Immunization and vaccination are processes that ensure the active or passive biological resistance of an organism to certain infectious diseases.
Artificial active immunization – stimulation of the immune system by administering a vaccine or toxoid (a neutralized bacterial toxin that retains its antigenic properties). In the case of artificial passive immunization, ready-made antibodies, immunoglobulins, are introduced into the body. The body’s natural active immunization occurs as a result of its infection. The body natural passive immunization occurs when maternal antibodies are transferred to the fetus through the placenta or into the body of a newborn with colostrum. As a result of artificial immunization, highly specific immunity is produced, that is, a vaccine, toxoid or ready-made antibodies give the body partial or complete resistance to the disease.
Vaccines and toxoids protect the body for a long time, sometimes until the end of life. Ready-made antibodies provide only temporary protection; they must be entered again in case of re-infection.
For the first time, vaccinations were practiced to fight smallpox, a disease that had brought deaths to millions of people for centuries. It was noted that people who had suffered from smallpox developed immunity, that is, they did not get sick again. Therefore, the first smallpox vaccination was carried out by the introduction of a small amount of liquid from the bubbles appeared on the skin of patients.
A turning point in the history of vaccination is associated with the name of the English doctor Edward Jenner (1749-1823), who was the first to notice that cowpox infection protects against a truly terrible disease – smallpox.
Jenner injected an eight-year-old boy the liquid from the bubbles on the milkmaid’s hand. As a result, the boy acquired immunity to smallpox. After successful and mass verification of this method, immunization as a means of fighting infectious diseases began to spread everywhere. Thanks to an extensive campaign carried out under the control of the World Health Organization, smallpox has now almost disappeared from our planet.
Advances in immunology have allowed to work out vaccination against many childhood diseases – whooping cough, polio, measles, mumps, rubella and influenza B (the main cause of meningitis in childhood). However, since in less developed countries, infant mortality is mainly determined by infectious diseases, scientists are seeking to develop new vaccines that, if administered once. They could protect a child from several pathogens at once. Immunoglobulins that can quickly protect the body from snake bites, tetanus, botulism and diphtheria have already been examined.
Passive immunization – the introduction of antibodies to any antigens. You can only create a temporary immunity of 1-6 weeks with the help of passive immunization. Although passive immunization causes a short-term increase in resistance to the pathogen, its effect is immediately apparent. Repeated passive immunization does not enhance immunity and is often accompanied by complications. It is usually carried out after contact with the pathogen and when it is impossible to actively conduct immunization.
Passive immunization is used in order to create temporary immunity after contact with the infectious agent in cases when active immunization is not performed in advance for one reason or another (for example, against cytomegalovirus, rabies).
This type of immunization is also used to treat diseases caused by bacterial toxins (in particular, diphtheria), poisonous snake bites, spider bites and for specific (anti-Rh0 (D) -immunoglobulin) and non-specific (anti-lymphocytic immunoglobulin) immunosuppression.
Three types of drugs are used for passive immunization:
The immune serum is a preparation made from the blood of animals and humans containing antibodies against infectious agents or their metabolic products. It is used for serodiagnosis, seroprophylaxis and serotherapy.
The introduction of human serum from animal blood into humans can be accompanied by complications (serum sickness, anaphylactic shock). The concentrated immune serum is gamma globulins (more correctly – immunoglobulins, since they contain various globulin fractions) from human blood – practically do not cause these complications and are more slowly eliminated from the body.
Depending on the purpose, it is distinguished therapeutic and prophylactic and diagnostic immune serum. The treatment-and-prophylactic immune serum is divided into:
The diagnostic immune serum is prepared using different antigens depending on the nature of the reaction for which they are used. They are used to identify pathogens of infectious diseases, as well as in experimental studies, etc.