The Global Burden of Human Metapneumovirus in High-Risk Adults: A Systematic Literature Review and Meta-Analysis.

Abstract

Background: Human metapneumovirus (hMPV) is an under-recognized cause of severe respiratory illness in high-risk adults. We conducted a systematic review and meta-analysis to quantify hMPV prevalence and clinical outcomes in adults with chronic underlying conditions predisposing them to severe respiratory illness, including the immunocompromised.

Methods: We searched MEDLINE, Embase, and BioRelate (January 2010 to February 2025) for studies of laboratory-confirmed hMPV in adults (≥ 18 years) with high-risk chronic or immunocompromising conditions. We extracted data on hMPV positivity and key outcomes (hospitalization, intensive care unit [ICU] admission, respiratory support, length of stay, and mortality). We performed random-effects meta-analyses for outcomes reported in ≥ 3 studies and assessed study quality using an adapted Joanna Briggs Institute checklist.

Results: We included 72 studies. Among immunocompromised adults with hMPV infection, 55.2% (95% confidence interval [CI], 42.0-67.7%) required hospital admission. Among immunocompromised patients hospitalized with respiratory illness, hMPV was detected in 5.4% (95% CI, 2.7-10.8%). Among patients with cardiovascular disease, 11.4% (95% CI, 8.0-16.1%) tested positive for hMPV. Regarding patients with chronic respiratory conditions, 3.4% (95% CI, 2.4-5.0%) of patients with chronic obstructive pulmonary disease exacerbations and 7.6% (95% CI, 2.5-20.5%) of patients with asthma exacerbations were hMPV-positive. Among hospitalized hMPV-positive high-risk patients, 13.0% (95% CI, 8.8-18.9%) required ICU admission, 43.6% (95% CI, 34.9-52.7%) required supplemental oxygen, and 7.3% (95% CI, 1.2-33.8%) required mechanical ventilation. The mean length of hospital stay was 10.4 days (95% CI, 3.4-17.4%). The pooled case fatality ratio among hospitalized adults with hMPV infection was 2.4% (95% CI, 0.1-35.1%).

Conclusions: hMPV is a substantial cause of severe respiratory illness in high-risk adults. Enhanced detection, surveillance, and preventive strategies are needed to reduce hMPV-associated morbidity in vulnerable populations.