Mancon Alessandro, Pellegrinelli Laura, Romano Greta, Vian Elisa, Biscaro Valeria, Piccirilli Giulia, Lazzarotto Tiziana, Uceda Renteria Sara, Callegaro Annapaola, Pagani Elisabetta, Masi Elisa, Ferrari Guglielmo, Galli Cristina, Centrone Francesca, Chironna Maria, Tiberio Claudia, Falco Erasmo, Micheli Valeria, Novazzi Federica, Mancini Nicasio, Allice Tiziano Giacomo, Cerutti Francesco, Pomari Elena, Castilletti Concetta, Lalle Eleonora, Maggi Fabrizio, Fracella Matteo, Ravanini Paolo, Faolotto Giulia, Schiavo Roberta, Lo Cascio Giuliana, Acciarri Carla, Menzo Stefano, Baldanti Fausto, Antonelli Guido, Pierangeli Alessandra, Pariani Elena, Piralla Antonio
Laboratory of Clinical Microbiology, Virology and Bioemergencies, Azienda Socio Sanitaria Territoriale Fatebenefratelli Sacco, Milan, Italy.
Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
J Infect Dis. 2025 Jul 16;232(Supplement_1):S109-S120. doi: 10.1093/infdis/jiaf111.
Human metapneumovirus (hMPV) infections have a significant impact on public health. However, the extent of this burden in Italy remains poorly defined due to a lack of comprehensive data. The aim of this cross-sectional multicenter study was to understand the epidemiology of hMPV in Italy, particularly in older adults.
We analyzed laboratory data from molecular respiratory viral diagnostic tests conducted at 17 centers across Italy from September 2022 to August 2024. Respiratory viruses were tested from outpatients for epidemiologic surveillance and from patients presenting to tertiary hospitals for diagnostic purpose. G gene sequencing was performed on a limited number of circulating strains.
Data from 96 460 tests yielded an overall hMPV positivity rate of 3.4%; the hMPV positivity rate was 2.6% in adults aged 50 years and older, a third of whom were aged >80 years. In north-west Italy, hMPV was detected more frequently in outpatients than in hospitalized patients. The temporal distribution of cases showed seasonal peaks in February 2023 and April 2024, which exhibited some geographic variation but overlapped in the general population and in the elderly. Phylogenetic analysis suggested an even distribution of hMPV-A and -B, with a predominance of clades A2c with a 111-nucleotide duplication and B2b, and the possible extinction of previously circulating clades A2c with a 180-nucleotide duplication and B2a.
hMPV was shown to be a relevant respiratory pathogen in older adults, who could be more likely to have severe outcomes. These findings may inform hMPV surveillance and the development of prevention strategies.
人偏肺病毒（hMPV）感染对公共卫生有重大影响。然而，由于缺乏全面数据，意大利这种负担的程度仍不清楚。这项横断面多中心研究的目的是了解意大利hMPV的流行病学，特别是在老年人中的情况。
我们分析了2022年9月至2024年8月在意大利17个中心进行的分子呼吸道病毒诊断检测的实验室数据。对门诊患者进行呼吸道病毒检测用于流行病学监测，对三级医院就诊患者进行检测用于诊断目的。对有限数量的流行毒株进行了G基因测序。
96460次检测的数据显示hMPV总体阳性率为3.4%；50岁及以上成年人中hMPV阳性率为2.6%，其中三分之一年龄大于80岁。在意大利西北部，门诊患者中hMPV的检出率高于住院患者。病例的时间分布显示在2023年2月和2024年4月出现季节性高峰，在不同地区有一定差异，但在普通人群和老年人中出现重叠。系统发育分析表明hMPV-A和-B分布均匀，以带有111个核苷酸重复的A2c分支和B2b为主，之前流行的带有180个核苷酸重复的A2c分支和B2a分支可能已消失。
hMPV被证明是老年人中一种重要的呼吸道病原体，老年人可能更易出现严重后果。这些发现可为hMPV监测和预防策略的制定提供参考。
