Prevalence of Human Metapneumovirus in Older Adults Across Ten Affluent Nations

Overview

This study quantifies the incidence of human metapneumovirus (hMPV)-associated lower respiratory infections (LRI) among adults aged 60 and older in ten high-income countries in 2019. Meta-analysis of 21 studies estimated that 7.0% of LRI cases in this population were attributable to hMPV, with incidence rates ranging from 185.7 to 462.1 per 100,000 across countries.

Background

Human metapneumovirus (hMPV) is a respiratory virus first isolated in 2001 but likely circulating for over a century. Nearly all individuals are infected early in life, but immunity is partial and reinfections occur throughout life. Older adults are at increased risk of severe disease, including pneumonia and exacerbations of chronic respiratory conditions. Despite its clinical significance, hMPV epidemiology in older adults remains poorly characterized, and no vaccines are currently available.

Data Highlights

Key Findings

• Meta-analysis of 21 studies found that 7.0% (95% CI, 5.4%–9.1%) of LRI episodes in adults aged ≥60 were associated with hMPV.
• Estimated hMPV incidence rates per 100,000 older adults in 2019 ranged from 185.7 in Italy to 462.1 in the United States.
• hMPV infection in older adults can cause severe respiratory illness, including pneumonia and exacerbations of chronic respiratory diseases.
• Older adults often present with atypical symptoms, leading to underdiagnosis and underreporting of hMPV infections.
• No specific antiviral treatments or vaccines are currently available, though combination vaccines with RSV are in development.
• Inclusion of hMPV in routine respiratory virus surveillance is needed to better understand its burden and guide prevention strategies.

Clinical Implications

Clinicians should consider hMPV as a significant cause of lower respiratory infections in older adults, especially during seasonal peaks. Awareness of atypical presentations in this population may improve diagnosis and management. The substantial burden highlighted supports prioritizing vaccine development and incorporating hMPV testing into routine surveillance to inform public health interventions.

Conclusion

This comprehensive analysis confirms that hMPV is an important contributor to lower respiratory infections among older adults in affluent countries. Enhanced surveillance and targeted preventive strategies, including vaccine development, are warranted to address this underrecognized pathogen.

References

1. Original Article -- Prevalence of Human Metapneumovirus in Older Adults Across Ten Affluent Nations