Bronchitis is an inflammation of the bronchial tubes, the main airways that carry air into the lungs. This irritation causes the airways to swell and produce excess mucus, leading to the hallmark symptom of a persistent cough. Whether this condition can be caught from another person depends entirely on the underlying cause of the inflammation.
The Distinction: Contagious vs. Non-Contagious Bronchitis
Bronchitis is categorized into two main types: acute and chronic. Acute bronchitis is a short-term illness, often developing after a cold or flu, and is the form that is typically contagious. This temporary inflammation usually lasts one to three weeks, though the associated cough can linger for several weeks.
Chronic bronchitis is defined by a productive cough that persists for at least three months of the year for two or more consecutive years. This long-term condition is not caused by an infectious agent, but rather by sustained irritation to the airways, most commonly from cigarette smoke or environmental pollutants. Chronic bronchitis is a non-transmissible illness, meaning it cannot be caught from another person.
Identifying the Underlying Cause
The contagiousness of acute bronchitis stems from the infectious agents that trigger it. The vast majority of acute bronchitis cases (85% to 95% in healthy adults) are caused by viruses. These viruses are often the same ones that cause the common cold (such as rhinovirus and adenovirus) or the flu (influenza A and B).
A smaller percentage of cases are caused by bacteria, including organisms like Mycoplasma pneumoniae or Bordetella pertussis (whooping cough). Because the cause is overwhelmingly viral, antibiotic medications are ineffective for most cases of acute bronchitis. Antibiotics are only useful when a bacterial infection is confirmed.
How Acute Bronchitis Spreads
Acute bronchitis spreads because the viruses and bacteria that cause it are highly contagious. The pathogens are transmitted primarily through respiratory droplets released when an infected person coughs, sneezes, talks, or breathes. If a person is in close proximity, they can breathe in these airborne droplets and become infected.
Infection can also occur through indirect contact with contaminated surfaces. An infected person may transfer the virus to surfaces like doorknobs, phones, or countertops. If an uninfected person touches these surfaces and then touches their mouth, nose, or eyes, the pathogen can enter their body. The contagious period for viral bronchitis is typically a few days up to a week, with people being most contagious in the initial days of the illness.
Preventing Transmission
Taking proactive steps can significantly reduce the risk of contracting the infectious agents that cause acute bronchitis. Frequent and thorough hand washing with soap and water is the most effective preventative measure. If soap is unavailable, an alcohol-based hand sanitizer can be used.
Covering the mouth and nose when coughing or sneezing, ideally with a tissue or the elbow, helps contain respiratory droplets. It is also helpful to avoid touching the face, particularly the eyes, nose, and mouth, to prevent transferring germs into the body. Staying current on vaccinations, such as the annual flu shot, is a practical way to prevent some of the most common viral causes of acute bronchitis.