Someone at home has a hacking, chesty cough that has dragged on for days, and the doctor has used the word bronchitis. Now everyone else in the house is asking the same question: can we catch it? Do we need to keep the kids away? Is it safe to hug the baby?
The answer depends on what kind of bronchitis it is, and what is causing it. The short version is that acute bronchitis is usually caused by a virus that can spread from person to person, while chronic bronchitis is not contagious at all. But there is more to it than that, and a few common myths to clear up. This guide explains who can pass bronchitis on, when, and how, with specific answers for babies, people with asthma, kissing and even the family dog.
Overview of bronchitis
Bronchitis is inflammation of the bronchial tubes, the large airways that carry air into your lungs. When the lining of these tubes becomes inflamed and swollen, it produces extra mucus, and the airways narrow. The result is a cough, often with phlegm, along with chest soreness and sometimes wheezing and tiredness.
It is one of the most common chest infections in New Zealand, especially in winter, and in most people it clears up by itself within a few weeks.
Importance of understanding contagion
Knowing whether an illness is contagious matters for the people around you. Being clear about how bronchitis spreads helps you protect babies, older relatives and anyone with a chronic health condition, and it helps you decide when to stay home, without needlessly isolating yourself or worrying about people who are not at risk. If you want to learn more about what different coughs may mean, our guide How to decipher your cough? is a useful read.
What is bronchitis?
There are two main types, and the difference matters when it comes to contagion.
Acute bronchitis
Acute bronchitis is a short term illness, usually following a cold, flu or other viral infection. The viruses that cause it are the same ones that cause colds and flu, which is why it is often called viral bronchitis. Occasionally, bacteria are responsible. It can also be triggered by irritants such as smoke, dust and fumes.
Most cases last one to three weeks, although the cough can linger for longer after the other symptoms have gone.
Chronic bronchitis
Chronic bronchitis is a long term condition in which the airways stay inflamed and produce mucus. It is defined as a cough with phlegm on most days for at least three months in two years in a row. It is a form of chronic obstructive pulmonary disease (COPD) and is mainly caused by smoking, though air pollution and workplace dust and fumes can contribute.
Symptoms of bronchitis
The symptoms of bronchitis include:
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A cough that starts dry, then brings up clear, white, yellow or green mucus
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Chest soreness or tightness
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Wheezing or a whistling sound when breathing
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Mild shortness of breath
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A low fever and chills (a high fever is less typical)
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Tiredness and aches
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A sore throat and blocked or runny nose at the start
Symptoms of chronic bronchitis include a daily cough with mucus, breathlessness and frequent chest infections, which flare in winter. If you want to understand mucus better, see What's s...not? A cough that lasts more than three weeks, or comes with breathlessness, chest pain or blood in the phlegm, should be checked by a doctor.
Is bronchitis contagious?
The most accurate answer is: it depends on the type and cause.
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Acute bronchitis caused by a virus: the infection is contagious. The viruses that cause it can pass from person to person.
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Acute bronchitis caused by irritants (such as smoke): not contagious.
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Acute bronchitis caused by bacteria: can be contagious, but this is much less common.
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Chronic bronchitis: not contagious. It is a long term condition caused by damage to the airways, not an infection you can catch.
There is a subtle point worth understanding. When someone passes on the virus that caused their bronchitis, the person who catches it will not necessarily develop bronchitis. They might just get a cold, a sore throat or a mild cough, or not feel sick at all. Whether the infection travels down to the large airways depends on the virus, the person's immune system, whether they smoke, and whether they have other lung conditions.
Transmission mechanisms
Viral bronchitis spreads in the same ways as colds and flu:
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Droplets. When someone coughs, sneezes or talks, they release tiny droplets containing virus. If you are close by, you can breathe them in.
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Contact with surfaces. The virus can survive on surfaces like door handles, phones, toys and benches. If you touch these surfaces and then touch your eyes, nose or mouth, you can become infected.
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Close contact. Hugging, shaking hands and sharing cups, cutlery or towels all spread germs.
How long are you contagious? People with viral bronchitis are usually most contagious in the first few days of illness, when they have a fever, runny nose and a lot of coughing, and often from a day or so before symptoms appear. Many people are much less infectious after about a week, even if a cough lingers. As a practical guide, stay home while you have a fever or feel unwell, and take extra care to avoid contact with babies, older people and anyone with a weakened immune system until you are clearly on the mend.
