Meningitis can be caused by many different infections, most commonly bacteria or viruses.
The bacteria or viruses that cause meningitis often live in parts of the body where they do no harm, so we do not know who is carrying the infection and who is not.
The bacteria responsible for most bacterial meningitis (meningococcal, pneumococcal and Hib) often live in the nose and throat. Research tells us that one of the most common causes of bacterial meningitis, meningococcal bacteria, are harmlessly carried in the back of the nose and throats of around 1 in 10 people.
The bacteria can spread from one person to another by droplets from the nose and mouth, for example, by coughing, sneezing or intimate kissing. They do not spread as easily as infections like flu, but close family members and close friends of someone with meningitis caused by meningococcal bacteria are at increased risk of picking up the infection. You may get ill after picking up the infection, but it is much more usual not to become ill.
Bacteria can spread from one person to another by droplets from the nose and mouth, for example, by coughing in close contact.
Group B streptococcus (GBS) is another type of bacteria that can cause meningitis, especially in newborn babies. These bacteria often live in the vagina and intestines, and they may spread to the baby around the time of birth.
Different viruses can cause meningitis. Some like enteroviruses or coxsackieviruses live in the nose, throat and intestines. They can spread through faecal contamination of hands or surfaces, through droplets from the nose and throat, or from mother to child in pregnancy.
These examples cover the main methods of spread of the many bacteria and viruses that can cause meningitis.
Can you prevent spread of these infections?
It is hard to prevent spread of infection between people without living in total isolation. Antibiotics are recommended for close contacts of people with meningococcal meningitis to stop the spread of the bacteria. This is a short-term solution. Vaccination can provide longer term protection. Some vaccines that protect against illness also prevent the bacteria from spreading from person to person. Vaccines that protect against Hib meningitis, and many that protect against pneumococcal and meningococcal meningitis, also stop the bacteria from living in the nose and throat and so stop the spread to others.
Cigarette smokers are more likely to carry the meningococcal bacteria in their throats, so stopping smoking may be another way to reduce spread of this infection.
Some viruses and bacteria that cause meningitis can also be found in saliva. It is sensible hygiene advice not to share drink bottles, glasses or cups. Good hand hygiene can also helps to prevent the spread of some infections.
Importance of vaccination
There are many types of meningitis and many different ways of spreading infection. The most important thing that anyone to can do to protect themselves and others from meningitis is to make sure they and their loved ones get all their vaccinations. This not only protects the person who gets vaccinated, but also protects the wider population by preventing the spread of the bacteria that cause disease.