Immunization is a process used to initiate or augment resistance to infectious diseases. The ultimate goal is to prevent, and in some cases eradicate, potentially serious, life-threatening diseases.

The immune response protects the body against disease.

Immunization (vaccination) is a means of triggering acquired immunity. This is a specialized form of immunity that provides long-lasting protection against specific antigens which can cause certain diseases. This works because the immune system can learn to recognize dangerous invaders if they are presented to it in a weakened form.

In immunization, small doses of the antigen (such as dead or weakened live viruses) are given to activate the immune system. When the immune system comes in contact with the antigens, it learns how to attack them and remembers what they look like. This allows the body to react quickly and efficiently when faced with the actual disease-causing organism. Immunization is one of the best means to protect against many contagious diseases.

Four different types of vaccines are currently available.

• Attenuated (weakened) live virus is used in the measles, mumps, and rubella (MMR) vaccine and the varicella (chicken pox) vaccine. These vaccines last longer than other vaccines, but may cause serious infections in people with compromised immune systems.
• Killed (inactivated) viruses or bacteria used in some vaccines. For example, the influenza vaccine uses killed virus. These vaccines are safe, even in people with compromised immune systems.
• Toxoid vaccines contain a toxin produced by the bacterium or virus. For example, the diphtheria and tetanus vaccines are actually toxoids.
• Biosynthetic vaccines contain synthetic "man-made" substances which appear to be antigens to the immune system. For example, the Hib (Haemophilus influenzae type B) conjugate vaccine is a biosynthetic vaccine.
  

IMMUNIZATION SCHEDULE
The recommended schedule of immunizations is updated yearly by organizations such as the American Academy of Pediatrics (AAP). Consult your primary health care provider about the specific immunizations needed. The current recommendations are available at the Centers for Disease Control & Prevention (CDC) website.

EXPLANATION OF VACCINE ABBREVIATIONS

• HBV: Hepatitis B vaccine (3 total doses recommended).

• Polio: Inactivated polio vaccine (4 total doses recommended).

• DTaP: Diphtheria/tetanus/acellular pertussis (3-in-1 vaccine; 5 total doses recommended).

• Hib: Haemophilus influenzae type b conjugate vaccine (4 total doses recommended).

• Conjugate pneumococcal vaccine (Prevnar): Protects against certain types of Streptococcus pneumoniae bacteria (3 total doses recommended in most cases).
• Polysaccharide pneumococcal vaccine: for people over age 2 with specific risk factors (see polysaccharide pneumoccal vaccine).

• MMR:Measles/mumps/rubella (3-in-1 vaccine; 2 total doses recommended). See MMR immunization (vaccine).

• Td: Adult tetanus/diphtheria (2-in-1 vaccine; for use in people over age 7). See Td vaccine.
• Influenza (flu) vaccine (for people over 6 months of age)

WHERE AVAILABLE
Immunizations can be provided by the primary health care provider. State or city health departments may also provides immunizations, sometimes at lower cost than when obtained at the primary health care provider's office.

TIPS FOR PARENTS
All of the current immunizations must be given as an injection (shot).

To make this experience easier for the child:

• Tell an older child what is going to happen. Explain that the injection is needed to keep the child safe and healthy. Knowing ahead of time what to expect may be reassuring for the child.
• Explain to the child that it is OK to cry, but suggest that the child try to be brave. Some children are reassured if the parent explains that they do not like injections either, but they try to be brave. Praise the child after the injection is over, whether or not he or she cries.
• Distraction at the moment of the injection is helpful. For example, have the child look away (perhaps at a picture on the wall), have them count or say their "ABCs" or tell them something funny at the time of the injection.
• Try to be calm. The child will notice if the parent cringes before the shot!

Plan something fun for after the injection. A trip to the park or playground, eating out, playing with the child, or other entertainment after the injection can make the next immunization experience less fearful.

IMMUNIZATIONS FOR TRAVEL
The Centers for Disease Control and Prevention (CDC) website provides detailed information for travellers regarding immunization and prophylaxis based on itinerary. Many immunizations should be obtained at least a month before travel.

Remember to take your immunization records with you when you travel internationally.

Because of the enhanced health risks for the international traveler, it is essential that personal health be maintained at an optimal level, health problems be considered in advance, and appropriate medications and medical records be carried with the traveler.

Travelers should try to be aware in advance of when, where, and what type of health care should be sought -- and where to obtain it -- if the need arises.

Rabies vaccine may be necessary if bitten by an animal that is proven rabid, possibly rabid, or in which rabies immunity cannot be proven; or if traveling to an area where rabies is common.

Occupations at higher risk include hunters, forest rangers, taxidermists, laboratory workers, stock breeders, slaughter house workers, veterinarians, and spelunkers (cave explorers).

See also:
Immunization - diptheria
Immunization - pertussis
Immunization - polio
Immunization - tetanus