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What is Pneumonia?

What is Pneumonia?

If you have pneumonia it means you have a type of chest infection where one or both of your lungs have been affected. With pneumonia the lung tissue becomes infected, which makes the air sacs (alveoli) in the lungs fill up with fluid. When this happens, you will usually find it harder to breathe.
Pneumonia tends to be more serious than bronchitis – another main type of chest infection. Unlike pneumonia, bronchitis is an infection of tubes in the lungs called bronchi, though both conditions often have similar symptoms. It’s even possible to have both types of chest infection at the same time (this is called bronchopneumonia).
Every year in the UK around eight in 1,000 adults are affected by pneumonia (i), most often during the autumn and winter months. The reason pneumonia is more likely to affect you in the autumn and winter is because many of the respiratory viral infections that can cause it – including viruses that cause colds and flu – spread more easily from one person to another and are more common at these times of year.
Thankfully, if you develop a mild case of pneumonia there’s a very good chance you’ll recover fully, with experts suggesting fewer than one in 100 people die of pneumonia that’s mild enough to be treated at home (ii).
If your condition is more severe and you need hospital treatment, the outlook is a little less encouraging, with five to 10 people out of every 100 admitted to an ordinary hospital ward with pneumonia failing to recover (it’s thought most of these are people who were elderly or who had another health condition before developing pneumonia) (ii).
Even more seriously, around 30 per cent of people with pneumonia who need intensive care die as a result of having the condition (iii).

Pneumonia risk factors

Pneumonia can affect anyone of any age, but it’s more common and has a higher risk of being more severe in some groups than others, including:

  • Babies and young children

  • People aged 65 and older

  • People with heart, lung, brain, liver or kidney disease

  • People with diabetes 

  • People with asthma 

  • People with COPD 

  • People with cystic fibrosis

  • People with cancer who are having chemotherapy treatment

  • People with a weakened immune system (those with HIV, for example, or people taking immune-suppressing medication after an organ transplant)

  • People who smoke 

  • People who drink alcohol to excess or use recreational drugs

Types of pneumonia

You’ll often hear pneumonia called community-acquired pneumonia or hospital-acquired pneumonia. This is simply a way of describing where you caught the infection.
Community-acquired pneumonia   If you were infected outside of a hospital or long-term care facility, you’re said to have community-acquired pneumonia. According to the British Lung Foundation, community-acquired pneumonia is much less contagious than flu or a cold, which means if you have it you’re unlikely to give the disease to someone else (iv).
Hospital-acquired pneumonia   On the other hand if you developed pneumonia while in hospital, your condition is described as hospital-acquired pneumonia. If you’re in hospital and have been put on a ventilator, if you have a tracheostomy tube helping you to breath, or if your immune system is weak as a result of having another disease or treatment, you are susceptible to catching hospital-acquired pneumonia.
Different types of pneumonia are also named after what has caused them – for instance bacteria, a virus or fungi. Most causes of pneumonia happen when someone breathes in one of these substances and they multiply, causing a lung infection. Very rarely, however, pneumonia can develop from an infection that started somewhere else in the body.
Experts believe there are more than 30 different causes of pneumonia (v), most of which belong to the following categories:
Bacterial pneumonia   Most causes of community-acquired pneumonia in adults are caused by a bacterial infection, with many different types of bacteria capable of causing the condition. Some of the bacteria that commonly cause pneumonia include:

