Lower respiratory tract infections (LRTIs) remain a common cause of respiratory mortality, responsible annually for approximately 40 000 deaths in the UK and 2.7 million globally.1 The most severe common LRTI in the UK is community-acquired pneumonia (CAP), which for hospitalised patients has a mortality of 8%2 and the incidence of which is increasing as the population ages.3 Despite being the only common bacterial cause of LRTIs for which we have an effective vaccine, Streptococcus pneumoniae still remains the dominant bacterial cause of LRTIs, responsible for 16% of fatal cases globally4 and 40% of hospitalised CAP in the UK.2 The manuscript published in this edition of Thorax by Lansbury et al.5 provides additional data that further underlines the challenges in trying to reduce the persisting high morbidity and mortality caused by S. pneumoniae.

Lansbury et al 5 present data from 5186 patients with CAP admitted to two Nottingham hospitals between 2013 and 2023, of which 2193 (42%) were caused by S. pneumoniae. The study has several advantages, including (1) its size and duration allowing the assessment of changes over time, (2) being based at research sites with a long pedigree of CAP research and (3) using the Bioplex-24 urinary antigen test to diagnose S. pneumoniae CAP and identify the causative capsular serotype. S. pneumoniae is surrounded by a capsule that consists of repeating chains of usually three or four monosaccharide units, with different chemical compositions resulting in over a 100 different capsular serotypes. All existing S. pneumoniae vaccines are based on capsular antigens and only protect against the serotypes contained in the vaccine; hence …