MECHANISMS OF IMMUNITY FORMATION.
Main function immune system- preserve what is “our own” and eliminate what is foreign. The carriers of “foreign” that the immune system encounters on a daily basis are primarily microorganisms. In addition to them, it is capable of eliminating malignant neoplasms and rejecting foreign tissue transplants. To achieve this, the immune system has a complex set of constantly interacting nonspecific and specific mechanisms. Nonspecific mechanisms are innate, while specific ones are acquired in the process of “immunological learning.”
Specific and nonspecific immunity.
Nonspecific (innate) immunitycauses the same type of reaction to any foreign antigens. The main cellular component of the nonspecific immune system are phagocytes, the main function of which is to capture and digest agents penetrating from outside. For such a reaction to occur, the foreign agent must have a surface, i.e. to be a particle (for example, a splinter).
If the substance is molecularly dispersed (for example: protein, polysaccharide, virus), and is not toxic and does not have physiological activity, it cannot be neutralized and eliminated by the body according to the scheme described above. In this case, the reaction is provided by specific immunity. It is acquired as a result of contact of the body with an antigen; has adaptive significance and is characterized by the formation of immunological memory. Its cellular carriers are lymphocytes, and its soluble carriers are immunoglobulins (antibodies).
Primary and secondary immune response.
Specific antibodies are produced by special cells - lymphocytes. Moreover, for each type of antibody there is its own type of lymphocyte (clone).
The first interaction of an antigen (bacterium or virus) with a lymphocyte causes a reaction called the primary immune response, during which the lymphocytes begin to develop (proliferate) in the form of clones, then undergoing differentiation: some of them become memory cells, others turn into mature cells that produce antibodies . The main features of the primary immune response are the existence of a latent period before the appearance of antibodies, then the production of them only in small quantities.
A secondary immune response develops upon subsequent exposure to the same antigen. Main Feature- rapid proliferation of lymphocytes with their differentiation into mature cells and rapid production of a large number of antibodies, which are released into the blood and tissue fluid, where they can meet the antigen and effectively fight the disease.
Natural and artificial immunity.
Factors of natural immunity include immune and non-immune mechanisms. The first include humoral (complement system, lysozyme and other proteins). The second includes barriers (skin, mucous membranes), the secretion of sweat, sebaceous, salivary glands(contains a variety of bactericidal substances), gastric glands ( hydrochloric acid and proteolytic enzymes), normal microflora (antagonists of pathogenic microorganisms).
Artificial immunity is produced when a vaccine or immunoglobulin is introduced into the body.
Active and passive immunity
There are two types of immunity: active and passive.
Active immunization stimulates a person's own immunity, causing the production of its own antibodies. It is produced in humans in response to a pathogen. Specialized cells (lymphocytes) are formed that produce antibodies to a specific pathogen. After an infection, “memory cells” remain in the body, and in the event of subsequent encounters with the pathogen, they begin to produce antibodies again (more quickly).
Active immunity can be natural or artificial. Natural is acquired as a result past illness. Artificial is produced when vaccines are administered.
Passive immunity: ready-made antibodies (gamma globulin) are introduced into the body. Injected antibodies in the event of a collision with a pathogen\"are consumed\" (they bind to the pathogen in the \"antigen-antibody\") complex; if there is no meeting with the pathogen, they have a certain half-life, after which they disintegrate. Passive immunization is indicated in cases where it is necessary to quickly create immunity for a short time (for example, after contact with a patient).
When a baby is born, he usually has immunity (immunity) to certain infections. This is thanks to disease-fighting antibodies that are passed through the placenta from mother to unborn baby. Antibodies are transmitted against the pathogens of those diseases with which the mother has been ill or against which she has been immunized. Subsequently, the breastfed baby constantly receives an additional portion of antibodies from the mother's milk. This is natural passive immunity. It is also temporary, fading away by the end of the first year of life.
Sterile and non-sterile immunity.
After illness, in some cases, immunity remains for life. For example, measles, chicken pox. This is sterile immunity. And in some cases, immunity lasts only as long as there is a pathogen in the body (tuberculosis, syphilis) - non-sterile immunity.
Immunoprophylaxis.
Immunoprophylaxis is a method of individual or mass protection of the population from infectious diseases by creating or strengthening artificial immunity.
Immunoprophylaxis is:
specific - against a specific pathogen
active - creating immunity by administering vaccines;
passive - creating immunity by administering serum drugs and gamma globulin;
nonspecific - activation of the immune system in general.
What is vaccination?
Vaccination is the most effective and cost-effective means of protection against infectious diseases known to modern medicine.
The basic principle of vaccination is that the patient is given a weakened or killed disease agent (or an artificially synthesized protein that is identical to the protein of the agent) in order to stimulate the production of antibodies to fight the disease-causing agent.
