- The severity of a cold may hinge on how quickly nasal cells launch an antiviral response, not just the virus itself
- Interferons help nearby cells switch on defences fast – if this response lags, the virus spreads and inflammation rises
- As viral replication grows, separate pathways can trigger mucus and inflammatory signals that worsen breathing symptoms
Two people can catch the same cold virus and have completely different outcomes – one gets a runny nose for a day, the other ends up with heavy congestion and a lingering cough.
Research using lab-grown human nasal tissue suggests the difference may come down to speed: how quickly the nose mounts its first-wave antiviral response.
Rhinovirus is the most common cause of the common cold and is also a frequent trigger for breathing problems in people with asthma and other long-term lung conditions.
The study looked at what happens right at the start of infection, inside the cells lining the nose – before the rest of the immune system has fully joined the fight.
To study that early phase in detail, researchers built an organoid model of human nasal lining.
They grew nasal stem cells for weeks in conditions that encouraged them to form a tissue structure resembling the airway lining, complete with multiple cell types, mucus-producing cells and ciliated cells that help move mucus out.
With this model, they could track how thousands of individual cells responded as infection unfolded.
A key finding was the importance of interferons – proteins that help cells block viral entry and viral replication.
When nasal cells detect rhinovirus, they release interferons that switch on antiviral defences in infected cells and in nearby uninfected cells, creating a coordinated barrier to spread.
When that interferon response kicked in rapidly, the infection could be contained early.
When the researchers blocked the sensing and signalling steps that drive this response, the virus spread far more widely, damaging the tissue and in some cases overwhelming the organoids.
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The study also found that when viral replication ramps up, a different kind of response can dominate – one that drives mucus production and inflammatory signalling across both infected and uninfected cells.
That inflammation may help explain why some colds come with heavy congestion and, for some people, breathing difficulties.
The broader point is that illness severity may be decided less by what rhinovirus is and more by how the airway lining reacts in the opening stages.
That shifts the treatment logic – rather than only aiming to attack the virus, future therapies might focus on strengthening rapid antiviral defences while limiting the inflammatory pathways that make symptoms worse.
