[en] [en] OBJECTIVES: Invasive pneumococcal disease (IPD) remains a significant global health threat. Although pneumococcal conjugate vaccines have considerably reduced the burden of IPD after their implementation, changes in serotype distribution do occur. This study examines the epidemiology of serotype 4 IPD in Belgium from 2007 to 2024, focusing on a recent and pronounced increase in cases. The aim is to identify and characterize high-risk populations.
METHODS: Epidemiologic data from the passive laboratory-based IPD surveillance, as conducted by the national reference center for invasive pneumococci at UZ Leuven, were used to study the evolution of serotype 4 IPD over time. Because clinical and behavioral data are lacking in the nationwide surveillance, this was complemented with a multicenter sub-analysis for 248 serotype 4 cases (2020 to mid-2024), which represented 61% of all serotype 4 IPD cases within that period. Patient records were retrospectively consulted, and information was captured in REDCap.
RESULTS: A notable resurgence of serotype 4 IPD cases was noticed, beginning in 2020 and peaked in 2023 as the third most common serotype causing IPD in Belgium. This increase was primarily seen among young adult males (18-49 years old) residing in large urban areas (Brussels Capital Region, Antwerp, Liège, Namur, and Hainaut). The sub-analysis revealed that a high proportion of these patients were unemployed (60.9%), experienced homelessness or unstable housing (30.2%), and reported substance use (72.6%). Tobacco (63.3%) and heavy alcohol consumption (35.1%) were the most reported, whereas a subgroup used hard drugs (26.6%).
CONCLUSION: This study identifies a specific population of vulnerable adults at risk for serotype 4 IPD, emphasizing the need for a specific prevention strategy. Vaccination of this risk group with a pneumococcal vaccine targeting serotype 4 is needed to reduce the increasing burden of invasive disease caused by this vaccine serotype.
Disciplines :
Immunology & infectious disease
Author, co-author :
Cuypers, Lize ; Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, Leuven, Belgium, Department of Laboratory Medicine, National Reference Centre for Invasive Pneumococci, University Hospitals Leuven, Leuven, Belgium. Electronic address: lize.cuypers@uzleuven.be
Sanchez, Gerardo J; Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, Leuven, Belgium
Herrera Avila, Juan Paulo; Department of internal medicine and infectiology, Ziekenhuis aan de Stroom, Antwerp, Belgium
Naesens, Reinout; Department of Laboratory Medicine, Ziekenhuis aan de Stroom, Antwerp, Belgium
Antoine-Moussiaux, Thomas; Department of Internal Medicine and Infectious Diseases, Iris Hospitals South, Brussels, Belgium
Herens, Sophie; Department of Laboratory Medicine, Groupe Santé CHC - MontLégia, Liège, Belgium
Holemans, Xavier; Department of internal medicine and infectious diseases, Grand Hôpital de Charleroi - Les Viviers, Charleroi, Belgium
Darcis, Gilles ; Université de Liège - ULiège > Département des sciences cliniques > Immunopathologie - Maladies infectieuses et médecine interne générale
Layeux, Brice; Department of internal medicine and infectious diseases, CHIREC, Brussels, Belgium
Buttafuoco, Fabrizio; Department of Infectious Diseases, CHU Charleroi, Lodelinsart, Belgium
Brassinne, Laetitia; Laboratory of Clinical Microbiology, Cliniques de L'Europe, Brussels, Belgium
Paridaens, Henry; Department of Laboratory Medicine, Centre Hospitalier Régional de la Citadelle, Liege, Belgium
Hites, Maya; Clinic of Infectious Diseases, Hôpital Universitaire de Bruxelles (HUB) - Université Libre de Bruxelles (ULB), Brussels, Belgium
Lagrou, Katrien; Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, Leuven, Belgium, Department of Laboratory Medicine, National Reference Centre for Invasive Pneumococci, University Hospitals Leuven, Leuven, Belgium
Dauby, Nicolas; Department of Infectious Diseases, CHU Saint-Pierre - Université Libre de Bruxelles (ULB), Brussels, Belgium, School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
Desmet, Stefanie; Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, Leuven, Belgium, Department of Laboratory Medicine, National Reference Centre for Invasive Pneumococci, University Hospitals Leuven, Leuven, Belgium
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