Among the microorganisms that are successfully combated by vaccinations may be viruses (for example, the causative agents of measles, rubella, mumps, polio, hepatitis B, rotavirus infection) or bacteria (the causative agents of tuberculosis, diphtheria, whooping cough, tetanus, Haemophilus influenzae).
\"Herd\" immunity.
How more people have immunity to a particular disease, the less likely the rest (non-immunized) are to get sick, the less likely an epidemic will occur. For example, if only one child is not vaccinated, and all the others have received the vaccine, then the unvaccinated child is well protected from the disease (he has no one to get infected from).
Vaccination and revaccination.
Vaccination can be either single (measles, mumps, tuberculosis) or multiple (poliomyelitis, DTP). The multiplicity tells you how many times you need to receive the vaccine to develop immunity. Revaccination is an event aimed at maintaining the immunity developed by previous vaccinations. Usually carried out several years after vaccination.
\"Tour\" vaccination
The catch-up vaccination plan includes a one-time initial vaccination carried out to quickly interrupt the chain of transmission of infection. Such preventive campaigns are usually carried out in a short time according to the following principle. All children, regardless of previous vaccinations or previous illness, are vaccinated within a period of 1 week to 1 month. Such an event is coordinated by the relevant ministry and carried out by local health authorities. At the same time, the capabilities of the media are used to attract the attention of the interested part of the population.
The epidemiological essence of tour vaccination is to additionally vaccinate population groups not covered by vaccination. Routine immunization is usually carried out in developing countries during infection eradication activities, where the coverage of children with vaccinations is low and the majority of vaccinated people do not have documented proof of vaccination. In such situations, the principle of vaccinating everyone "regardless of...\" justifies itself.
Effectiveness of vaccination
Post-vaccination immunity is immunity that develops after administration of a vaccine.
Vaccination is not always effective. Vaccines lose their quality if stored improperly. But even if the storage conditions are met, there is always a possibility that the immune system will not be stimulated.
The development of post-vaccination immunity is influenced by the following factors:
1.depending on the vaccine itself
Purity of the drug;
Antigen lifetime;
Dose;
Presence of protective antigens;
Frequency of administration.
2.depending on the body
State of individual immune reactivity;
Age;
The presence of immunodeficiency;
The condition of the body as a whole;
Genetic predisposition.
3.depending on the external environment
Nutrition;
Working and living conditions;
Climate;
Physicochemical environmental factors.
Types of vaccines.
All vaccines are divided into live and inactivated.
Inactivated vaccines, in turn, are divided into:
Corpuscular - are bacteria or viruses inactivated by chemical (formalin, alcohol, phenol) or physical (heat, ultraviolet irradiation) effects. Examples of corpuscular vaccines are: pertussis (as a component of DPT and Tetracoc), rabies, leptospirosis, whole virion influenza, vaccines against encephalitis, against hepatitis A (Avaxim), inactivated polio vaccine (Imovax Polio, or as a component of the Tetracoc vaccine).
Chemical - are created from antigenic components extracted from microbial cells. Those antigens are isolated that determine the immunogenic characteristics of the microorganism. These vaccines include: polysaccharide vaccines (Meningo A+S, Act-HIB, Pneumo 23, Typhim Vi), acellular pertussis vaccines.
Recombinant - to produce these vaccines, recombinant technology is used, integrating the genetic material of the microorganism into the yeast cells that produce the antigen. After cultivating the yeast, the desired antigen is isolated from it, purified, and a vaccine is prepared. An example of such vaccines is the hepatitis B vaccine (Euvax B). Inactivated vaccines They are produced both in dry (lyophilized) and liquid form.
Alive.
Live vaccines are made from weakened strains of microorganisms with persistently avirulent (harmless) properties. The vaccine strain, after administration, multiplies in the body of the vaccinated person and causes vaccine infectious process. In the majority of vaccinated people, the vaccine infection occurs without pronounced clinical symptoms and leads, as a rule, to the formation of stable immunity. Examples of live vaccines include vaccines for the prevention of rubella (Rudivax), measles (Ruvax), polio (Polio Sabin Vero), tuberculosis, mumps (Imovax Oreion). Live vaccines are produced in lyophilized (powdered) form (except polio).
Anatoxins.
These drugs are bacterial toxins that are rendered harmless by exposure to formaldehyde. elevated temperature followed by purification and concentration. Toxoids are sorbed on various mineral adsorbents, for example, aluminum hydroxide. Adsorption significantly increases the immunogenic activity of toxoids. This is due both to the creation of a “depot” of the drug at the injection site and to the adjuvant effect of the sorbent, which causes local inflammation, increased plasmacytic reaction in regional lymph nodes. Toxoids ensure the development of persistent immunological memory, this explains the possibility of using toxoids for emergency active prevention of diphtheria and tetanus.
