What is the management and treatment of human metapneumovirus (HMPV) infection?

Management and Treatment of Human Metapneumovirus (HMPV) Infection

Treatment of human metapneumovirus infection is primarily supportive, focusing on symptom management, as there are currently no specific antiviral therapies or vaccines approved for HMPV. 1

Diagnosis

• Low-dose chest CT is indicated in patients with symptoms consistent with lower respiratory tract disease 1
• Diagnosis is mostly based on nucleic acid amplification tests such as reverse transcriptase polymerase chain reaction, as culturing the virus is relatively difficult 2

Treatment Approach

Supportive Care

• Focus on symptom management and respiratory support
• For severe cases with ARDS:
  • Implement mechanical ventilation with a low tidal-volume strategy
  • Use conservative fluid management for patients without tissue hypoperfusion 1
  • Consider extracorporeal membrane oxygenation (ECMO) in cases of severe refractory hypoxemia when standard therapy fails 1, 3

Antimicrobial Considerations

• Empiric antibiotics should only be considered if bacterial superinfection is suspected
• Avoid blind or improper combination of broad-spectrum antibiotics 1
• If influenza co-infection is suspected and within 48 hours of symptom onset, consider oseltamivir or baloxavir 1

Experimental Therapies

• Ribavirin and immunoglobulins have been used in some severe cases, but their efficacy remains unclear 4
• No specific antivirals are currently recommended for routine use 3, 5

Infection Control and Prevention

• Implement hand hygiene with alcohol-based hand gels
• Practice respiratory/cough etiquette
• Isolate infected individuals to prevent spread 1
• Extended isolation precautions should be taken for immunocompromised patients due to potential for prolonged viral shedding 1

Patient Monitoring and Follow-up

• Closer follow-up is required for patients with:
  • Underlying conditions
  • Immunocompromised status (especially HSCT recipients)
  • Advanced age (>65 years) 1, 4
• Be aware that viral shedding can be prolonged in immunocompromised patients, who may remain contagious for weeks 1

Special Considerations

Risk Factors for Severe Disease

• High viral load
• Coinfection with other respiratory pathogens (especially RSV)
• Age: 0-5 months or >65 years
• Immunodeficiency 4

Future Directions

• Several monoclonal antibodies targeting the HMPV fusion protein show promise in preclinical studies
• Vaccine development (subunit, live attenuated, vector-based, and mRNA platforms) is ongoing
• Multivalent approaches targeting multiple respiratory viruses are being explored 5

Clinical Pitfalls to Avoid

• Overuse of antibiotics when bacterial coinfection is not suspected
• Failure to consider ECMO early in cases of severe, refractory hypoxemia
• Inadequate isolation precautions, particularly for immunocompromised patients
• Underestimating the severity potential in high-risk groups (very young, elderly, immunocompromised)
• Assuming short contagious periods in immunocompromised patients who may shed virus for extended periods