Immunization prevents the following serious infections that can cause disease, disability, and death. These diseases used to strike thousands of children each year. Today there are relatively few cases, but outbreaks still occur each year because some babies are not immunized. Except where noted, these diseases spread when viruses or bacteria pass from and infected person to the nose or throat of others. Diphtheria - This serious disease is spread by a bacterium.
Diphtheria can block the airway, making it impossible to breathe.
It can also cause heart problems. Three of 10 people who get tetanus die. It can cause spells of violent coughing and choking, making it hard to breathe, drink, or eat. The cough can last for weeks. Pertussis is most serious for babies, who can get pneumonia, have seizures, become brain damaged, or even die.