News story
24 June 2026
Three subtypes of severe pneumonia have been identified in Cambridge – a crucial step in tailoring future treatment
Responsible for an estimated 2.5 million deaths per year, it’s the most common infectious cause of death worldwide. But now – thanks to Cambridge research, part-funded by ACT’s supporters – there’s been a potentially life-saving leap in understanding of both pneumonia and its future treatment.
Researchers have shown that severe pneumonia has three different subtypes, which helps explain why some patients in intensive care units (ICUs) recover faster than others, while for some the disease can be life-threatening. These findings are hoped to inform tailored treatments, allowing individual patients to receive the most appropriate therapies.
Paul White, ACT’s Director of Communications and Impact, has thanked the charity’s supporters, reminding them that success doesn’t always have to follow on the back of large investments. “It’s often assumed that progress comes from major investments in expensive equipment or projects,” he says, “but this study is a powerful reminder that this isn’t always the case. Sometimes just small amounts of money invested in a particular product, service or study can make a huge difference to patients’ lives.
“In this case, the donation from our supporters has helped facilitate this groundbreaking research – which has the potential to save lives and will change how severe pneumonia is treated in patients moving forward. I would like to thank all our supporters who continue to help us change patients’ lives. In this case, as with many others, they have played a part in something that will have a lasting impact for patients and their families well into the future.”
Doctors have long struggled to understand why patients whose condition looks similar clinically can have very different recoveries. Some respond quickly to treatment, while others remain critically ill for weeks or even die.
Dr Andrew Conway Morris from the Department of Medicine at the University of Cambridge and an ICU consultant at Addenbrooke’s Hospital said: “Even though we’re able to treat the initial infection, many patients with severe pneumonia still struggle to come off the ventilator and can develop lung failure. Therapies to tackle inflammation in the lungs have had mixed results in clinical trials – some suggest they are beneficial, others that they’re harmful.
“It’s often assumed that progress comes from major investments in expensive equipment or projects, but this study is a powerful reminder that this isn’t always the case.”
“The current approach of classifying patients by their clinical syndromes – sepsis, acute respiratory distress syndrome and so on – without looking at the underlying biology risks missing what’s key. Instead of asking ‘Does this patient have pneumonia?’, we should be asking ‘What’s the inflammatory pattern in this patient’s lungs?’”
In findings published today in Nature Communications, Professor Conway Morris and team recruited patients admitted with suspected severe pneumonia to the ICU at Addenbrooke’s. Severe pneumonia is usually diagnosed through a combination of symptoms, imaging and blood tests. Symptoms typically include fever or hypothermia, low oxygen levels, breathing difficulties and confusion.
Instead of relying only on blood tests or scans, however, the Cambridge team analysed immune cells, inflammatory signals, and gene activity in fluid taken from patients’ lungs. They discovered that there are three distinct biological types – or ‘pneumotypes’ – of severe pneumonia, none of which could be reliably detected using standard blood tests, even though they were strongly linked to how patients recovered.
Dr Mark Jeffrey from the Department of Medicine at the University of Cambridge, the study’s first author, explains: “Even though on the surface, all of the patients seemed to have similar types of pneumonia, with comparable illness severity, oxygen levels and clinical diagnoses, their outcomes were very different.
“It was only when we drilled down and looked at patterns of inflammation that the differences became apparent. Severe pneumonia is not a single disease, but several biologically distinct conditions that happen to look alike. This helps explain why ‘one-size-fits-all’ treatments – including some immune-modulating drugs – have often failed in clinical trials.”
The tests used to determine the pneumotypes are too complex to enable rapid classification, but the researchers hope to develop a simplified tool that could help them stratify the patients and ultimately offer tailored treatments.
Dr Vilas Navapurkar from the John Farman Intensive Care Unit at Addenbrooke’s Hospital adds: “If we know which subtype of pneumonia an individual has, we can potentially tailor their treatment more precisely, boosting the immune response in some, while calming harmful inflammation in others. This has the potential to help critically ill patients, reduce deaths from pneumonia, shorten ICU stays and cut unnecessary antibiotic use.”
The study was funded by ACT, the National Institute for Health and Care Research Cambridge Biomedical Research Centre, and The Forster Foundation. Professor Conway Morris is a Fellow at Emmanuel College, Cambridge.
ACT is the official charity for Addenbrooke’s and funds cutting-edge equipment, specialist staff, extra comforts and vital research above and beyond what the NHS is able to provide and is raising money to help build both the Cambridge Cancer Research Hospital and the Cambridge Children’s Hospital.
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