  • Streptococcus pneumoniae

  • Haemophilus influenzae 

  • Chlamydophilia pneumoniae

  • Legionella pneumophilia

A much milder form of bacterial pneumonia is sometimes called atypical pneumonia, caused by the bacterium Mycoplasma pneumoniae (this is also called mycoplasma pneumonia).
Viral pneumonia     Viruses such as cold and flu viruses, coronaviruses, measles, chickenpox can all cause viral pneumonia, which experts believe is responsible for around a third of all pneumonia cases (v). If you have viral pneumonia you’re also more likely to develop bacterial pneumonia.
Fungal pneumonia    This type of pneumonia is caused by fungi, however it’s rare in the UK. It’s more likely to affect people with a weakened immune system (iv) or people with certain jobs who are at risk of breathing in fungal spores from soil or bird droppings (farmers, gardeners and builders, for instance).
Aspiration pneumonia    If you develop pneumonia as a result of inhaling food, drink, vomit, saliva, foreign objects, smoke or chemical particles or certain fumes into your lungs, the condition is called aspiration pneumonia. This can happen, for instance, if you have problems with swallowing or if you’ve been sedated by medicines, alcohol or other drugs.
Pneumonia and COVID-19       One of the viruses that can cause pneumonia is the SARS-CoV-2 coronavirus that triggers the symptoms of COVID-19. That’s because COVID-19 affects the lungs in some people, filling them with fluid. This causes coughing and breathlessness, as well as other symptoms.
Experts believe while most people recover from pneumonia without any lasting damage to their lungs, pneumonia caused by COVID-19 can be more severe and cause lung damage that could cause breathing difficulties for months (vi).
Not all variants of the virus, however, are thought to cause pneumonia. Some experts believe for most people the omicron variant may not enter so deeply into the lungs as some other variants. That suggests that while it may still cause coughing it’s less likely to result in breathing difficulties (vii).

What are the symptoms of Pneumonia?

If you’re infected with pneumonia you may develop symptoms quite quickly – often within one or two days – though sometimes the condition can progress more gradually, with symptoms appearing after several days (viii).
The symptoms you’re most likely to experience include one or more of the following:

  • Coughing (the cough may be dry or it may produce thick mucus that’s green, yellow, brown or blood stained)

  • Breathing difficulties, including breathlessness (even when resting), rapid breathing or shallow breathing

  • Chest pain

  • Increased heart rate 

  • Fever

  • Sweating and shivering

  • Poor appetite

  • A feeling of general unwellness

Other, less common, symptoms include:

  • Headache 

  • Wheezing

  • Fatigue

  • Nausea

  • Vomiting

  • Sore muscles and joints

  • Confusion and disorientation (usually in older people)

The different types of pneumonia all have some similar symptoms. However if you have bacterial pneumonia you may have a mucus cough accompanied by chest pain, shortness of breath, fever and fatigue, while viral pneumonia tends to trigger a drier cough – especially in the early stages – along with fever, chills, headache, muscle pain, tiredness and weakness.
The symptoms of viral pneumonia are, in fact, often similar to those of the flu, which can make diagnosis more difficult. But while a cough may often be dry during the early stage of viral pneumonia, it often progresses to a more productive, or chesty, cough – which is less likely if you have flu.

When to see a doctor

If you have the symptoms of pneumonia it’s important to get medical advice, since you may need treatment with antibiotics to clear a bacterial infection, even if it’s a mild one. Contact your GP or use the 111 online service. If you can’t get the help you need online, or you need help for a child under the age of five years, call 111.
If, however, you or someone you’re looking after is experiencing any of the following, call 999 for an ambulance:

  • Struggling to breathe

  • Coughing up blood 

  • Blue face or lips

  • Feeling cold and sweaty with pale or blotchy skin 

  • Collapsing or fainting

  • A rash that does not fade when you roll a glass over it

  • Confusion or extreme drowsiness

  • Infrequent urination (or no urination)

It’s also advisable to see a GP if your symptoms don’t improve within three days of taking antibiotics; if your cough has lasted longer than three or four weeks; if symptoms such as fever, wheezing or headache become worse or severe; if you’ve been having repeated chest infections; or if you have any other symptoms you’re worried about.

How to treat pneumonia

The treatment you’ll need and where you get it will depend on how mild or severe your pneumonia symptoms are.

Mild pneumonia

This is usually treated with prescription antibiotics at home. People aged 65 or younger who have no other severe medical conditions and whose symptoms aren’t thought to pose a risk are most likely to have mild pneumonia.
You may also take painkillers such as paracetamol to help relieve pain and lower your temperature. These may be particularly helpful if your condition has been caused by a virus, as you won’t be prescribed antibiotics because they’re only effective against bacterial infections.

