Agency guidance on food handlers’ fitness to work and follow your workplace policy.

If you are too unwell to queue at a surgery, or you do not want to spread an infection in a waiting room, you can speak to a GP online. At The GP Clinic, doctors are GMC-registered and NHS-trained, appointments run from 9am to 9pm, 365 days a year, and a Sick (Fit) Note for Work costs £45, with same-day service.

1. Book your consultation and choose a time that suits you.
2. Verify your identity through a quick online check or by showing photo ID at the start of the call.
3. Speak to the GP by video. Describe your symptoms, when they started and how they affect your ability to work.
4. Receive your note by email if the doctor can clinically support it. Online notes are intended for short absences. If you need longer off work, the doctor may advise you to see your own NHS GP.
5. Send it to your employer and check whether your sick pay policy needs any other paperwork.

You need to be aged 18 or over and physically in the UK at the time of the appointment. Online GPs cannot help with emergencies or symptoms that need an in-person examination. Read how doctor’s notes work in the UK for more detail.

You do not need to feel completely back to normal, but you should be well enough to do your job safely and no longer infectious under the guidance above. Many people find it helps to return gradually after flu or a long bout of illness.

• Talk to your employer about a phased return, shorter days or lighter duties for a few days.
• Ask for adjustments if you are still tired, such as working from home for a short period, if your role allows it.
• Ask your doctor about a “may be fit for work” fit note if you could do some duties with support. A fit note can suggest a phased return, altered hours, amended duties or workplace adaptations.
• Get a fitness-to-return letter if your employer asks for confirmation that you are fit to come back. Our Employee Fitness to Work Medical (£45) is designed for this.

Most flu, norovirus and colds can be managed at home. Get medical advice from NHS 111 or a GP if:

• You are aged 65 or over, pregnant, or have a long-term condition or weakened immune system.
• Your flu symptoms have not improved after 7 days.
• You cannot keep fluids down, or you have signs of dehydration such as dark urine, a dry mouth or dizziness.
• Diarrhoea and vomiting last longer than about 60 hours.

Call 999 or go to A&E if you have sudden chest pain, difficulty breathing, or you start coughing up blood. This service is not for emergencies.

• Get your flu vaccine if you are eligible. The NHS offers it each autumn and early winter to people at higher risk, and the best time is before flu starts spreading. See the NHS flu vaccine page.
• Wash your hands often with soap and warm water, especially after using the toilet and before eating or preparing food.
• Cough or sneeze into a tissue and bin it straight away.
• Stay home when you are infectious. Going to work while ill can spread infection and delay your own recovery.

Winter illnesses are common, and most pass within days. Stay at home while you are infectious, follow the 48-hour rule for stomach bugs, and use the self-certification rules before you worry about a sick note. If your employer needs a doctor’s note, or you are not sure you are well enough to return, you can speak to a GP without leaving home. Book an online GP appointment or request a sick note for work.

This article is for general information and is not a substitute for medical advice. In a medical emergency, call 999 or NHS 111. This service is not for emergencies.