Is a 7‑day‑old infant who tested positive for respiratory syncytial virus (RSV) and continues to cough 7 days after diagnosis still contagious?

Is an Infant with RSV Still Contagious 7 Days After Testing Positive?

Yes, the infant is almost certainly still contagious at 7 days post-diagnosis, as RSV viral shedding typically continues for 1-3 weeks in infants and young children, with some infants shedding virus for up to 3-4 weeks. 1

Duration of Viral Shedding and Contagiousness

Infants remain infectious as long as they are shedding virus, which commonly extends well beyond 7 days:

• RSV viral shedding typically persists for 1-3 weeks in infants and young children, meaning the infant is contagious throughout this entire period 1
• The presence of ongoing cough at day 7 strongly suggests active viral replication and continued shedding 2, 3
• An individual is considered infectious and can transmit RSV even before symptoms begin, and remains contagious throughout the symptomatic period 2
• The length of viral shedding varies based on severity of infection, age of the patient, and immune status, with younger infants and those with more severe disease shedding longer 2

Practical Infection Control Measures

Because the infant remains contagious, strict precautions must continue:

• Hand hygiene is the single most important measure to prevent RSV transmission—hands must be decontaminated before and after direct contact with the infant, after touching objects near the infant, and after removing gloves 1
• Alcohol-based hand rubs are preferred when hands are not visibly soiled 1
• RSV survives on countertops for ≥6 hours, on gowns for 20-30 minutes, and on skin for up to 20 minutes, making surface contamination a major transmission route 4
• RSV RNA has been identified in air samples as far as 22 feet from the patient's bedside, and secretions can be found on beds, crib railings, tabletops, and toys 1
• The virus remains viable and contagious on fomites (contaminated surfaces) for several hours 1

Specific Isolation Recommendations

The infant should remain isolated from vulnerable populations:

• Keep the infant away from crowds, other children (especially those in daycare), elderly individuals, and immunocompromised persons 1, 4
• Restrict visitors, particularly anyone with respiratory symptoms 4
• If the infant requires hospitalization, contact and droplet precautions should be maintained throughout the hospital stay 1
• Programs implementing strict hand hygiene and droplet precautions have decreased nosocomial RSV transmission by 39-50% 4

When Can Isolation Be Relaxed?

Isolation precautions should continue until symptoms have substantially resolved:

• Do not discontinue isolation based solely on the 7-day timeframe or clinical improvement alone, as viral shedding persists even as symptoms improve 4
• The infant can be considered less contagious when respiratory symptoms (cough, congestion, rhinorrhea) have largely resolved, typically 2-3 weeks after symptom onset 5, 3
• Even after clinical improvement, some degree of viral shedding may continue, so continued hand hygiene remains important 2

Common Pitfalls to Avoid

• Do not assume the infant is no longer contagious simply because 7 days have passed—this is well within the typical shedding period 1, 2
• Do not rely on symptom improvement alone to determine contagiousness, as viral shedding can persist despite clinical improvement 4, 2
• Do not underestimate fomite transmission—RSV spreads readily through contaminated surfaces and hands, not just respiratory droplets 1, 6
• Inoculation occurs mainly through the eye and nose rather than the mouth, so hand-to-face contact after touching contaminated surfaces is a major transmission route 6