A lingering cough does not necessarily mean you are still contagious. The airways can stay sensitive and irritated for weeks after the infection has gone.
Virus vs bacteria
Most acute bronchitis is caused by viruses, and so antibiotics do not help. Bacteria are a less common cause. Certain bacteria can cause bronchitis like illness and are contagious, for example whooping cough (pertussis), which causes severe coughing fits and can be serious in babies, and some atypical bacteria. If you or your child have coughing fits that end in vomiting, gasping or a "whoop," or a cough that is lasting and worsening, see a doctor.
Coloured phlegm does not tell you whether an infection is viral or bacterial. Yellow or green mucus is common in viral bronchitis and does not by itself mean you are more contagious, or need antibiotics.
Is bronchitis contagious in NZ?
The question "is bronchitis contagious NZ" has the same answer as anywhere else in the world: viral bronchitis can spread, and chronic bronchitis cannot. What is particular to New Zealand is the timing and the setting. Chest infections peak in the cooler months, from autumn through winter and into early spring, when people spend more time indoors, schools and childcare centres spread viruses easily, and cold, damp housing can make coughs worse.
Practical advice for New Zealand families:
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Stay home when unwell. Ring in sick, and keep sick children away from school or childcare until they have recovered and are feeling better. Follow the guidance from your school or centre.
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Get the annual flu vaccine if you are eligible. It is free for some groups, so ask your GP or pharmacist.
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Keep your home warm, dry and well ventilated.
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Call Healthline on 0800 611 116 for free advice, 24 hours a day.
For seasonal tips, see How to beat the winter bugs and Preparing for the colder months ahead.
Is asthmatic bronchitis contagious?
"Asthmatic bronchitis" is not a formal medical diagnosis, but people use the term for bronchitis in someone with asthma, or for asthma flare ups triggered by a bronchial infection. Here, there are two parts to consider:
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Asthma itself is not contagious. It is a long term condition of the airways, and you cannot catch it from someone.
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The infection that triggers a flare can be contagious. If a virus is causing the bronchitis, it can spread to others, just like any cold or flu virus.
People with asthma are more likely to have a bad reaction to chest infections, so they should take extra precautions, follow their asthma action plan, and see a doctor if they have worsening cough, wheeze or breathlessness. Call 111 if breathing is severe.
Is bronchitis contagious to babies?
Yes, the viruses that cause bronchitis in adults can spread to babies, and this is where the concern is greatest. A virus that gives an adult a cough and chest cold can cause bronchiolitis or pneumonia in a young baby, because their airways are tiny and their immune systems are still developing. Newborns and babies under three months are at highest risk.
If you or someone in your home has bronchitis or a chesty cough:
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Keep the baby away from the person who is unwell, if you can, especially in the first days of illness
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Wash hands thoroughly before touching or feeding the baby
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Cough and sneeze into your elbow or a tissue, away from the baby
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Avoid kissing the baby on the face or hands
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Do not share cups, bottles or dummies
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Keep the home smokefree
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Ask unwell visitors to postpone their visit
Seek help promptly if a baby develops a cough, fast breathing, feeding trouble or a fever. Any baby under three months who is unwell should be seen by a doctor. Call 111 for blue or grey lips, pauses in breathing, or if they are floppy or very hard to wake. Our guide Keeping Your Children Healthy During Cold and Flu Season has more information for families.
Is bronchitis contagious in dogs?
Dogs can develop bronchitis too, and the answer is similar, with some differences:
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Infectious tracheobronchitis (K-9 cough) is a contagious airway infection in dogs, caused by a mix of viruses and bacteria. It spreads easily between dogs in kennels, daycare and parks, through droplets and shared bowls. Vaccination is available, and your vet can advise.
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Chronic bronchitis in dogs is a long term inflammation of the airways and is not contagious.
The viruses and bacteria that cause bronchitis in dogs generally do not spread to people, and human bronchitis viruses do not usually affect dogs, though in rare cases, some bacteria involved in kennel cough can affect people with weakened immune systems. If your dog has a persistent cough, take it to a vet. If you have a weakened immune system, ask your doctor for advice.
Misconceptions about Bronchitis
Is Bronchitis Contagious through Kissing?
