Pneumonia, bronchitis or flu – the three deadly threats to people in their 70s

Telegraph

21-02-2025

It's an unfortunate fact that we become more vulnerable to respiratory infections as we get older. Viruses and bugs that we used to be able to clear within days can become a deadly threat and even the Pope isn't immune.
At 88, Pope Francis is in hospital with pneumonia in both lungs (it is more common for both lungs to be affected among the older population), after developing bronchitis and a polymicrobial infection.
'The bronchitis was probably caused by a common virus – anything from the common cold to influenza or Covid – that's caused inflammation of the lining of the blood vessels,' explains Dr David Strain, an associate professor at the University of Exeter Medical School who specialises in viral infections.
'Polymicrobial infection means that all the bugs that are supposed to be living in the respiratory tract are starting to replicate more than they should,' he says. Then, one of those bugs will have become dominant, causing the immune system to send a whole load of inflammatory white blood cells to the area. 'As soon as our inflammatory cells start to fill up the airways, that's where we say it's pneumonia,' Dr Strain says.
How to know which one you've got
The symptoms of the flu, bronchitis and pneumonia overlap but flu typically starts with a sudden fever, body aches and exhaustion.
Bronchitis occurs as a result of a respiratory infection, such as the flu, and a hacking cough that brings up mucus is a telltale sign.
Pneumonia usually causes breathing difficulties, chest pain and a high temperature.
An older person's symptoms at each stage – an initial flu infection, the subsequent bronchitis and later pneumonia – will depend on their overall health and biological age (how old your cells and tissues appear). If an elderly person is aware that they are ill, it's usually a good sign, Dr Strain says. 'The people who are really, really sick have no concept of how unwell they are because their body is focusing entirely on fixing the infection.'
Elderly patients with pneumonia often have delirium and can appear severely demented for a few days, as their brain has effectively switched itself off so all their energy can be diverted, Dr Strain explains.
'We see that with people with pneumonia all the time, that older patients don't complain or think that there is a problem because their body is trying to health itself and ignoring the basic senses. They actually start to feel worse as they get better.'
What is the flu?
Influenza is very infectious and can spread rapidly between people. It's caught by breathing in air containing the virus (such as after a person coughs or sneezes) or touching a surface where the virus has landed and then touching the mouth or nose.
Flu breaks down the protective lining of the airways, which is made up of mucus and hair and usually acts like a Compeed plaster or a shield, Dr Strain says.
While a young, healthy person with a strong immune system should be able to repair this lining and completely recover within days, it can develop into a serious illness for older people. For them, flu and other respiratory viruses act as sandpaper, scraping away the protective layer that lines the airways.
'We all get exactly the same virus but it's the amount of protective layer and amount of reserve that you've got available,' he explains.
'A young, fit person will only need 10 per cent of their reserve to fight the flu virus, whereas an older adult might need 100 per cent. The body throws absolutely everything at the virus and there's nothing left for the next thing that comes along.'
What is bronchitis?
'Bronchitis means that the lining of the airways is inflamed and irritated,' Dr Strain explains. ' Bronchus is the airways [the tube that carries air from your windpipe into your lungs] and itis means inflammation.'
It's the body's response to flu but can also be caused by other respiratory viruses.
'If a young, healthy person develops bronchitis, the protective layer in their respiratory tract will very quickly heal over,' Dr Strain says. 'For older adults, it takes them much, much longer for the protective layers to heal over.'
In the meantime, they are vulnerable to a bacterial infection, which occurs if the normal bugs living in the airways penetrate through the damaged mucus lining. This can ultimately lead to pneumonia.
What is pneumonia?
Pneumonia is inflammation of the lungs, usually caused by an infection.
When the body senses that inflammation has occurred (for example, as a result of bronchitis) and bacteria is present, the immune system releases white blood cells, also known as leukocytes, whose job it is to ward off infection and inflammation, Dr Strain explains.
'But these cells can clog up the alveoli – tiny air sacs in the lungs that allow oxygen and carbon dioxide to be exchanged – so that we can't breathe properly,' he adds.
In England, emergency admissions for pneumonia range between 130,000 to 270,000 per year and it is fatal in 5-14 per cent of hospitalised cases.
'The vast majority of people who are dying from pneumonia are already in their last two years of life,' Dr Strain explains. For patients with lots of health problems, it's usually the thing that pushes them over the edge, he adds. Flu and pneumonia were responsible for more than 24,000 deaths (or 4.2 per cent of all deaths in England and Wales) in 2023.
How to treat them at home
An influenza infection will cause flu-like symptoms, including a sudden high temperature, an aching body and exhaustion. At this stage, turn to simple paracetamol and drink plenty of fluids to manage symptoms, Dr Strain says. Antibiotics don't work against it.
'Having a fever burns lots of extra energy, so bringing a fever down with paracetamol will actually help people to get better quicker,' he explains.
Similarly, bronchitis usually clears up on its own within weeks by drinking lots of fluid, getting plenty of rest and taking paracetamol to ease symptoms. 'You don't need to be in hospital if you can continue to drink fluids and still feel lucid,' Dr Strain says.
If a patient has pneumonia, they are usually given antibiotics and get better at home within two to four weeks, though older and at-risk patients will likely be admitted to hospital.
When to see a doctor
'As soon as a person starts behaving differently – it could be that they become erratic, hyper-emotional or completely withdrawn – that's the time we need to see them in hospital,' Dr Strain says.
'Even if they are still at the viral [flu] stage, we need to make sure they're not at risk of a bacterial infection. It's a bacterial infection, on top of their viral infection, that's going to do damage,' he says. Doctors can find out if a bacterial infection has occurred through a quick blood test.
If the infection is viral, then the patient will be given fluids and paracetamol, just as they would at home, but if there's any evidence of a bacterial infection, there will be heavy-duty antibiotics for 24 to 48 hours, Dr Strain says. 'Getting on top of that as quickly as possible is really beneficial for patients,' he says.
How to prevent flu, bronchitis and pneumonia
Avoiding catching flu or another respiratory infection in the first place is the key step.
While infections can be unavoidable, sensible steps like avoiding people who've got a viral illness – including telling family to delay a visit if they've got a cough and cold – is simple but effective, Dr Strain says. The flu vaccine means a flu infection is more likely to be mild.
It's also important to prevent frailty by keeping active, Dr Strain says. 'Frailty – the inability to tackle infections as they hit you – is what's going to put you in hospital,' he says.
'Going out for your daily five minute walk to pick up the newspaper, or even just getting out a few times a week, is very clearly demonstrated to boost your immune system,' Dr Strain notes.
For those who keep active, they will still feel terrible when hit with a respiratory infection, but they're going to bounce back from it quickly, he says.
The more frail a person is, the longer it will take to recover from pneumonia, he notes. 'It can take several months to build your strength back up to where you were and it's important for those picking up their loved one from hospital to know that they're not going to be as strong as they were.'
'At the end of the day, we cannot make people live forever,' says Dr Strain. 'What we want to do is keep them as healthy as possible until they die. And pneumonia is the thing that tends to be the final straw for people who have problems with their health.'