Vaccination

NATURALLY ACQUIRED IMMUNITY Active: Acquired through contact with microorganisms (infection). Provides long term protection. Passive: Antibodies pass from mother to fetus across placenta or in breast milk (IgG, IgA) Provides immediate short term protection (few months)

ARTIFICIALLY ACQUIRED IMMUNITY Active: Antigens introduced through vaccination. Provides long term protection. Passive: Induced by the transfer of antibodies. Referred to as: Immune serum globulins(ISG), immune globulins (IG) or gamma globulins Provides immediate short term protection

immunity adaptive natural active passive artificial active passive innate

 It was recognized long ago that individuals who survived smallpox, plague, and cholera rarely contracted the disease again.  The terms vaccine and vaccination are derived from vaccinia virus (smallpox of the cow) developed by Edward Jenner in  Vaccine: Is a nonpathogenic immunogen that, when inoculated into a host, induces protective immunity against a specific pathogen. A vaccine is antigenic but not pathogenic.

N Types of Vaccines:  Active vaccine: Microbes, or microbial antigens (capsular proteins, toxins,…..) administrated to produce humoral and\or cellular immune response. long or permanent protection.  Passive vaccine: Protection transferred from another person or animal. Temporal protection that wanes with time.

Properties of active vaccines :  Induce effective protection without significant danger of disease or severe side effects.  Must be able to stimulate cellular and humoral (neutralizing antibodies) immunity against specific pathogen.  Induce long-standing protection.  Inexpensive, and easy to produce.  Stable for storage, transport, and use.

Control of vaccination procedure: Factors that should be considered in immunization procedure: o Pathogenic dose. o Form (type) of vaccine. o Site of administration. o Individuals age. o Individuals immunity.

Types of vaccines  Live vaccines  Attenuated Vaccine  Killed \Inactivated Vaccines  Toxoid Vaccine  Subunit Vaccine

 Live vaccines o Made from living infectious agents without any amendment. not pathogenic but immunogenic. o Example : o small pox vaccine, made of live vaccinia cow-pox virus (not variola virus) which gives cross immunity for variola. o Measles.

Attenuated Vaccine: living microbes but have their virulence weakened by heat or chemicals so the immune response is similar to natural infection.  Should not be given to immunocompromised.  Example: Viruses: oral Polio vaccine, Bacterial: BCG.

 Killed \Inactivated Vaccines: dead or inactivated microbes by physical or chemical treatment. Lost it’s virulence but still immunogenic. Example: Viral: hepatitis A. Bacterial: pertussis.

 Toxoid Vaccine: Detoxified (inactivated) bacterial toxins by formalin or heat. Examples: Diphtheria and Tetanus (DTP).

N  Subunit Vaccine: Bacterial: Capsular material: H.influenzae type b, pneumococci, meningococci. Viral: capsid: surface antigen of Hepatitis B virus (derived from the plasma of infected persons)  Recombinant Vaccine: Genetically modified microbes with low virulence. HBV vaccine (yeast derived).

incomplete forms of HBV (surface antigen)

Adjuvants (aid): - Bacterial components or other substances (chemical), suspended in oil that administrated together with vaccines to increase the effectiveness of immunization. Examples: - The pertussis component of DTP vaccine. - Aluminum phosphate or hydroxide.

Conjugate Vaccine o Conjugation is the process of linking polysaccharide antigen to a protein carrier in order to provoke stronger immune response. o These vaccines are protective even in children under two years of age. o H. influenzae, N.meningitidis, S. pneumoniae.

Carrier protein Polysaccharide linked to carrier protein Conjugate vaccine Bacteria Polysaccharide Conjugation

Immunization schedule in KSA.

Examples of Vaccines Polio: attenuated: administrated orally. Inactivated: administrated Intramuscular. DTP (DTaP): Intramuscular. -Diphtheria: toxoid -Tetanus: toxoid. -Pertussis: killed. acellular pertussis: subunit MMR: Live attenuated Subcutaneous. -Measles. -Mumps. -Rubella. Hepatitis B: Recombinant or subunit IM.

Succesfull Vaccination Projects SMALLPOX Vaccination WHO ( ) Last naturally acquired case SOMALIA last death Global eradication 1979

Afghanistan, Nigeria and Pakistan