Vaccination

immunity

adaptive

natural

active

passive

artificial

active

passiveinnate

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 vaccineso 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 Vaccineo Conjugation is the process of linking

polysaccharide antigen to a protein carrier in order to provoke stronger immune response.

oThese vaccines are protective even in children under two years of age.oH.influenzae, N.meningitidis, S.pneumoniae.

Carrierprotein

Polysaccharide linked to carrier

protein

Conjugate vaccineBacteria

Polysaccharide

Conjugation

Immunization schedule in KSA.

Examples of VaccinesPolio: 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 ( 1967 - 1977 )Last naturally acquired case SOMALIA 19771978 last death Global eradication 1979

Afghanistan, Nigeria and Pakistan