HANDOUT V - 2 - F - Basic handout on immunization

Vaccines are special "medicines" which if administered properly, can prevent some diseases. We call this process immunization.

Immunization: Immunity and antibodies

If you hat whooping cough as a child, you only contracted it once because your body became immune to it. The body produces certain antibodies which are special proteins found in the blood. These antibodies fight the organisms that cause disease or the toxins (poisons) that organisms make. antibodies attach themselves to an organism and kill it off or they attach themselves to toxins and sop weak from causing harm. The antibodies which fight toxins are called antitoxins. A different kind fights antibody fights each organism or toxin. For example, measles antibodies only fight the measles virus, they have no effect on malaria. Antitoxins against tetanus are not helpful against diphtheria.

While a child is ill with measles, the body begins to produce the special antibody against the measles virus. The body continues making this antibody, thus the child becomes immune and never has measles again. When the body makes its own antibodies, it has an active immunity. The body becomes actively immune in two ways, either from the disease it self or from a vaccine. These vaccines are grown from harmful organisms and either killed (dead vaccines), or made weak (live vaccines). Because the organisms in a vaccine are weak or dead, they cause no harm beyond what may be milt symptoms (such as a mild fever). When the vaccine is given, the body produces antibodies against the particular organisms thus preventing the body from becoming ill from the disease it self. When disease makes the body immune, it has a natural active immunity. If vaccine la given to make the body immune, it has an artificial active immunity.

Active immunity la the beat kind because it alloys thee body to continue producing its own antibodies. The only problem is that it may take several weeks or longer before the body becomes immune. If necessary, the body can be me de immune immediately by injecting antibodies from another person or animal. These antibodies give the body a passive immunity for a relatively short period of time (usually about two weeks).

The body can receive natural passive immunity while still in the mothers uterus. The antibodies ant antitoxins are present in the mothers blood and are passed to the child's blood before birth. At birth the child is immune to the same diseases as the mother.

Natural passive immunity explains why children do not usually have certain diseases until they are about three months oft. By this age, most of the antibodies they were given at birth from their mothers have gone. By injecting- new antibodies from an immune person or animal, we can give the body an artificial passive immunity. For example, we can inject tetanus antitoxin into an injured person who might have tetanus bacteria in his wound. The antitoxin makes the body immune immediately, before the body has had time to make Its own antitoxin. The injected antibodies or antitoxin are soon destroyed, giving the body artificial passive immunity for not more than a couple weeks.

It is important to remember that live vaccines die easily and become useless. Therefore, care must be taken in the transport and storage of such vaccines. The same is true of dead vaccines but to a lesser extent.

Example a of live and dead vaccines.

Live vaccines	Dead vaccines
BCG (against T.B. )	Diphtheria
Polio	Whooping cough
Measles	Tetanus
	Tetanus toxoid

Some Common Immunizations Given to Peace Corps Volunteers

NOTE This is meant to be a representative flat of some of the most frequently used immunizations The actual selection may vary from one volunteer to another and from one country to another, depending on regional considerations, local governmental guidelines ant chancing circumstances. For examples a local outbreak of measles or cholera might mean immunizations for everyone. It la the responsibility for each volunteer to make sure that his/her immunization records are kept up- to- date during Peace Corps service

TYPE	VACCINE LlVE/DEAD	IMMUNITY ACTIVE/PASSIVE	TIMETABLE
Yellow Fever	Live	Active	10 years
Diphtheria Tetanus	Dead	Active	Booster
Cholera	Dead	Active	6 months
Gamma Globulin	Dead	Passive	3- 6 months
Rabies	Dead	Active	2 years
Polio	Live	Active	Booster
Typhoid Fever	Dead	Active	1 in USA -
			1- one month later
			1- three years later