While most people shrug off the common cold as a minor nuisance, a new study highlights how the virus behind it can have severe consequences for those with underlying respiratory conditions. Rhinoviruses, the cause of the common cold, number over 170 known strains. For healthy individuals, they often produce mild or no symptoms. But for people with asthma or chronic obstructive pulmonary disease (COPD), rhinovirus infections can trigger severe flare-ups, causing dangerous breathlessness, coughing, and excessive mucus production.
Research led by scientists at Yale School of Medicine and published in Cell Press Blue shows that the difference in disease severity comes not from the virus itself but from the host’s immune response. Using nasal tissue grown in laboratory dishes, researchers observed how cells react to rhinovirus infection. In healthy tissue, only about 1 percent of cells became infected, yet infected cells released signaling molecules called interferons. These molecules act as an early warning system, activating antiviral defenses in neighboring cells and preventing the virus from spreading.
When the interferon signal was blocked, however, the infection escalated dramatically. Tissue began producing large amounts of mucus and inflammatory signals, mimicking the symptoms seen in asthma and COPD attacks. “The timing really matters,” said Ellen Foxman, an immunobiology professor at Yale. “If the response is delayed enough for the virus to replicate significantly, that’s when severe symptoms emerge.”
Other research supports these findings. Nathan Bartlett, a professor at the University of Newcastle and Hunter Medical Research Institute, noted that cells from airways chronically exposed to inflammation respond more slowly to infection. Even a 24-hour delay can allow the virus to multiply exponentially, leaving the body to contend with a larger viral load and stronger inflammatory response.
The study focused on a subset of nasal cells and did not include specialized immune cells present in a living human nose. Still, it offers critical insight into the cellular signaling that determines whether a rhinovirus infection remains mild or becomes life-threatening for vulnerable patients.
Researchers hope these findings could guide the development of treatments or vaccines aimed at reducing dangerous flare-ups. Bartlett suggested that a universal vaccine stimulating broad immune protection could be particularly beneficial for people with chronic respiratory conditions. “We can bring rhinovirus into the conversation now because it’s probably the virus we’re going to encounter more than anything,” he said.
As cold season approaches, understanding how simple infections can turn severe in at-risk populations could help doctors better protect patients with asthma and COPD and pave the way for interventions that prevent complications before they arise.