Catching it

Meningococcal disease is caused by bacteria (not by a virus), and transmitted via saliva. Meningococcal bacteria can live harmlessly in our throat and nose. Around 20% percent of people will be carrying these bacteria at any one time without ever becoming ill (‘healthy carriers’). In fact, all of us will carry them at some stage in our lives.

The bacteria are spread by activities such as sneezing, coughing, intimate kissing, and sharing food or drinks. Environments where people are in close contact, such as day-care centres, school camps, parties and nightclubs, make it easier for the bacteria to spread. At nightclubs, there's a risky combination of crowding, smoking, kissing, sharing drinks and shouting above the noise, which can disperse tiny droplets into the air that can be breathed in by someone close by.

However the bacteria only live for a short time outside the body – and even if you them up, it doesn’t mean you’ll become ill. The danger only occurs if you pick up a strain you’re not immunised against, or don’t have any natural immunity to –- or if your immune system has for some reason become weakened and cannot cope.

Who’s at risk

Meningococcal disease can strike both children and adults – anywhere, at any time. But those most at risk are:

• Babies and children up to the age of 5 years – this group accounts for two thirds of cases (due to their less mature immune system and tendency to put things in their mouth and share food, drink and toys).

• Teenagers and young adults from 15 to 25 years – primarily because of the socially interactive lifestyle they lead, which is more likely to involve intimate activities such as kissing and sharing drinks.

• Smoking and passive smoking – can increase the risk of infection.

• Winter and early spring – are higher risk times, because the many viruses around can weaken the body’s natural immune system. There's also the risk of catching a virus first, followed a few days later by a meningococcal infection, making the illness much harder to identify.