INFLUENZA VIRUS CIRCULATION DURING 2024-2025 SEASON IN RABAT, MOROCCO

Abstract

Introduction: Influenza remains a major cause of respiratory morbidity worldwide. The World Health Organization (WHO) estimates that seasonal influenza epidemic is responsible for millions of severe infections and hundreds of thousands of deaths each year. Global surveillance of influenza viruses is coordinated via the World Health Organization Global Influenza Surveillance and Response System (GISRS). The organization follows circulating influenza virus on all continents and provides relevant information for vaccine strain selection as well as public health considerations. This study describes the circulation patterns of influenza viruses at Mohammed V Military Teaching Hospital (MVMTH) in Rabat during the 2024-2025 Influenza season. Methods: A prospective observational study was conducted from October 2024 to March 2025. Nasopharyngeal swabs from patients with influenza-like illness were analyzed using RT-PCR (Film Array Respiratory Panel and GeneXpert Xpress Flu/RSV). Results: Influenza A viruses showed up in most of the tested samples. Among influenza A viruses, viral A(H1N1)pdm09 infection was detected the most commonly. Influenza B viruses were also recorded but circulated at lower levels during the surveillance period. One hundred and sixteen cases were confirmed. Influenza A predominated (80%; n=93), while Influenza B accounted for 20% (n=23). Among Type A cases, A(H1N1)pd2009 was the primary subtype identified (64.5%; n=60), followed by non-subtyped strains (35.5%; n=33). A(H3N2) circulation was marginal (2.8%). Temporally, A(H1N1) peaked in week 4 of 2025, whereas Influenza B showed dominant activity in the late season (Weeks 14-17). Conclusion: The 2024-2025 season was characterized by the dominance of Influenza A(H1N1) and a late-season shift to Influenza B. These findings highlight the necessity of local surveillance to optimize hospital resource allocation and vaccination timing in Morocco.