At birth, children have a natural immunity to some diseases. Those who are breastfed receive added protection through their mother's milk. But infants natural defenses last only a few months. After that, they require outside help to fight off diseases.

  Fortunately, you can protect your child from many dangerous childhood diseases by adhering to a proper schedule of immunizations. When your child is immunized against disease, his or her body produces antibodies that can ward off infection. Many states require that children be immunized before enrollment in a licensed day care center or school. This means some children dont get immunizations until they enter school at 5 or 6 years old. In fact, the Centers for Disease Control and Prevention estimate that 40 to 50 percent of children younger than 2 have not completed the recommended immunization schedule and are being exposed to unnecessary health risks.

  Childhood immunizations are recommended for 11 different diseases. If your child hasn't received immunizations on schedule, be sure to schedule an appointment with your pediatrician as soon as possible. 

  Immunizations are among the most vital and cost-effective steps you can take to assure that your child remains healthy. While there is a small risk associated with immunizations, it is much smaller than the risk of not being immunized. If you have any questions about immunization, be sure to speak to your physician.

  Most parents have no qualms about it, said Aimee Christian, MD, a Memphis pediatrician. They want their kids to be immunized, because they protect them from so many diseases.

  When Christian was a pediatric resident, the vaccine for Haemophilus influezae type B, which can cause meningitis, a potentially fatal infection of the brain and spinal cord, had not been approved for children younger than 2. (It was approved for infants in 1990.) Before the vaccine, the peak incidence of H-flu meningitis occurred at 15 months old. Now it is 25 years old.

  We saw cases of H-flu meningitis in young children. It could be devastating, Christian said. Now pediatric residents dont ever see it unless its in a child who hasnt been immunized.

  Obtaining the full schedule of immunizations can be quite expensive, particularly if you dont have insurance or your insurance doesnt cover the full cost. For lower cost immunizations, contact your local health department. The vaccines there are the same as those in a private physicians office.

  These are the diseases for which children should receive immunizations:

• Measles - A highly contagious, airborne viral disease, measles begins with tearing, a runny nose, coughing and fever. The second stage includes a red rash, higher fever and worsening cough. The infection usually lasts 10 days to two weeks. Measles can lead to ear infections, pneumonia and even encephalitis (inflammation of the covering of the brain and spinal cord). It can cause convulsions, deafness or mental retardation. 
• Mumps - Mumps is an airborne viral infection transmitted by coughing, sneezing and close contact. It usually causes fever, listlessness, headaches and inflamed, painful salivary glands, which make the jaws swell. In adolescent males, it can lead to painful inflammation of the testicles and sterility. The pancreas also may be infected. In some cases, it can lead to complications such as meningitis, encephalitis and, in rare cases, deafness.
• Rubella - Also known as German measles, it is a contagious disease spread by coughing, sneezing and close contact. It begins with a low grade fever, followed by a rash that starts on the face and neck, swelling of the lymph glands, eye irritation, sneezing, coughing and a sore throat. Adolescents may also experience joint pains or inflammation. It usually lasts about three days. A relatively harmless disease in childhood, it can cause miscarriages, birth defects and mental retardation if contracted by a pregnant woman.
• Diphtheria - Easily spread through coughing or sneezing, diphtheria is a life-threatening disease. Early symptoms are a sore throat, headache, slight fever and chills. In some children, a grayish membrane may form on the throat, interfering with swallowing and breathing. Other children may develop skin infections. Untreated, diphtheria can lead to pneumonia, paralysis and heart failure. About one in 10 cases result in death.
• Pertussis - Also known as whooping cough, it is a serious respiratory illness and a highly contagious bacterial infection. Pertussis causes severe coughing spells, and possibly vomiting. It can interfere with a child's ability to breathe, eat or drink and lead to serious complications such as pneumonia. About two out of every 100 cases result in convulsions or more serious complications such as encephalitis. Pertussis is most severe in infants younger than 1.
• Tetanus - Also known as lockjaw, tetanus is a soil-based bacterium that enters the body through cuts, burns, animal bites or scratches. It produces a toxin that attacks the nervous system, causing the muscles of the body to go into spasm. Symptoms include difficulty swallowing, restlessness, irritability and stiffness in the jaws, necks, arms, legs and abdomen. According to the Food and Drug Administration, two or three out of every ten cases of tetanus result in death. 
• Haemophilus Influenzae Type B - A bacterial infection, also known as Hib disease, it can cause a number of infections in children, some quite serious, especially meningitis and epiglottitis. According to the U.S. Department of Health and Human Services, meningitis kills 5 percent of the children who contract Hib. Many other children suffer permanent damage to the nervous system, even mental retardation. Symptoms of meningitis include fever and vomiting, lethargy or unresponsiveness, poor color, a stiff neck, a rash or convulsions.
• Polio - A viral disease, polio is unapparent or mild in 90 to 95 percent of the cases, but in  its severe form permanent paralysis and even death can occur. Paralytic polio's symptoms include a sore throat, fever, headache and vomiting, and sometimes pain and stiffness in the neck, back and legs. These symptoms are followed by the development of paralysis.
• Hepatitis B - Transmitted by the blood and body fluids of infected persons, Hepatitis B may appear at first as a case of the flu, accompanied by fatigue and aches in the muscles and joints. These symptoms may soon be followed by nosebleeds and a tell-tale yellowing of the skin. Hepatitis B is a serious infection that can damage the liver and lead to liver cancer. It can even result in lengthy illness and death.
• Varicella - Varicella, or chickenpox, is one of the most common childhood diseases. It is caused by the varicella-zoster virus. Most people in the United States get chickenpox while they are still children. Until the late 1990s, there were about 4 million cases a year. But now that people are using varicella vaccine that number has begun to drop.
• Pneumococcal disease Pneumococcus is a bacterium that causes everything from ear infections to life-threatening forms of meningitis, bacteremia and pneumonia. The vaccine is very good at preventing severe disease, hospitalization and death. However it is not guaranteed to prevent all symptoms in all people.

  The influenza vaccine is still recommended for children 6-24 months old who attend day care. The Food and Drug Administration recently approved a flu vaccine nasal spray for people ages 5-49 years old.

  The Hepatitis A vaccine is recommended for certain groups. For example, many downtown Memphis day care centers require it because the downtown area has been the site of numerous cases in the past.