Yes, if the bronchitis is caused by a contagious virus, kissing can spread it. The viruses are present in saliva and respiratory droplets, and kissing involves close face to face contact. It is not the kissing itself that is special, but the proximity. If your partner has acute bronchitis, you may want to avoid kissing while they have a fever, are coughing heavily or are in the first week of the illness, and wash your hands often. Chronic bronchitis cannot be spread by kissing. Kissing babies is best avoided if anyone in the household is unwell.
Common Myths
Myth: All bronchitis is contagious. Fact: Chronic bronchitis and bronchitis caused by irritants cannot be caught from another person.
Myth: You are contagious as long as you are coughing. Fact: A cough often lingers for weeks after you are no longer infectious.
Myth: Yellow or green phlegm means it is contagious or needs antibiotics. Fact: Phlegm colour is not a reliable guide. Most bronchitis is viral and does not need antibiotics.
Myth: You can catch bronchitis from being cold or wet. Fact: Cold weather does not cause infection. You need to be exposed to a virus. Winter does, however, increase close indoor contact and the spread of viruses.
Myth: Antibiotics will stop it from spreading. Fact: Antibiotics do not work against viruses and do not make you less contagious.
Myth: If you have had bronchitis, you cannot get it again. Fact: Many different viruses cause it, so you can have it more than once.
recap of key points
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Acute bronchitis is usually caused by a contagious virus, but the person who catches it may only develop a cold
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Chronic bronchitis is not contagious
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Viral bronchitis spreads through droplets, close contact and contaminated surfaces, mostly in the first week
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A lingering cough does not always mean you are still infectious
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Babies are most at risk of becoming seriously unwell from viruses spread by others
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Asthma is not contagious, but the infections that trigger flare ups can be
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Kissing can spread viral bronchitis, and kennel cough is contagious between dogs
recommendations for prevention
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Wash your hands with soap and water often, especially before eating and after coughing or sneezing
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Cover coughs and sneezes with your elbow or a tissue, and bin tissues straight away
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Stay home when unwell, and keep sick children home
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Do not share cups, cutlery, towels or toothbrushes
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Clean shared surfaces like door handles, phones and toys regularly
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Get vaccinated. The annual flu vaccine helps prevent flu and its complications. Ask your GP about COVID-19 and other vaccines.
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Keep your home smoke-free. Quitline (0800 778 778) offers free support.
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Keep rooms ventilated and avoid crowds when infections are going around
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Protect those at risk, including babies, older adults and people with chronic conditions
See a doctor if your cough lasts more than three weeks, you have a lasting fever, breathlessness or chest pain, or you are worried. Healthline (0800 611 116) is free and open 24 hours a day, and 111 is for emergencies. For help getting back on your feet, read From Sickness To Recovery.
Frequently asked questions
Question: Is bronchitis contagious?
Short answer: Acute bronchitis caused by a virus can be contagious, because the virus can spread to others, though they might only develop a cold. Chronic bronchitis is not contagious.
Question: How long is bronchitis contagious for?
Short answer: Viral bronchitis is usually most contagious in the first few days, and often for about a week. A cough can linger much longer without you being infectious. Stay home while you have a fever or feel unwell.
Question: Is bronchitis contagious in NZ?
Short answer: Yes, acute viral bronchitis spreads in New Zealand the same way as elsewhere, and it is most common in winter. Stay home when unwell and keep sick children away from school or childcare until they are better.
Question: Is asthmatic bronchitis contagious?
Short answer: Asthma itself is not contagious, but a virus triggering bronchitis in someone with asthma can spread to others. People with asthma should follow their action plan and see a doctor if symptoms worsen.
Question: Is bronchitis contagious to babies?
Short answer: Yes. The viruses that cause bronchitis can spread to babies and may cause serious illness such as bronchiolitis. Keep unwell people away from babies, wash hands and avoid kissing. Seek help promptly if a baby has a cough or breathing difficulties.
Question: Is bronchitis contagious in dogs?
Short answer: Kennel cough is a contagious airway infection between dogs. Chronic bronchitis in dogs is not contagious. Dog respiratory infections do not usually spread to people, but see a vet for any persistent cough.
Question: Is bronchitis contagious through kissing?
Short answer: If it is caused by a contagious virus, yes. Avoid kissing while the person has a fever, heavy cough or is in the first week of illness. Chronic bronchitis cannot be spread by kissing.
Question: What are the symptoms of bronchitis?
Short answer: A cough (dry, then with phlegm), chest soreness or tightness, wheezing, mild breathlessness, tiredness, a low fever and a sore throat. See a doctor if it lasts more than three weeks.