Vaccination

immunity adaptive natural active passive artificial active passive innate

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) 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

 It was recognized long ago that individuals who survived smallpox, plague, and cholera rarely contracted the disease again.  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.

The terms vaccine and vaccination are derived from vaccinia virus (smallpox of the cow) developed by Edward Jenner in 1798 Rabies vaccine (developed by Louis Pasteur in 1880).

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

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. Temporary protection that wanes with time.

Control of vaccination procedure: Factors that should be considered in immunization procedure: o Pathogenic dose. o Form 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: small pox vaccine, made of live vaccinia cow-pox virus (not variola virus) which gives cross immunity for variola.

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 (Sabine), 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. Example: Diphtheria and Tetanus.

N  Subunit Vaccine: Bacterial: Capsular material: H.influenzae type b, Pneumococci, Meningococci. Viral: capsid: surface antigen of Hepatitis B virus  Recombinant Vaccine: Genetically modified microbes with low virulence (pathogenic genes are removed). HBV vaccine.

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; Sabine: administrated orally. Inactivated; Salk: administrated Intramuscular. DTP (DTaP): Intramuscular. -Diphtheria: toxoid -Tetanus: toxoid. -Pertussis: killed. acellular pertussis: subunit MMR: Live attenuated Subcutaneous. -Measles. -Mumps. -Rubella. Hepatitis B: Recombinant IM.

SUCCESFULL VACCINATION PROJECTS SMALLPOX Vaccination WHO ( ) Last naturally acquired case SOMALIA last death Global eradication 1979

Afghanistan, Nigeria and Pakistan