January 20, 2026
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Scientists have struggled to understand why the common cold hits some people hard and others mildly. But new research suggests the production of a protein plays a critical role in shaping the body's immune response.
Trying to understand why the common cold hits some people hard – sometimes leading to serious medical complications – but gives other people just the sniffles has been difficult for scientists. But a new study out of Yale Medicine goes part of the way to untangling the mystery.
It's an early immune response in the body rather than the virus itself that causes the cold to be weak or severe, according to the study, published Monday in the journal Cell Press Blue.
"What's clear is that it's not just the virus that determines the disease," said Ellen Foxman, the study's senior author. "There's something about the human body that's really driving the disease outcome, but the mechanisms are not well understood. We set out to understand the mechanisms inside virus-infected cells that push the infection in one direction or another."
To examine this issue, the researchers grew miniature, 3D-tissue structures called organoids from human nasal cells. The organoids acted like actual human noses and lungs, even producing mucus. Then the researchers introduced rhinovirus, the most common cause of colds, to these miniature, nose-like organs in the lab.
They learned that the production of interferons, proteins the body makes to tell the body to fight infections, in the nasal lining work to keep the virus mild. When these interferons are weak or inhibited in some way, the virus becomes more severe and can lead to complications, such as asthma attacks, bronchitis and pneumonia, the study found.
But the researchers still don't know why some people produce sufficient interferons to block rhinovirus and others have a weaker response.
"That's a great question," Foxman said. "In our model, we inhibited the response with a drug, but it's known that in people with chronic airway diseases, the interferon response is lower than in a healthy person. That's the 'why' we just don't know yet. It's our next step."
Rhinovirus spreads through exposure to droplets caused by an infected person coughing or sneezing, as well as physical contact with an infected person.
Symptoms may include nasal congestion, a cough, sneezing, sore throat, headache, mild body aches and fever.
There is no vaccine for rhinovirus. The best defense against rhinovirus is hand washing.
People who experience shortness of breath, wheezing or a high fever for more than three days – or one that returns – should seek medical attention, the Mayo Clinic says.
