(106) Epidemiological Landscape of Human Metapneumovirus Among Older Adults in High-Income Countries: Systematic Literature Review and Meta-Analysis

Background: As society learns and adapts to better prepare for potential future public health crises, stakeholders are closely monitoring emerging respiratory viruses such as human metapneumovirus (hMPV). However the epidemiological landscape is poorly characterized due to limited data availability. Understanding the true burden of hMPV, including variation by age, sex, and location, may help inform vaccine development efforts.

Objectives: To systematically identify and evaluate published literature assessing the annual incidence of hMPV among adults aged 60+ years in 10 high income countries from 2000-2019. A meta analysis was conducted to pool available data on the annual proportion of lower respiratory infection (LRI) cases positive for hMPV among adults aged 60+ years from the systematic literature review (SLR).

Methods: Publications were searched and collected through a systematic methodology for English language studies in key biomedical literature databases including PubMed® and Embase®, along with secondary sources where applicable. Studies were independently screened for relevance by 2 researchers with a 3rd reviewer adjudicating disagreements. Studies were screened at 2 levels (title/abstract [T/A] and full text [FT]) using pre specified inclusion and exclusion criteria. Data analysis was focused on hMPV incidence, and proportion of LRI cases positive for hMPV. The SLR is registered with PROSPERO (CRD42023441008).

Results: Among 1,802 T/A and 110 FT studies identified, 51 select studies reported data on the incidence of hMPV among older adults (N=4 studies), the proportion of LRI cases positive for hMPV (N=35), or only the number of hMPV-positive cases (N=12) from 9 countries. Based on the meta-analysis of extracted data of studies from 8 countries included in the base cases analysis (N=29), we estimated that 7.4% (95% confidence interval [CI]: 5.9% – 9.2%) of LRI cases among older adults were positive for hMPV. Although some variations were detected in estimates from subgroup analyses by location (range: 4.4% [95% CI: 2.4% – 8.0%] to 17.2% [95% CI: 12.3% – 24.1%]), findings were similar when adjusting for the age or sex in the analysis (data to be presented).

Conclusions: This SLR and meta-analysis provides a comprehensive summary of available published evidence describing annual incidence of hMPV among adults aged 60+ years across high-income countries. The evidence in some of the high-income locations was limited, highlighting the need for additional data across the globe. Taken together with reliable estimates of LRI from research such as Global Burden of Disease by Institute for Health Metrics and Evaluation, this work will generate actionable data to inform hMPV vaccine development strategies.