immuniaztion

Immunization
Is a remarkable successful and very cost effective means of preventing infectious diseases.
Vaccination= is administration of any vaccine or toxiod for preventing the diseases
Immunization=is processes of induction of vaccine (active ) or by Ab(passive)
Active=celluler+Ab=long term protection
Passive=temporary protection, by exogenous Abs(IgM)or by Tran placental (natural)=give protection in the 1st several months of life. In general vaccine are indicated at younger age group at which significant risk of diseases and its complication exist and at which protective immune response can be expected

Immunizing agents
Vaccine=preparation of protein, polysaccharide, , or nuclear acid of pathogen. either attenuated (live) or killed M.O to induce specific response that inactivate , destroy, and suppress the pathogen.
Live=MMR, oral polio(Sabin), typhoid ,BCG.
Is more antigenic , looks like natural infection
Killed inactivated)=less antigenic, need booster doses to build good immunity. either whole MO(whole cell pertussis, HAV), detoxified (tetenus and diphtheria), purified protein derivative a cellular type,HBV) , polysaccharide capsular meningococcal vaccine), capsular polysaccharide conjugated to the protein (Hib and pneumococcal )
Toxiod= modified bacterial toxin that had been not toxic but remain had capacity to produce immunity .
Immunoglobulin(Ig)=Ab-containing solution, derived from human blood
Anti-toxin= Ab-containing solution, derived from serum of human or animal after stimulation of sp. Antigen .
Factors affect the response of vaccine
1- Chemical and physical state of Ag
2-The mode of administration of Ag(i.m, s.c, i.d)i.e(parental polio vaccine not induce mucosal Abs (IgA)where the oral polio vaccine are likely to do so.
3- The catabolic rate of Ag
4- Host factor(age, nutrition, gender, preexisting Abs.
5- Genetic determent of host .
6- The presence of high level of maternal Abs in the 1st few months of life and relative immaturity of immune system early in life will impair the initial response of certain vaccine(measles and MMR).
7- 2 types of Ag
A-thymus-dependent Ag =need interaction of B and T lymphocyte to produce immune response and is more immunogenic and can be given in the 1st 2years of life.
B- thymus-independent Ag= generally no need of effect of thymus(T lymphocyte to produce immune response and is less immunogenic and can not be given in the 1st 2years of life
IMMUNOLOGICAL REACTION AFTER VACCINE
Serum Abs can be detected after 7-10 days(IgM) then replaced by IgG, the secondary immune response become strong and heightened in 4-5days

BCG(BACELLI-CALLMETTE-GUERINE)
BCG vaccine is a lyophilized preparation of live, attenuated organisms of the Calmette-Guérin strain of Mycobacterium bovis that is used to stimulate active immunity to tuberculosis.
In developing countries where tuberculosis is epidemic and short-term prophylaxis with ant tuberculosis agents (e.g., isoniazid) or tuberculin skin test screening is not possible, BCG vaccine is used routinely to attempt tuberculosis control. The World Health Organization currently recommends that BCG vaccine be administered by intradermal injection in the left deltoid region), and can be given in any time during infancy. and give protection for about 5-7years.
(it prevent military TB, and TB meningitis in about 50-80%and pulmory TB in about 50%)

NATURAL HISTORY
The lesion is characterized by a small red papule at the site of injection; the papule reaches its maximum diameter of approximately 8 mm within 5 weeks after administration of the vaccine. The top of the papule scales, ulcerates, and dries, and the entire lesion gradually shrinks to a smooth or scaly pink or bluish scar approximately 3 months following immunization; the lesion then becomes a smooth or pitted white scar in approximately 6 months.