Pneumococcal disease is an illness caused by certain germs (bacteria), called Streptococcus pneumoniae. These germs can cause serious infections in the ears, nose, lungs, blood, or brain. Some people have a higher risk of getting pneumococcal disease. This includes people with conditions such as diabetes, heart disease, kidney disease, liver disease, and lung disease. Vaccines help the body fight infections due to diseases like pneumococcal disease, and may help prevent serious illness. New vaccines must be tested to show that they work.