Female Speaker: Here at New York's Central Park Wildlife Center, kids are taught about the unique ways in which animals have adapted and evolved to survive in their surroundings. They're not alone. Humans have created their own ways of adapting to the elements. One of the major advances has been the ability to adapt to the world of viruses and bacteria. The creation of antibiotics and vaccines is credited with adding 35 years to the average human life span. The key is beginning the battle against illnesses early. David approaches the world with curiosity and a lack of fear. He already has the advantage of some increased defenses. Jana Lentzner: David has received all of the normal and regular immunizations the rubella mumps, and measles, and also the varicella chickenpox vaccine. Female Speaker: Dr. Larry Pickering is Director of the Center for Pediatric Research in Norfolk, Virginia. Dr. Pickering: Hello! How are you today? Female Speaker: He is also current editor of the Red Book, the American Academy of Pediatrics' report on infectious diseases. He considers children like David fortunate. Many of the illnesses that are preventable today once took a great toll on children in the United States. The statistics are startling. Dr. Larry Pickering: Number one is the age of people who died, because you often times saw six months old, one month old, one year old. And they died from whooping cough, and they died from diphtheria, and they died from polio, and they died from haemophilus influenzae, which is a bacteria that causes brain infections. And when you look at national statistics, hundreds of thousands of people contracted these diseases in the early 1900's. We don't see these diseases anymore. Female Speaker: In the 1920's, vaccines were created to help control pertussis, diphtheria and tetanus. These evolved and were combined into the modern day DTaP shots. Diphtheria makes it hard or impossible to swallow or breathe. Tetanus, a germ that gets through the skin and attacks the nervous system, can also be deadly. Pertussis known as whooping cough causes violent spells of coughing, which can make it hard for a child to eat, drink, or even breathe. It can lead to pneumonia, convulsions, even death. Another major illness polio would make headlines when epidemics in the 1940's and 50's crippled, paralyzed, and killed thousands of Americans. In 1955, the first injectable polio vaccine, an inactivated virus was discovered by Dr. Jonas Salk. In 1961, a live oral polio vaccine was discovered by Dr. Albert Sabin. The vaccines virtually eradicated the disease in the Western Hemisphere. Beginning in 1964, vaccines for measles, mumps and rubella were created. These became known as the MMR vaccine. Measles causes a rash, high fever and can also cause pneumonia, deafness, brain damage and death. Mumps causes painful swelling of the glands and can inflame the brain or the spinal cord. Rubella, or German measles, is a mild illness for children. But pregnant women who get it may lose their babies, or give birth to children who suffer from cataracts, glaucoma, deafness or even heart and brain defects. In 1990, the Haemophilus Influenzae Type B vaccine known as HIB began saving thousands of lives. In the United States, it virtually eradicated a once common type of meningitis.