Invasive H. flu, or Hib disease, is an infection caused by the Haemophilus influenzae type b (Hib) bacteria, which spreads when an infected person coughs, sneezes or speaks. Invasive H. flu is a bit of a misnomer because it isn't related to any form of the influenza virus. However, it can lead to bacterial meningitis (a potentially fatal brain infection), pneumonia, epiglottitis (severe swelling above the voice box that makes breathing difficult) and infections of the blood, joints, bones and pericardium (the covering of the heart). Children younger than 5 years old are particularly susceptible to the Hib bacteria because they haven't had the chance to develop immunity to it. The first Hib vaccine was licensed in 1985, but despite its success in the developed world, the disease is still prevalent in the developing world. WHO estimates that each year Hib disease causes 2 to 3 million cases of serious illness worldwide, mostly pneumonia and meningitis, and 450,000 deaths of young children. If you're not familiar with diseases like the invasive H. flu, see the next page to read about the cures for more household name diseases such as the measles.