Moderate pneumonia

If your pneumonia is moderate you may experience worsening shortness of breath along with low blood pressure, [ADD LINK] drowsiness and confusion. If you are older, you have an underlying medical condition or you are generally in poor health you’re much more likely to have moderate pneumonia rather than a mild case. This is usually treated at a hospital where you may need more than one type of antibiotic treatment if your infection has been caused by bacteria.

Severe pneumonia

Severe pneumonia usually means that your heart, kidneys or circulatory system are at risk of failing, or that your lungs cannot take in enough oxygen. People with severe pneumonia are usually admitted to an intensive care unit where they may receive antibiotics via a drip along with other medicines. They may also need oxygen through a mask or via tubes in their nose if their oxygen levels are low, while very severe cases may need to be placed on a ventilator to help with breathing.
How long you’ll take to recover depends on how severe your symptoms are. However they should begin to improve soon after you start having treatment. The NHS offers the following general guide to how your recovery should progress (ix):

  • After one week your temperature should have returned to normal

  • After four weeks your chest pain and mucus production should be much lower

  • After six weeks your cough should have substantially improved and you shouldn’t feel so breathless

  • After three months your symptoms should mostly have gone, though you may still feel very tired

  • After six months you should feel back to normal


Complications of pneumonia

According to the NHS, young children, older people and people with pre-existing health conditions are more likely than others to experience complications of pneumonia. Some of these complications include:

  • Fluid on the lungs or pleural effusion (according to the British Lung Foundation around one in 10 people with pneumonia develop this, and they often need a longer course of antibiotics as a result (x))

  • Sepsis (also known as septicaemia this is when an infection gets into your blood; it happens rarely as a complication of pneumonia but  it can be very serious as it can lead to organ failure)

  • Lung abscesses (also rare, these can form inside or around your lung and may have to be surgically drained – you’re more likely to develop a lung abscess with pneumonia if you have a history of alcohol misuse or you have a serious pre-existing illness)

  • Pleurisy (this causes inflammation of the thin linings between your lungs and ribcage and can cause chest pain and even respiratory failure)


