What is it about?

Lower respiratory infections, such as pneumonia and bronchiolitis, are the world's leading infectious cause of death. As part of the Global Burden of Disease Study 2023, we estimated how many people fall ill and die from these infections in 204 countries between 1990 and 2023, and which of 26 microbes are responsible, including 11 never modelled before. In 2023 these infections caused about 2.5 million deaths. Young children and adults over 70 were hit hardest. Deaths among children under five fell by a third since 2010, but sub-Saharan Africa remains far from the global target. Streptococcus pneumoniae was the leading cause (634,000 deaths), followed by Staphylococcus aureus and Klebsiella pneumoniae; newly modelled pathogens such as non-tuberculous mycobacteria and Aspergillus emerged as important killers.

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Why is it important?

These estimates show both the success of vaccination and how much remains to be done, especially for older adults, where little progress has been made, and in countries with the highest child mortality. By attributing deaths to specific bacteria, viruses and fungi, the study helps prioritize vaccines, diagnostics and antibiotics - and highlights the growing role of pathogens often linked to antimicrobial resistance.

Perspectives

Being part of the GBD Lower Respiratory Infections and Antimicrobial Resistance collaboration is a privilege. Behind each number there are millions of preventable deaths, many in children and the elderly. I find it particularly striking that S. aureus and Klebsiella, pathogens we fight every day in hospitals, rank so high globally.

Professor Stefano Di Bella
Universita degli Studi di Trieste

Read the Original

This page is a summary of: Global burden of lower respiratory infections and aetiologies, 1990–2023: a systematic analysis for the Global Burden of Disease Study 2023, The Lancet Infectious Diseases, December 2025, Elsevier,
DOI: 10.1016/s1473-3099(25)00689-9.
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