PP6 -Retrospective study on the prevalence of human metapneumovirus in samples from the National Respiratory Reference Laboratory (Feb. 2022-Feb. 2024)

Abstract

Introduction

Human metapneumovirus (HMPV) causes upper and lower respiratory infections, primarily affecting infants, young children, the elderly, and immunocompromised individuals. This retrospective analysis evaluated HMPV detection in samples from patients with clinically suspected acute respiratory tract infections referred for multiplex respiratory testing.

Objectives

To determine the HMPV positivity rate and to assess the association between demographic characteristics, clinical presentation, and laboratory findings.

Design, Setting, and Methods

A retrospective analysis was conducted on 131 respiratory samples collected via oropharyngeal and nasopharyngeal swabs from hospitalized patients with suspected acute respiratory infections (Feb 2022–Feb 2024). Clinical and demographic data were extracted from request forms. Samples were tested using the validated, CE/IVD-certified FastTrack® Respiratory Pathogens 21 multiplex PCR. The chi-square test (p < 0.05) was used to assess the associations between categorical variables and HMPV positivity.

Results

The age of participants ranged from newborn to 81 years (mean: 15 years), with 52.6% being male. HMPV positivity was 7.6% (10/131; 95% CI: 3.7%–13.5%). Positive cases ranged from 10 months to 73 years (mean 20.8 years), with the distribution as follows: <1 year (1), 1–10 years (3), 11–45 years (3), 46–65 years (1), and >66 years (2). Three patients had upper respiratory tract infections, and seven had lower respiratory tract infections. Four required ICU admissions (10 months, 13, 68, and 73 years); elderly patients had comorbidities (diabetes, hypertension). Influenza B co-infection was seen in a 13-year-old. No statistically significant correlation was present between HMPV positivity and age group, comorbidity status, ICU admission, or presentation.

Conclusion

Human metapneumovirus showed a low positivity rate, with cases spanning all age groups, highlighting its potential to infect across the spectrum. Lower respiratory tract infection was common in positive cases. Detection among ICU admissions and comorbid individuals indicates possible severity in risk groups. However, findings are limited by selection bias and are not generalizable to population incidence. Further research is needed to clarify the relationship between age, clinical severity, and outcomes and to guide prevention and clinical management.