Department of Pediatrics, Faculty of Medicine Universitas Indonesia Dr CiptoMangunkusumo
The immune system is complex system, composed of interactions of various body cells, aims to recognize, differentiate, & eliminate antigen (Ag) which is considered foreign (self vc non self). The immune system consist of non specific and specific barrier. Non spesific barrier is first body defense and activated in a few minutes / hour after infection.
It activates the adaptive immune system in a longer time. It has no specific response and no memory cell. Immune innate / non-specific / natural immune response provides early defense against infection.Specific adaptive / immune immune responses occur thereafter and there is a lymphocyte activation.
The immune response needs initiator, navigator
regulators and acceleratation of pathogenesis of infectious diseases, establish a system of identification and signals called PRR (Pattern recognition receptors) to recognize PAMP (Pathogen-associated molecular pattern).
Specific immune respons is a second body defense, arises a few days after antigen enter the body. The specific properties of specific immune response is, the memory cells has last long - lifetime. Effectiveness increases after contact with antigen. The specific immune response consists of: humoral immune response (B lymphocytes) and cellular immune response (T lymphocytes) which has specific abilities and memory.
The purpose of ideal vaccine is produce the same immune system protection as a natural infection but without causing severe illness and complications, produce long-term immunity,
stopping the spread of infection.
The antigen vaccine with antigen-causing natural infection is more similar. Unfortunately when the protective immune response is getting better but the side effect gets heavier.
‘Herd immunity is a form of immunity that occurs when the vaccination of a significant portion of a population (or herd) provides a measure of protection for individuals who have not developed immunity.’ It applies to diseases that spread from human to human. Each disease has a certain level of immunity in the population
Therefore, a disease can be eradicated even if some people are still vulnerable. It provides indirect protection to unvaccinated individuals such as individuals vaccinated. Example: MMR vaccine is given to infants to protect pregnant women from rubella. Protection in unvaccinated populations occurs when the number of vaccinated individuals cross the threshold. For example the threshold for MMR vaccine is 95%. If lower than that, for example 70% vaccinated, reservoir remains present and outbreaks occur among unvaccinated individuals.
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