Chest Infection or Just a Cough? How Long It Lasts and When to Worry

Every winter, coughs and chest infections fill GP waiting rooms across George. Most of them are not dangerous, most of them are not bacterial, and most of them get better on their own with time. Yet a chest infection is one of the most common reasons people ask for antibiotics they usually do not need, and at the same time one of the conditions where a small number of people are genuinely unwell and should be seen quickly.

This article explains the difference between an ordinary chest cold and something more serious, how long a cough should realistically last, why antibiotics are so often the wrong answer, and the warning signs that mean you should see a doctor or go to casualty. It also covers something that matters a great deal in South Africa specifically: when a cough that will not go away should make you think about tuberculosis. This is general information, not a substitute for a consultation. If you are worried about your own cough or your child's, that is a good reason to come and see us.

Chest cold, bronchitis, or pneumonia?

These words get used loosely, so it helps to know what they actually mean.

What most people call a chest cold, and what doctors call acute bronchitis, is inflammation of the larger airways. The main feature is a cough, with or without phlegm, and it is a diagnosis made once more serious causes have been ruled out. It is almost always viral, and it almost always settles by itself.

Pneumonia is an infection that reaches the lung tissue itself, and it is more serious. The features that point towards pneumonia rather than a simple chest infection are a fast heart rate, fast breathing, a temperature above 38 degrees, and abnormal sounds your doctor hears when listening to your chest. In an otherwise healthy adult under 70, pneumonia is unlikely when none of these is present. When one or more is present, it needs proper assessment, usually including a chest X-ray. This is exactly the kind of judgement a consultation exists to make, and it is why "it is just a chest infection" is a conclusion to reach with a doctor, not an assumption to make at home.

One common myth is worth clearing up: the colour of your phlegm does not tell you whether you need antibiotics. Green or yellow phlegm comes from the inflammatory cells and shed lining of the airways, not from bacteria. Discoloured phlegm on its own is not a sign of bacterial infection and not a reason for antibiotics.

How long should a cough last?

This is the question that drives most unnecessary antibiotic requests, because people expect a cough to clear in a few days and worry when it does not. The reality is slower than most people think.

The cough from a chest infection typically lasts two to three weeks, and can persist for up to eight weeks as the airways recover. A large 2024 study of patients with lower respiratory tract infections found the average cough lasted just over sixteen days. A cough that is slowly improving over two or three weeks is doing exactly what it should, and antibiotics will not speed it up in any way that matters.

After a viral infection, the airways can stay irritated and over-sensitive for weeks, which is why a dry, nagging cough can linger long after you otherwise feel well. This post-viral cough is common, it is self-limiting, and up to eight weeks is within the normal range.

There is, however, an important South African exception to all of this, and it is the next section.

When a lingering cough means you should be tested for TB

South Africa has one of the highest tuberculosis burdens in the world. In this setting, a cough that will not go away is not simply a stubborn cold. It is a reason to be tested for TB.

The rule worth remembering is straightforward: a cough lasting more than two weeks should prompt a TB test, especially if you are living with HIV, have had TB before, or have been in close contact with someone who has TB. For anyone, a cough lasting more than three weeks should be investigated for TB regardless of other symptoms. The test is simple, usually a sputum sample, and it is one of the most important things a GP can arrange.

Certain features should prompt TB testing or urgent review whatever the duration of the cough:

• Coughing up blood, even a small amount
• Drenching night sweats
• Unintentional weight loss
• A fever that persists
• Ongoing tiredness and loss of appetite

None of these should be ignored or waited out. TB is curable, and the earlier it is found the better the outcome, for you and for the people around you. If your cough has lasted more than two weeks, please come in for a test rather than assuming it is a leftover cold. People living with HIV are at particular risk and can have less typical symptoms, which is one reason regular care matters; you can read more in our guide to long-term health with HIV.

Why antibiotics usually will not help

It feels logical that a chest infection needs an antibiotic. The evidence says otherwise for most people, and understanding why helps you avoid a treatment that carries real downsides for no real benefit.

More than nine in ten otherwise healthy adults with an acute cough have a viral infection. Antibiotics do nothing against viruses. Even when bacteria are detected, they are often simply living in the airways without causing the illness, and there is no practical test in a GP consultation that reliably separates a bacterial chest infection from a viral one.

A Cochrane review, which pools the best available trials, found that antibiotics for acute bronchitis in otherwise healthy people shortened illness by about half a day over an eight to ten day period. Half a day is not a meaningful gain, and it comes at a cost. Antibiotics commonly cause nausea, diarrhoea, and rashes, occasionally cause serious allergic reactions, and disturb the normal bacteria in your gut. Every unnecessary course also adds to antibiotic resistance, which is the slow erosion of these medicines' power to work when they are genuinely needed, for you or for someone else later.

