Pneumonia: Symptoms, Causes and How Long Recovery Takes

TSBy Tayyab Sarwar14 September 2026Other InfectionsSymptoms & DiagnosisRecovery

Pneumonia is an infection that inflames the tiny air sacs in the lungs, which then fill with fluid or pus. It can be mild enough that someone keeps working through it or serious enough to need intensive care. In the UK it is one of the most common reasons for emergency hospital admission, particularly in winter and particularly among older adults. Much of the confusion around it comes from the gap between those two extremes and from how long recovery takes even after the infection has cleared.

What causes pneumonia

Most pneumonia in the UK is caused by bacteria, with Streptococcus pneumoniae, often called pneumococcus, the most common single cause. Viruses cause a large share too, including flu, RSV and COVID-19. A viral infection can pave the way for a bacterial pneumonia on top of it. Less commonly, pneumonia is caused by organisms such as mycoplasma, which tends to produce a milder illness in younger people, or by inhaling food, drink or vomit, called aspiration pneumonia.

Community-acquired pneumonia is the term for pneumonia caught in everyday life, while hospital-acquired pneumonia develops during a hospital stay and is often caused by different, harder-to-treat bacteria.

Symptoms

The typical symptoms are a cough, which may bring up yellow, green or blood-stained mucus, a high temperature, breathlessness, rapid breathing and chest pain that is often sharp and worse when breathing in or coughing. People also commonly feel exhausted, lose their appetite, sweat and shiver and feel generally very unwell.

Older adults are the important exception. They may have few chest symptoms and no fever. Instead they become confused, fall, stop eating or simply seem much less well than usual. A sudden change in an older person during winter should always raise the possibility of a chest infection. Our guide to illness risk in older adults covers why presentation changes with age.

Chest infection, bronchitis or pneumonia?

The terms overlap in everyday use. Acute bronchitis affects the larger airways, usually follows a cold, is almost always viral and causes a cough that can last three weeks but rarely makes people seriously unwell. Pneumonia affects the air sacs deeper in the lung, is more often bacterial and more often causes fever, breathlessness and feeling properly ill. A clinician will usually distinguish them by examination, breathing rate, oxygen levels and sometimes a chest X-ray. The distinction matters because bronchitis rarely needs antibiotics while pneumonia usually does. A lingering cough alone is covered in why a cough will not go away.

Who is most at risk

Pneumonia can affect anyone, but it is more common and more dangerous in babies and young children, adults over 65, people who smoke, people with long-term lung conditions such as COPD or asthma, people with heart, kidney or liver disease or diabetes and anyone with a weakened immune system. Difficulty swallowing after a stroke or with conditions such as Parkinson's disease increases the risk of aspiration pneumonia.

How it is treated

Most people with pneumonia are treated at home with a course of antibiotics, typically for five days, plus rest, fluids and paracetamol or ibuprofen for fever and pain. Clinicians use simple scoring tools that consider confusion, breathing rate, blood pressure and age to decide who can safely stay at home. If you are prescribed antibiotics, you should begin to feel better within about three days. If you do not, or if you get worse, contact your GP or NHS 111 again.

Hospital treatment is needed when oxygen levels are low, breathing is very fast, blood pressure is low, the person is confused or the illness is severe. In hospital, treatment may include intravenous antibiotics, fluids and oxygen. Pneumonia is a common cause of sepsis, so rapid deterioration needs emergency care.

Cough medicines are not recommended. The cough helps clear the lungs. Warm drinks, honey and sitting upright tend to be more useful for comfort.

A realistic recovery timeline

Recovery takes longer than most people expect. Knowing that avoids needless worry. A widely used NHS timeline for community-acquired pneumonia is:

After one week, fever should have settled
After four weeks, chest pain and mucus production should have substantially reduced
After six weeks, cough and breathlessness should have substantially reduced
After three months, most symptoms should have resolved, though tiredness may remain
After six months, most people feel back to normal

Older adults and people with other conditions may take longer. Returning to work or exercise gradually is sensible. Our guide to returning to exercise after a respiratory infection offers a step-by-step approach that applies well here. A follow-up chest X-ray is sometimes arranged around six weeks later for smokers and people over 50 to check the lung has cleared.

Prevention

The pneumococcal vaccine protects against the most common bacterial cause and is offered as a single dose at 65, earlier for some people with long-term conditions and routinely to babies. The annual flu vaccine matters too, because flu is a frequent trigger for pneumonia. COVID-19 and RSV vaccines reduce other viral routes in for eligible groups. All of these are covered in every winter vaccine in the UK and who is eligible. Stopping smoking is one of the most effective single steps, since smoking damages the lung's natural defences. The NHS pneumonia pages have more detail.

When to get help

See a GP or call NHS 111 if you have a cough with fever and breathlessness, chest pain when breathing, a cough that is getting worse rather than better, or if you are in a higher-risk group and develop chest symptoms. Call 999 or go to A&E for severe breathlessness, blue or grey lips or skin, confusion, drowsiness, coughing up significant amounts of blood or chest pain that is severe or crushing.

A quick recap

Pneumonia is an infection of the air sacs in the lungs, most often bacterial but frequently following a virus. Typical symptoms are cough, fever, breathlessness and sharp chest pain, while older adults may simply become confused or unwell. Most people are treated at home with antibiotics and should improve within three days. Recovery takes weeks to months, with tiredness often the last symptom to go. Pneumococcal and flu vaccination plus not smoking reduce the risk.

Frequently asked questions

Is pneumonia contagious?

The germs that cause it can spread through coughs and sneezes, but most people exposed do not develop pneumonia. Whether they do depends largely on age and health.

How long does pneumonia last?

Fever usually settles within a week of treatment, but cough can last six weeks and tiredness can last three to six months.

Can you have pneumonia without a fever?

Yes, particularly in older adults, who may instead become confused, fall or stop eating.

What is walking pneumonia?

An informal term for a mild pneumonia, often caused by mycoplasma, where people feel unwell but are able to carry on with daily life.

Do you always need antibiotics for pneumonia?

Bacterial pneumonia needs antibiotics. Purely viral pneumonia does not respond to them, though antibiotics are often given because it can be hard to rule out bacteria.