Treatment of Human Metapneumovirus (hMPV) Infection
There is currently no specific antiviral therapy approved for hMPV infection; treatment remains primarily supportive care, though some centers consider ribavirin and/or IVIG for severe lower respiratory tract disease in immunocompromised patients, particularly those with hematopoietic stem cell transplantation (HSCT). 1
General Population Management
Supportive Care as Primary Treatment
- Supportive care is the mainstay of treatment for hMPV infections in immunocompetent patients, as no effective antiviral agents or vaccines are currently approved for clinical use 2, 3, 4
- Oxygen therapy should be provided based on severity: nasal cannula, mask oxygen, high-flow nasal oxygen therapy (HFNO), non-invasive ventilation (NIV), or invasive mechanical ventilation as needed 1
- Monitor vital signs including heart rate, pulse oximetry, respiratory rate, and blood pressure 1
Severe Disease Management
- For refractory hypoxemia despite maximal ventilatory support, consider veno-venous extracorporeal membrane oxygenation (V-V ECMO) as rescue therapy 5
- This is particularly relevant for patients developing severe acute respiratory distress syndrome (ARDS) from hMPV infection 5
Immunocompromised Patients (HSCT Recipients)
Risk Stratification
The following factors increase risk of progression to lower respiratory tract infection disease (LRTID) and warrant closer monitoring 1:
- Higher corticosteroid exposure
- Neutropenia or lymphopenia
- Infection occurring early after allogeneic HSCT
- Higher APACHE II score
- Presence of coinfections (bacteria, fungi, other respiratory viruses, cytomegalovirus)
- Recipient cytomegalovirus seropositivity 1
Treatment Considerations for LRTID
- Some centers consider treating hMPV LRTID with ribavirin and/or intravenous immunoglobulin (IVIG), despite lack of supporting randomized controlled trials 1
- This approach is extrapolated from experience with other paramyxoviruses, though efficacy remains unclear 3
- No general recommendation for treatment can be made given the absence of high-quality evidence 1
Key Clinical Pitfalls
Coinfection Recognition
- hMPV is frequently codetected with other pathogens including bacteria, fungi, other respiratory viruses, and cytomegalovirus, which obscures attributable morbidity 1
- Obtain appropriate cultures and molecular testing to identify copathogens that may require specific antimicrobial therapy 1
Asymptomatic Shedding
- Asymptomatic and prolonged viral shedding has been documented in HSCT patients, complicating infection control efforts 1
- Implement appropriate isolation precautions even in minimally symptomatic patients 1
Emerging Therapeutic Approaches
Monoclonal Antibodies (Investigational)
- Neutralizing monoclonal antibodies against hMPV fusion protein (such as mAb364/MPV364) show promise in preclinical studies when delivered via intranasal route 6
- Intranasal delivery reduced viral titers by approximately four logs within 2 days in animal models and alleviated key pathological outcomes 6
- Apical (respiratory tract) delivery is critical, as basolateral delivery is ineffective even at 100-fold higher concentrations 6
- These agents are not yet approved for clinical use 6