Treatment of Human Metapneumovirus (HMPV) Infection
There is no proven antiviral therapy for HMPV infection; treatment is entirely supportive care, as no antiviral agent has established efficacy for HMPV in adults. 1
General Population Management
Supportive care is the only recommended approach for HMPV infection in immunocompetent patients. 1 This includes:
- Hydration and oxygen supplementation as needed 2
- Monitoring for bacterial superinfection, particularly with Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae 1
- Symptomatic management of flu-like symptoms including fever, cough, and rhinorrhea 1
The clinical course is typically mild and self-limiting in immunocompetent adults, though severe disease can occur in elderly patients and those with chronic cardiopulmonary conditions. 3, 4
Immunocompromised Patients (HSCT Recipients, Leukemia Patients)
No general recommendation for treatment can currently be made for HMPV in immunocompromised patients, though some centers empirically treat lower respiratory tract disease (LRTID) with ribavirin and/or IVIG despite lack of supporting studies. 1
Risk Stratification
High-risk features that may prompt consideration of empiric therapy include: 1
- Cytomegalovirus seropositivity 1
- Neutropenia or lymphopenia 1
- Higher corticosteroid exposure 1
- Infection early after allogeneic HSCT 1
- Coinfections with bacteria, fungi, other respiratory viruses, or CMV 1
Empiric Treatment Considerations
Some centers consider ribavirin with or without IVIG for HMPV LRTID in high-risk patients, though this lacks randomized controlled trial support. 1, 2
This approach is extrapolated from experience with related paramyxoviruses (RSV, parainfluenza), but efficacy data specific to HMPV are absent. 1, 4
Critical Pitfalls to Avoid
- Do not use influenza antivirals (oseltamivir, zanamivir, baloxavir) or adamantanes (amantadine, rimantadine) for HMPV—they have zero activity against this virus. 2
- Use multiplex PCR panels to distinguish HMPV from influenza and other respiratory viruses, as management differs fundamentally. 1, 2
- Recognize that asymptomatic shedding occurs frequently (up to 41% in some studies), requiring isolation precautions in healthcare settings. 1
- Be vigilant for coinfections—HMPV is frequently codetected with other pathogens in pneumonia cases, obscuring attributable morbidity. 1
Severe Disease Management
For severe ARDS complicating HMPV infection with refractory hypoxemia, veno-venous ECMO may be considered as rescue therapy. 5
Standard ARDS management principles apply, including lung-protective ventilation and prone positioning when indicated. 5
Future Directions
No vaccines or approved antivirals are currently available for HMPV. 6, 3, 7 Monoclonal antibodies targeting the fusion protein and various vaccine platforms (subunit, live attenuated, mRNA) are in development but none have reached clinical trials. 7