New research indicates people infected with Respiratory Syncytial Virus (RSV) may be highly infectious for approximately five days. This finding stems from a study of 225 adults experimentally infected with RSV, which mapped the virus's behavior inside the body.
The analysis showed infectious virus becomes detectable around three days post-exposure and is typically cleared by day eight, establishing a median infectious window of about five days. However, viral RNA, detected in diagnostic tests, persisted significantly longer, with a median clearance time of 12 days. This distinction means patients may continue to test positive after they are no longer infectious.
Both innate and adaptive immune responses are critical in controlling RSV infection. Early innate immunity limits viral production, while adaptive responses, including antibodies, drive the clearance of infected cells. Non-antibody immune responses were found to increase infected cell clearance rates significantly.
Researchers also linked symptoms to transmission risk. Individuals with minimal symptoms contributed only a small percentage of total infectious viral shedding, suggesting those with more pronounced symptoms play a larger role in transmission.
These insights could refine isolation guidance, testing strategies, and infection control policies, aiding clinicians in interpreting test results and managing patients more effectively. The study offers a more targeted approach to RSV diagnosis, isolation, and prevention at both individual and population levels.