For most chest infections, the honest answer to "what should I do" is rest, fluids, and time, while keeping an eye out for the warning signs below. That is not the practice being unhelpful or withholding treatment. It is the treatment, and it is what the evidence supports. When antibiotics are genuinely needed, and sometimes they are, we will say so clearly. You can read more about why this matters in our article on antibiotic resistance and superbugs.

Who is at higher risk

Most healthy adults and children weather a chest infection without trouble. Some people are more vulnerable to complications and should have a lower threshold for being seen early:

• Adults over 65
• People with chronic lung disease, including asthma and COPD
• People with chronic heart disease
• People with diabetes
• People living with HIV
• People who have had TB before, or who currently have it
• Anyone whose immune system is suppressed, including by chemotherapy or long-term steroids

If you are in one of these groups and you develop a chest infection, it is reasonable to be checked sooner rather than waiting the usual two or three weeks. The same infection that is a nuisance for a healthy 30-year-old can be more serious for someone with COPD, diabetes, or HIV. If you manage a chronic condition with us, this is exactly the situation where a quick review is worthwhile. Telehealth often works well for an initial assessment; more on that below.

When to see a GP, and when to go to casualty

Read this part carefully. Most chest infections are safe to manage at home, but a few people are seriously ill, and knowing the difference matters.

Go to casualty or call an ambulance immediately if you or your child have any of the following:

• Severe breathlessness, or being unable to speak in full sentences
• Lips, face, or fingertips turning blue or grey
• New confusion, drowsiness, or being difficult to wake
• Breathing that is very fast or laboured, or a child visibly struggling to breathe and sucking in at the ribs or neck
• Chest pain with breathlessness
• Coughing up a significant amount of blood

Do not wait for an online booking in these situations, and do not drive yourself if you are severely breathless. Our emergency contacts page lists the numbers to keep on hand.

See a GP soon, within a day or two, if you are not in immediate danger but you notice:

• A fever that lasts more than three or four days, or one that returns after you seemed to be improving
• Becoming breathless on mild activity, like walking across a room
• Chest pain that is sharp and worse when you breathe or cough
• Any blood in your phlegm
• Symptoms that get worse again after an initial improvement
• A cough that has lasted more than two weeks (for TB testing, as above)
• A chronic condition, such as COPD, diabetes, or HIV, with new chest symptoms

These are the situations where being seen changes the outcome. Catching pneumonia or TB early, rather than waiting it out, is the whole point.

Preventing chest infections: flu and pneumococcal vaccines

Two vaccines reduce the burden of winter chest infections and their complications. They are not the same, they protect against different things, and their funding under South African medical schemes differs, so it is worth understanding both.

The flu vaccine lowers your risk of influenza and the complications that can follow it, including pneumonia, and the benefit is greatest for higher-risk groups. Most major South African medical schemes fund one flu vaccine per beneficiary per year from a preventive or screening benefit, often without touching your savings, but the exact rules and who qualifies vary by scheme and by your risk status. The honest position is that it is widely covered, but you should confirm with your own plan. We offer the seasonal flu vaccine at the practice to everyone, billed to the preventive benefit on most medical schemes, or at a cash price of R200 for private patients without medical aid. There is more detail in our 2026 flu guide.

The pneumococcal vaccine protects against pneumococcus, a leading cause of pneumonia and of serious invasive infection. The evidence for it is strong against invasive pneumococcal disease and more variable against pneumonia overall, which is worth being honest about. South African guidance recommends it routinely for adults aged 65 and over, and for younger adults with chronic conditions such as chronic lung disease, heart disease, or diabetes, and for people living with HIV, usually given as one conjugate vaccine followed later by a polysaccharide one. Medical-scheme cover for the pneumococcal vaccine is generally narrower than for flu, typically limited to members aged 65 and over or those under 65 with qualifying chronic or high-risk conditions. If you are in one of those groups, it is worth asking us whether you are due, and checking your eligibility with your scheme.

Keeping current with both vaccines, where you qualify, is one of the few things that genuinely reduces how often and how badly you get chest infections. Vaccination is also covered more fully in our 2026 vaccines guide.

A winter chest infection is, for most people, an unpleasant few weeks that resolves on its own. Rest, fluids, patience, and an eye on the warning signs are what most coughs need. The two situations to take seriously are a cough that lasts beyond two weeks, which in South Africa means a TB test, and the emergency signs that mean someone is genuinely unwell. If anything here matches what you or your family are going through, come and see us.