Why Does Cough Persist After Viral Infections?
If you’ve recently battled respiratory illnesses like flu, COVID-19, or RSV, yet still find yourself dealing with a lingering cough, you’re certainly not alone. Experiencing a persistent cough after overcoming viruses is a common occurrence. According to Dr. Michael Shiloh, an infectious disease expert from the University of Texas, many individuals report coughing for up to eight weeks post-illness. Although the virus is no longer detectable, the cough often lingers.
As per the U.S. Centers for Disease Control and Prevention (CDC), respiratory infections are quite prevalent, with more severe cases on the rise. Visits to emergency rooms due to influenza, RSV, and COVID-19-related symptoms are increasing. Most recover from these illnesses within a few weeks, yet some symptoms, like coughing, tend to persist longer.
The Science Behind the Prolonged Cough
While the exact reasons remain somewhat elusive, research indicates that viral infections may interact with airway nerves to prolong coughing. Coughing serves as an essential reflex to protect and clear our airways from irritants. Pulmonologist Dr. Lorcan McGarvey explains that this reflex is often triggered by harmful substances. Sensitive nerve endings react to cold air or bitter substances, sending signals to the brain to initiate a cough.
Despite usually serving to clear mucus from the throat, some viral infections provoke a dry cough, one that doesn’t produce phlegm. Studies suggest that these infections can make the nerves hypersensitive, potentially causing the cough to persist. Dr. McGarvey notes that even simple actions, like taking a deep breath or laughing, might trigger a coughing fit due to this heightened sensitivity.
Research from the 1990s demonstrated that guinea pigs infected with a flu-like virus exhibited more sensitive nerves. Similarly, in humans, this kind of hypersensitivity is observed. Current investigations highlight that such sensitization is linked to specific receptors in the airway nerves.
When to Seek Medical Advice
Typically, the cough subsides within two to three weeks after the illness. However, if your cough extends beyond eight weeks, consulting a healthcare provider is advisable. Should you experience additional symptoms like fever, shortness of breath, bloody sputum, or unexplained weight loss, early medical intervention becomes crucial. Experts specializing in chronic cough emphasize that a cough persisting eight weeks or more indicates a condition that now warrants treatment.
