Contagious Period for Human Metapneumovirus (HMPV)
Human metapneumovirus has a contagious period that typically lasts 2-5 days after symptom onset, with prolonged shedding commonly observed in immunocompromised patients, particularly hematopoietic stem cell transplant recipients. 1
Viral Characteristics and Transmission
Human metapneumovirus (HMPV) is a paramyxovirus closely related to respiratory syncytial virus (RSV) that causes respiratory infections ranging from mild upper respiratory tract infections to severe pneumonia. The virus is transmitted through:
- Respiratory droplets from coughing or sneezing
- Close contact with infected individuals
- Contact with contaminated surfaces
Key transmission characteristics include:
- Incubation period: 3-6 days 1
- Typical illness duration: 2-5 days in immunocompetent hosts 1
- Viral shedding: Can be prolonged, especially in immunocompromised patients 2
Contagious Period in Different Populations
General Population
- Most infectious during the symptomatic phase (first 2-5 days of illness) 1
- Symptoms typically resolve on their own within 5 days in healthy individuals 1
Immunocompromised Patients
- Asymptomatic and prolonged shedding has been well-documented in hematopoietic stem cell transplant (HSCT) recipients 2
- HSCT patients may shed virus for extended periods, potentially remaining contagious for weeks 2, 3
- This prolonged shedding contributes to nosocomial outbreaks in healthcare settings 2
Clinical Implications and Management
Infection Control Measures
- Hand hygiene with alcohol-based hand gels
- Respiratory/cough etiquette
- Isolation of infected individuals, especially in healthcare settings 3
- Consider extended isolation precautions for immunocompromised patients due to prolonged shedding 2
High-Risk Populations
The following groups are at higher risk for severe HMPV infection and potentially longer contagious periods:
- Young children (under 5 years)
- Elderly individuals
- Patients with underlying pulmonary disease
- Immunocompromised individuals, particularly HSCT recipients 4
Seasonal Patterns and Co-Circulation
HMPV typically circulates during winter and spring months with:
- Season onset ranging from November to February
- Season offset from April to July
- Median season duration of 21-22 weeks 5, 6
HMPV often co-circulates with other respiratory viruses, with RSV season typically preceding HMPV season 5, 6.
Important Considerations
- Unlike some other respiratory viruses, there are currently no specific antiviral therapies or vaccines approved for HMPV 7
- Treatment is primarily supportive, focusing on symptom management 3, 1
- In healthcare settings, infection control measures should account for the potential of prolonged shedding in immunocompromised patients 2, 3
Human metapneumovirus should be considered in the differential diagnosis of respiratory infections, particularly during winter and spring months, and appropriate infection control measures should be implemented based on the expected contagious period.