It looks like you are using an older version of Internet Explorer which is not supported. We advise that you update your browser to the latest version of Microsoft Edge, or
consider using other browsers such as Chrome, Firefox or Safari.
A cough can be caused by many different things, including:1,2
Some of these causes of cough, like flu3 and the common cold,2 may be contagious (i.e. they can spread from one person to another) whilst other causes, like cigarette smoking or taking regular blood pressure medication, are not. It follows that some coughs may be contagious but others will not be, depending on the cause of the cough.
However, acute cough caused by viral respiratory tract infections is probably the most common illness in humans.5 Infectious respiratory diseases (such as flu or the common cold) can be transmitted to a non-infected person when the infected person coughs and expels droplets (called aerosols) that contain the infectious agent into the environment around them.6
Some pathogens infect us more readily than other pathogens do6 and some people (e.g. children younger than six, smokers and people with a weakened immune system) are more prone to catching infectious conditions than others are.7
Scientists are still learning about how contagious the different cough-causing infections are.8 The type of cough, and the kind of mucus it produces, may have something to do with how contagious it is.9
Scientists fear that there’s little you can do to protect yourself from aerosol particles that can carry an infectious agent. Traditional cough etiquette doesn’t always work: covering your mouth and not coughing directly at people will not necessarily spare them exposure to your bug, particularly if it is a very contagious bug.6 This is why unvaccinated adolescents often catch whooping cough from their friends.10
Better ventilation doesn’t work either.11 Disinfecting hospital air might work,12 and so might the practice of isolated rooms in the hospital setting.13 It seems that particles and bio-aerosols find their way around hospitals and homes almost no matter what.14 Experts are starting to wonder if much of our understanding of cough contagion and prevention is, in fact, an oversimplification.15
The study of environment and infection continues,16 but in the meantime the following tips could help prevent the spread of a contagious cough: