Respiratory Syncytial Virus (RSV) is a common respiratory infection impacting the lungs and breathing passages. Most children encounter this virus by their second birthday. While RSV often presents as a mild, cold-like illness in older children and adults, it poses a significant health concern for infants, sometimes necessitating hospitalization. Accurate diagnosis and appropriate care are important for this vulnerable group.
Recognizing RSV Symptoms and When to Seek Testing
RSV symptoms in infants can vary, from mild cold-like signs to severe respiratory distress. Initially, an infant might exhibit a runny nose, sneezing, a cough, or a low-grade fever, similar to a common cold. They may also show decreased appetite, fussiness, or unusual tiredness. These early symptoms often appear within four to six days after exposure.
The infection can progress to affect the lower respiratory tract, leading to conditions like bronchiolitis or pneumonia. Signs requiring medical attention include short, shallow, rapid breathing, or visible struggling to breathe where the chest muscles and skin pull inward with each breath. Watch for flaring nostrils, grunting sounds during breathing, or a bluish tint to the lips, mouth, or fingernails. Pauses in breathing (apnea) or significant dehydration due to poor feeding also signal a need for medical evaluation. Seek medical advice if an infant displays these concerning symptoms or if mild symptoms worsen.
Common Methods for RSV Testing
Testing for RSV in infants typically involves collecting a fluid sample from the nose, using nasal aspiration or nasopharyngeal swabbing. Nasal aspiration is a common technique where a healthcare professional introduces sterile saline solution into the infant’s nostril. This flushes out nasal secretions, which are then suctioned back out for laboratory analysis.
Alternatively, a nasopharyngeal swab collects a specimen. A specialized, thin swab is carefully inserted into the nasal passage until it reaches the nasopharynx, the upper part of the throat behind the nose. The swab is gently rotated for 10 to 15 seconds to collect cells and secretions before being withdrawn. Nasal aspirate or wash is often preferred for infants due to its ability to yield a larger, more comprehensive sample.
Once collected, samples are analyzed using laboratory tests. Rapid antigen tests are commonly used, providing results within an hour. These tests detect specific proteins (antigens) on the RSV virus surface. Rapid antigen tests have a sensitivity of approximately 80% to 90% in infants and young children.
For more precise detection, molecular tests, such as Polymerase Chain Reaction (PCR) tests, are utilized. PCR tests identify the genetic material (RNA) of the virus and are highly sensitive, detecting smaller amounts of the virus than antigen tests. Samples for PCR testing are usually sent to a laboratory, with results taking longer to obtain.
The medical community uses Current Procedural Terminology (CPT) codes for billing and documentation. For rapid RSV antigen detection immunoassays, code 87807 is typically used. For nucleic acid detection of RSV (PCR), code 87634 is applied. Multiplex PCR tests, detecting RSV alongside other respiratory viruses like influenza and SARS-CoV-2, use codes such as 87637.
Interpreting Results and Managing RSV in Infants
Understanding RSV test results guides an infant’s care. A positive result indicates the presence of the RSV virus. Conversely, a negative result means the virus was not detected. A negative result does not completely rule out an RSV infection, as there might not have been enough virus in the sample, or it was collected too late. Antigen tests, in particular, may have modest performance, and their interpretation can be influenced by community RSV prevalence.
Managing RSV in infants primarily focuses on supportive care to alleviate symptoms and ensure adequate hydration and breathing. Most mild RSV cases can be managed at home. Encouraging frequent, small amounts of fluids, such as breast milk, formula, or water, helps prevent dehydration.
Clearing nasal congestion with saline drops and gentle suction improves an infant’s ability to breathe and feed. A cool-mist humidifier in the infant’s room helps ease respiratory discomfort. Over-the-counter fever-reducing medications, such as acetaminophen or ibuprofen (for infants over six months), can be given as directed by a healthcare provider for fever or discomfort.
For more severe cases, hospitalization may be necessary. Infants who experience significant breathing difficulties, show signs of dehydration despite home care, or have apnea may require hospital admission. In a hospital setting, care can include supplemental oxygen, intravenous fluids for hydration, and, in rare instances, mechanical ventilation if respiratory failure occurs.
Most infants who require hospitalization for RSV improve with supportive care and are discharged within a few days. While there is no specific antiviral treatment for RSV for all infants, Palivizumab (Synagis) is a monoclonal antibody used to prevent severe RSV disease in high-risk infants, such as those born prematurely or with certain heart or lung conditions. It is administered monthly during RSV season and is a preventive measure, not a treatment for an active infection.