Human metapneumovirus epidemiology. Global patterns of hMPV seasonality: comprehensive exploration

Duration: Dec 2025 - Nov 2026

Background

Human metapneumovirus (HMPV) causes acute respiratory infections in humans, particularly during the cold seasons, accounting for 2-9% of all respiratory virus infections.

Previous studies have demonstrated that HMPV is a significant contributor to respiratory infections in young children under five years of age and older adults and is associated with a substantial number of hospitalisations. As HMPV is not routinely tested within national surveillance schemes in most countries, our understanding of HMPV epidemiology primarily relies on clinical practice-based expertise and scientific studies, which remain limited. Existing evidence suggests that HMPV circulation varies across climatic regions and may partially overlap with RSV circulation, although seasonal patterns can shift from year to year, resulting in a complex epidemiological pattern. Recent studies show that HMPV circulation was disrupted during the COVID-19 pandemic. A better understanding of HMPV seasonality is therefore essential for interpreting and anticipating annual circulation patterns. 

Aim

This study has two main objectives:

1. To serve as an early effort to map existing evidence on HMPV seasonality and subtype circulation through a systematic literature review. By combining the available data, this research provides an important step toward understanding HMPV’s seasonal dynamics, national and regional patterns, and its similarity to other respiratory viruses.
2. To assess whether country-level HMPV data from the Global Influenza Hospital Surveillance Network (GIHSN) database are appropriate to perform in-depth HMPV seasonality analyses in participating countries, WHO regions and age groups.

Method

The systematic literature review will follow the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Guiding questions for the review are: 1) In which countries is research being conducted and what are documented seasonal patterns of HMPV circulation; 2) How do patterns compare across cold, temperate and tropical regions in both hemispheres and across age groups (and other possible subgroups). The population-concept-context (PCC) framework will be used to develop review questions and inclusion and exclusion criteria. Screening will be piloted and performed in different phases (title/abstract and full-text screening) and will be done by two independent reviewers. To streamline the process, a web-based application designed for systematic reviews will be used to review the large number of articles. Data synthesis will entail a descriptive numerical summary and thematic analysis, resulting in the identification of key findings and gaps in the extracted evidence.

The data exploration aims to assess the feasibility of using GIHSN data to identify seasonality patterns of HMPV. 
First, a core set of data required for robust seasonality analyses will be defined and the data will be assessed on availability, completeness and quality across countries and seasons. For countries meeting the core set criteria, time series analyses will be planned.

Results

The results of the systematic literature review will be described in a scientific manuscript for an international journal. The assessment of the feasibility of using available country-level HMPV data from GIHSN for time series analyses to capture seasonality will be described in a report.