Influenza A is one of the most common causes of seasonal flu in the UK and is responsible for many winter outbreaks that place pressure on the NHS, GP services, and the wider health system.
Often simply called flu, influenza A is a viral illness that can cause sudden, intense symptoms and make some people seriously ill, particularly those in higher-risk groups. Understanding how the flu spreads, how to recognise symptoms early, and when to get NHS advice can help protect both you and others.
This guide follows current NHS advice and is designed for families, carers, and anyone wanting clear, trustworthy information about influenza A in the UK.
What Is Influenza A?
Influenza A is a flu virus that infects the nose, throat and lung tissue. It is one of the main types of influenza that circulates each year and is especially common in winter, particularly from autumn onwards.
How influenza A differs from a common cold
While both are viral, flu symptoms usually:
- Come on suddenly
- Are more severe than a common cold
- Cause fever, aches, chills and extreme tiredness
Flu is infectious, easily spread, and can infect large numbers of people quickly during peak flu season.
How Does Flu Spread?
Flu is spread by coughs and sneezes, including when an infected person:
- Coughs or sneezes without covering their mouth
- Touches surfaces after wiping their nose
- Doesn’t follow good hand hygiene
The virus spreads through tiny droplets in the air and on hands and surfaces. Using a tissue when you cough or sneeze, followed by washing hands, significantly reduces the risk of infection.
Flu Symptoms to Watch For
The symptoms of flu usually appear within a few days of exposure and can last a week or more.
Common flu symptoms include:
- A high temperature, fever or chills
- Persistent cough
- Sore throat
- Headache
- Muscle ache and joint pain
- Extreme tiredness
- Loss of appetite
- Runny nose or sneezing
Flu symptoms are more intense than typical flu-like illnesses and may make it difficult to carry out normal daily activities.
Who Is at Greater Risk of Serious Illness?
Influenza A can make some people seriously ill, particularly those with an underlying medical condition.
People at greater risk include:
- Adults with diabetes
- People with kidney disease
- Those with chronic heart or lung conditions
- Pregnant women
- Children aged under 5
- Older adults
- Anyone with a weakened immune system
These groups are prioritised for vaccination through NHS Trust and ICB-led flu programmes.
When to Get NHS Advice
Most people can recover at home, but it’s important to know when to seek help.
Get advice from:
- NHS 111 if symptoms worsen or don’t improve
- Your GP or local pharmacist for symptom relief and medicine
- Local services recommended by your NHS Trust
Call 999 immediately if:
- You have difficulty breathing
- Chest pain develops
- Someone becomes suddenly confused or collapses
In emergencies, the ambulance service or A&E may be needed.
Flu Treatment: What the NHS Recommends
There is no cure for the flu, but treatment focuses on relieving your symptoms or speeding recovery.
NHS-recommended flu treatment includes:
- Rest and fluids
- Paracetamol or ibuprofen for pain and fever
- Staying warm and hydrated
- Avoiding contact with other people while contagious
The NHS does not recommend antibiotics for flu because it is a viral infection. Antibiotics only work against bacterial infections.
The flu will often get better on its own within 7–10 days, although tiredness can last longer.
How to Speed Up Your Recovery
To help you get better sooner:
- Stay at home and avoid contact with others
- Eat light, nutritious meals
- Use tissues and dispose of them safely
- Avoid strenuous activity until fever has gone
Good rest helps reduce inflammation and supports your immune response.
Flu Vaccine and Prevention
Why the flu vaccine matters
The flu vaccine (or flu jab) is the best way to reduce your risk of catching flu and spreading it to others.
The NHS strongly advises eligible people to get the flu vaccine every year, as flu strains change.
You may be eligible if you:
- Are over 65
- Have a long-term condition
- Are pregnant
- Live with someone at higher risk
- Work in health or social care
Being vaccinated against flu significantly reduces the chance of severe illness and hospitalisation.
Can You Catch Flu More Than Once?
Yes. Because influenza viruses change each year, it’s possible to catch flu again in a different season, even if you’ve had it before.
That’s why vaccination is recommended annually.
FAQs About Influenza A
Is influenza A contagious?
Yes. Flu is contagious, especially in the first few days after symptoms start.
How long am I infectious?
Most people are infectious for around 5–7 days, longer in children.
Should I go to work or school?
No. Stay home and avoid contact with others until fever has gone.
Can a pharmacist help?
Yes. A pharmacist can recommend medicines to relieve symptoms.
NHS Leaflet and Further Guidance
Many GP surgeries and NHS Trusts provide a flu leaflet during winter months with local guidance and vaccination information.
Trusted NHS & Authority Sources
NHS England: Flu vaccination programme
https://www.england.nhs.uk/flu/
NHS: Flu overview and treatment
https://www.nhs.uk/conditions/flu/
UK Health Security Agency (UKHSA): Seasonal flu guidance
https://www.gov.uk/government/collections/seasonal-influenza-guidance