TOPLINE

In a meta-analysis of 94 studies, patients with laboratory-confirmed human metapneumovirus (HMPV) infection had increased risk for hospitalization, and among those hospitalized, 12% required ICU admission, 40% required respiratory support, and 3% died during hospitalization. Mortality was the highest among adults, reaching 6%.

METHODOLOGY

• Researchers conducted a systematic review and meta-analysis of studies from high-, middle-, and low-income countries across North America, Europe, Asia, Africa, and Latin America to estimate the proportion of patients with laboratory-confirmed HMPV infection having severe outcomes.
• They included 94 observational studies comprising approximately 26,000 patients showing HMPV positivity; HMPV infection was confirmed primarily using reverse transcription polymerase chain reaction or nucleic acid amplification tests.
• The primary outcomes included hospitalization, ICU admission, supplemental respiratory support, mechanical ventilation, and in-hospital mortality; other outcomes included hospital length of stay and ICU length of stay.
• Researchers estimated pooled proportions and compared the results by healthcare setting and age. Study periods ranged from 1976 to 2026, with most studies (74.5%) using cohort designs and the majority (64.9%) being conducted in hospital-based settings.

TAKEAWAY

• Across all included studies, the pooled proportion of patients with laboratory-confirmed HMPV infection requiring hospitalization was 48%. Among hospitalized patients, the pooled ICU admission proportion was 12% (26 studies, n = 14,522), with significant differences by setting (P = .04): 10% across hospital-based studies, 34% across mixed-setting studies, and 13% across studies with other settings.
• Across 18 studies, the pooled proportion of hospitalized patients who needed supplemental respiratory support was 40%, with no significant difference by setting (P = .31).
• The pooled proportion of hospitalized patients who required mechanical ventilation was 8% across 16 studies, with significant differences by setting (P < .001): 6% across hospital-based studies, 20% across ICU-based studies, and 15% across mixed-setting studies.
• The pooled in-hospital mortality rate was 3% across 29 studies, with significant differences by age group (P < .01): 6% among adults, 3% among pediatric patients, and 2% among mixed-age populations. Hospital length of stay varied widely across studies, with the median lengths of stay ranging from 1.5 to 24 days in children and from 3 to 10 days in adults. The median ICU length of stay was generally 2-4 days across eight studies.

IN PRACTICE

"The most immediate implications are to strengthen HMPV surveillance, standardize outcome and denominator reporting, and generate prospective evidence that permits more reliable risk stratification," the authors of the study wrote.

SOURCE

The study was led by Yu Miao, MS, Franklin College of Arts and Sciences, University of Georgia, Athens. It was published online on October 8, 2026, in Open Forum Infectious Diseases.

LIMITATIONS

Substantial heterogeneity across studies reflected differences in patient populations, study designs, diagnostic methods, case definitions, admission thresholds, healthcare infrastructure, and reporting quality. Hospitalization estimates may have been inflated by selection bias because patients with more severe illness were more likely to be tested for HMPV. Few studies came from low- and lower-middle-income countries, so the findings may not apply to resource-limited settings.

DISCLOSURES

This study was supported by two grants. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.