Is respiratory syncytial virus (RSV) highly contagious and how is it transmitted?

Is RSV Highly Contagious?

Yes, respiratory syncytial virus (RSV) is highly contagious and spreads readily through multiple transmission routes, making it a significant infection control concern in both healthcare and community settings. 1, 2, 3

Primary Transmission Mechanisms

RSV transmission occurs through three well-documented pathways that make it particularly contagious:

• Large respiratory droplets are expelled during close contact with symptomatic infected persons, representing the direct transmission route 1
• Contaminated hands serve as the primary vehicle for indirect transmission, with hands becoming contaminated either by touching respiratory secretions of infected persons or by handling contaminated objects 1
• Fomites (contaminated surfaces) harbor viable RSV and facilitate spread, as infected individuals—especially infants—shed large amounts of virus that easily contaminates their immediate surroundings 1

Portal of Entry and Inoculation

The virus gains entry through specific anatomical sites that are frequently touched:

• The conjunctiva (eyes) and nasal mucosa are the usual portals of entry for RSV 1
• Self-inoculation occurs when RSV-contaminated hands deposit the virus onto the eyes or nose, which is the most common mechanism of infection 1

Viral Shedding and Infectious Period

The duration of contagiousness varies significantly by population:

• Infants and young children typically shed virus for 1-3 weeks during active infection, requiring isolation precautions throughout hospitalization 4
• Infected infants shed large amounts of virus in their respiratory secretions, making them a major reservoir for RSV transmission 1
• Individuals are infectious even before symptomatic presentation begins, and remain contagious as long as viral shedding continues 3
• The length of viral shedding differs based on infection severity, patient age, and underlying immune status 3

Healthcare and Community Spread Patterns

Multiple sources contribute to RSV outbreaks in healthcare settings:

• More than one strain of RSV is often identified during nosocomial outbreaks, suggesting multiple simultaneous sources of the virus 1
• Healthcare workers can become infected after community or hospital exposure and subsequently transmit infection to patients, other staff, or visitors 1
• Patients, healthcare workers, and visitors all serve as potential sources during outbreaks 1

Seasonal Patterns and High-Risk Settings

RSV demonstrates predictable epidemic behavior:

• Community outbreaks occur seasonally from December through March in the U.S., lasting 3-5 months and associated with increased hospitalizations and deaths among infants and young children 1
• Children with respiratory symptoms at hospital admission during community outbreaks are often reservoirs for RSV 1
• Patients living in residential facilities have a 4.43-fold greater likelihood of severe RSV infection compared to community-dwelling individuals, reflecting the highly contagious nature in congregate settings 1

Critical Infection Control Implications

The high contagiousness of RSV necessitates specific precautions:

• Contact-isolation precautions are essential, with successful prevention programs sharing two common elements: implementation of contact isolation and healthcare worker compliance with these precautions 1
• Wearing gloves and gowns during contact with RSV-infected patients or their immediate environment has been successful in preventing transmission 1
• Handwashing alone, while theoretically capable of preventing most nosocomial RSV infections, shows poor compliance among healthcare workers in practice, necessitating additional preventive measures 1

Common Pitfalls to Avoid

• Do not assume gloves alone provide protection—gloves must be changed after each patient contact and hands must be washed adequately after glove removal, or the benefits are completely offset 1
• Do not underestimate surface contamination—RSV survives on fomites and requires environmental cleaning in addition to hand hygiene 1
• Do not rely solely on symptomatic screening—individuals are contagious before symptoms appear, making universal precautions essential during RSV season 3