Respiratory Syncytial Virus (RSV) is a common respiratory virus that infects the lungs and breathing passages. Almost all children encounter the virus by their second birthday. While RSV can affect individuals of all ages, it often presents with symptoms similar to a common cold. Understanding the typical progression of RSV, particularly when symptoms are most intense, can help parents and caregivers.
Typical RSV Symptom Progression
Symptoms of RSV infection typically emerge within four to six days after exposure. The initial phase often begins subtly, resembling a common cold. Early signs can include a runny nose, sneezing, a mild cough, and sometimes a low-grade fever.
These initial symptoms may not all appear simultaneously, often developing in stages. For very young infants, irritability, decreased activity, and difficulty feeding might be the only initial symptoms.
The Peak of RSV Symptoms
RSV symptoms generally reach their peak intensity between day 3 and day 5 after they first appear. This period marks when the illness is typically at its worst. During this peak, the cough often becomes more frequent and severe, and a high-pitched whistling sound during breathing, known as wheezing, may develop or intensify.
Breathing can become rapid or labored, causing noticeable discomfort. Fever might also be higher during this phase. While this is the most intense phase, symptoms should gradually start to subside afterward.
Recognizing Severe RSV
While many RSV cases remain mild, certain signs indicate a more severe infection requiring prompt medical attention. Difficulty breathing is a significant concern, manifesting as retractions (skin pulling in between or under the ribs with each breath) or nasal flaring (nostrils widening with each breath). Rapid, shallow breathing or pauses in breathing, especially in infants, are also serious indicators.
A bluish discoloration of the skin around the mouth or fingernails (cyanosis) signals a lack of oxygen and warrants immediate medical care. Signs of dehydration, such as fewer wet diapers, no tears, dry mouth, or decreased urine output, are also concerning. Extreme lethargy, unusual tiredness, or increased irritability in infants necessitate medical evaluation, particularly in high-risk groups like babies under six months old.
Recovery and Lingering Symptoms
Following the peak, typically around day 5, RSV symptoms usually begin to gradually improve. The overall illness often resolves within one to two weeks for most people. However, a cough and wheezing can persist for several weeks even after other symptoms have cleared.
For some, especially infants or those with underlying conditions, full recovery may extend beyond this timeframe.