How to prevent pneumonia

It may not always be possible to prevent pneumonia but there are some things you can do that might help reduce your risk of developing it.
Keep your hands clean   While most cases of community-acquired pneumonia are caused by bacteria and rarely pass from person to person, viral pneumonia and the viruses that cause it are often contagious, which means it can spread easily. This is why it’s important to practice good hygiene, especially during the autumn and winter months when cold and flu viruses are more widespread than at other times of the year.
Keeping your hands as clean as possible can help reduce the spread of these viruses, but also remember to carry tissues and use them whenever you cough or sneeze, then throw the tissue away as soon as possible (wash your hands again after handling a used tissue).
Quit smoking   According to the British Lung Foundation, smokers have an increased risk of developing pneumonia and other chest infections, as do children of parents who smoke (xi). For information about giving up smoking, including details of stop smoking products to help with nicotine withdrawal (including patches, lozenges and gum), take a look at our Stop Smoking guide. 
Drink alcohol in moderation   Experts also suggest drinking an excessive amount of alcohol weakens the immune system, which could make you more susceptible to infections like pneumonia (viii). Try to stick to the government’s alcohol intake guidelines, which say you should aim to have no more than 14 units of alcohol a week (there’s more on cutting back on alcohol as well as examples of how many units of alcohol are found in popular drinks in our guide to alcohol misuse)
Get your jabs   If your risk of getting pneumonia is higher than average, you may want to consider getting an annual flu jab, since many cases of pneumonia are caused by flu (most people who fall into this category should already be getting regular free annual jabs). Some people are also eligible for a pneumonia vaccine on the NHS, including babies, adults aged 65 or older and children and adults with certain long-term health conditions that increase their risk of developing pneumonia. Babies are offered two doses of this jab – one at 12 weeks and one at one year of age – but adults only need to have it once (that is, it’s not an annual jab like the flu vaccine). Invitation for this vaccine – which protects against the bacterial form of pneumonia – should be automatic, but if you think you’re eligible and you haven’t been offered it, speak to your GP.
Stay active   Regular physical activity – anything that makes you sweat a little and breathe harder – can help keep your lungs healthy and arguably less susceptible to infection. Aim to do at least 150 minutes of moderate activity each week (the easiest way to carve this up is to do half an hour of exercise five times a week). If you have a lung problem such as asthma that makes exercising more difficult during the colder months, try activities that you can do indoors rather than work out in the cold outdoor air.
Stay warm   Wrapping up warm when you’re outside in the winter and keeping your house heated could help reduce your risk of getting chest infections, especially if you’re aged 65 or older, if you have an existing medical condition or if you aren’t very mobile. Try to make sure the rooms you regularly use in your home are heated to at least 18C, and consider wearing several thinner layers rather than one thick layer of clothing (don’t forget to also wear a hat, scarf and gloves when you’re out and about).
Eat as healthily as you can   Having a healthy, balanced diet with at least five portions of fruit and vegetables a day is important if you want to keep your resistance to infections as strong as possible. Find out more about foods that may help strengthen your immune system and natural supplements that provide immune system support
It may also be a good idea to take a good-quality multivitamin and mineral supplement, especially if your diet isn’t as healthy as it should be all of the time. This can help make sure you get the main nutrients your immune system needs when you haven’t had time to eat properly, for instance.
Other supplements you may want to try include high-strength fish oils for their omega-3 content. Omega-3 fatty acids – most notably EPA and DHA, which are found in oily fish such as salmon, trout, sardines and mackerel – are widely considered helpful for general health and wellbeing, including regulating the immune system (xii). There is even some limited evidence that omega-3s may help protect against the development of bacterial pneumonia – though studies so far have only been carried out in animals, which means there’s no guarantee the findings would be the same in humans. (xiii).
If you’re a vegetarian or vegan, you can now get these beneficial omega-3 fats too by taking supplements containing marine algae rather than fish.
Meanwhile vitamin D is also widely thought to regulate the immune system, with low levels linked with a greater susceptibility to infection (xiv). One study even suggests having a low vitamin D level may increase your risk for developing pneumonia (xv).
Indeed the UK government suggests everyone should consider taking a daily vitamin D supplement at least during the autumn and winter months when sunshine is in short supply (xvi). Try a vitamin D3 supplement, as this is the natural form of the vitamin that your body makes when it’s exposed to sunlight (vitamin D3 drops as well as veggie-friendly supplements are also now available).

Recovering from pneumonia

Meanwhile if you’ve been diagnosed with mild pneumonia and are treating yourself at home, it’s a good idea to drink plenty of fluids to avoid dehydration and get as much rest as possible to help your body recover. Once you start feeling a bit better, try not to rush back to your usual routine – it can take weeks or even months to recover from pneumonia fully, so try not to do too much too soon.
While you’re recovering the British Lung Foundation also recommends exercising your lungs by taking long, slow, deep breaths, or blowing through a straw into a glass of water (deep breathing, it says, is good for clearing mucous from your lungs) (xvii). Your GP may also be able to recommend a few breathing exercises that may be useful, or read about breathing exercises in an online leaflet published by the Association of Chartered Physiotherapists in Respiratory Care.
Even a mild case of pneumonia can knock you off your feet, but these days the infections that cause it are mostly easily treated. Knowing what you can do to take care of yourself and even help keep pneumonia at bay can be very useful, including taking supplements that may help keep your immune system working efficiently. If you want to read up about a wide range of other infectious illnesses (and lots more besides), take a wander around our pharmacy health library


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(xii) Gutierrez S, Svahn SL, Johansson ME. Effects of Omega-3 Fatty Acids on Immune Cells. Int J Mol Sci. 2019 Oct; 20(20): 5028. Available online:
(xiii) Hinojosa CA et al. omega-3 Fatty Acids Protect Against Pneumococcal Pneumonia. Am J of Res and Cr Care Med 2017; 195:A6855. Available online:
(xiv) Hewisom. M. Vitamin D and immune function: an overview. Proc Nutr Soc. (2012 Feb).;71(1):50-6. Available online:
(xv) Holter. JC, Ueland .T, et al. Vitamin D Status and Long-Term Mortality in Community-Acquired Pneumonia: Secondary Data Analysis from a Prospective Cohort. PLosOne. Jul 1 2016;11(7).
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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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