Compound
In addition to the main active principle, vaccines may also contain other components - a sorbent, preservative, filler, stabilizer and non-specific impurities. The latter may include proteins of the substrate for the cultivation of viral vaccines, a trace amount of antibiotic and animal serum protein, used in some cases in the cultivation of cell cultures. Preservatives are included in vaccines produced throughout the world. Their purpose is to ensure the sterility of drugs in cases where conditions for bacterial contamination arise (the appearance of microcracks during transportation, storage of opened primary multi-dose packaging). An indication of the need for preservatives is contained in WHO recommendations. As for substances used as stabilizers and fillers, those used in the production of vaccines are those that are approved for introduction into the human body.
Disposal of unused vaccines
Ampules and other containers with unused remains of inactivated bacterial and viral vaccines, as well as live measles, mumps and rubella vaccines, toxoids, human immunoglobulins, heterologous sera, allergens, bacteriophages, eubiotics, as well as disposable instruments that were used for their administration are not subject to any special processing. Containers containing unused remains of other live bacterial and viral vaccines, as well as the equipment used for their administration, must be boiled for 60 minutes ( anthrax vaccine 2 hours), or treatment with a 3-5% solution of chloramine for 1 hour, or 6% solution of hydrogen peroxide (shelf life no more than 7 days) for 1 hour, or autoclaved. All unused batches of drugs that have expired, as well as those that cannot be used for other reasons, should be sent for destruction to the district (city) sanitary inspection center.
Question No. 1
Protective role immunity
Immunity (lat. immunitas- liberation, getting rid of something) - immunity, resistance of the body to infections and invasions of foreign organisms (including pathogens), as well as the effects of foreign substances with antigenic properties. Immune reactions also occur against the body’s own cells that are antigenically altered.
Provides homeostasis of the body at the cellular and molecular level of organization. Implemented by the immune system.
The biological meaning of immunity is to ensure the genetic integrity of the organism throughout its individual life. The development of the immune system made it possible for complexly organized multicellular organisms to exist.
The protective role of immunity extends not only to viruses, protozoa, fungi, helminths, but also to foreign tissue and organ transplants. It also applies to autoimmune processes that occur in the body. For example, in the mechanism of occurrence diabetes mellitus In humans, autoimmune processes against proteins contained in the cells of the islets of Langerhans of the pancreatic gland are important.
Infectious immunity
Infectious or as it is otherwise called non-sterile immunity is immunity human body to re-infection, due to the fact that this pathogen is already in the body. It exists for syphilis, malaria, tuberculosis and other similar diseases.
Activation of phagocytosis, as well as nonspecific defense factors, play a special role in its development.
It begins to develop when pathogens multiply in the body.
The form of immunity stability depends on the presence of the infection itself.
Infectious immunity has the main mechanisms: humoral (production of effector molecules - antibodies) and cellular (formation of effector cells).
It is classified into several types: antimicrobial, which is also called antibacterial, antiviral and antitoxic.
With antiviral immunity (influenza and other viral diseases) viral particles are destroyed.
With antimicrobial (for dysentery), bacterial pathogens are neutralized, and in the case of antitoxic (for tetanus, botulism), the toxin that is produced by microbes in the body is destroyed.
Infectious immunity is divided into two types: innate and acquired.
Innate immunity
Innate immunity is the body’s ability to neutralize foreign and potentially dangerous biomaterial (microorganisms, transplant, toxins, tumor cells, cells infected with a virus), which exists initially, before the first entry of this biomaterial into the body.
The innate immune system is much more evolutionarily ancient than the acquired immune system and is present in all species of plants and animals, but has been studied in detail only in vertebrates. Compared to the acquired immune system, the innate immune system is activated more quickly when a pathogen first appears, but recognizes the pathogen with less accuracy. It reacts not to specific specific antigens, but to certain classes of antigens characteristic of pathogenic organisms(polysaccharides cell wall bacteria, double-stranded RNA of some viruses, etc.).
Innate immunity has cellular (phagocytes, granulocytes) and humoral (lysozyme, interferons, complement system, inflammatory mediators) components. A local nonspecific immune reaction is otherwise called inflammation.
Acquired immunity: active and passive
Acquired immunity is the body’s ability to neutralize foreign and potentially dangerous microorganisms (or toxin molecules) that have previously entered the body. There are active and passive acquired immunity.
Active can occur after an infectious disease or a vaccine has been introduced into the body. It forms in 1-2 weeks and persists for years or tens of years. Passively acquired occurs when ready-made antibodies are transferred from mother to fetus through the placenta or from breast milk, providing newborns with immunity to some for several months infectious diseases. Such immunity can also be created artificially by introducing into the body immune serums containing antibodies against the corresponding microbes or toxins (traditionally used for bites of poisonous snakes).
Like innate immunity, acquired immunity is divided into cellular (T lymphocytes) and humoral (antibodies produced by B lymphocytes; complement is a component of both innate and acquired immunity).
Vaccines and serums
Vaccines and serums are used as active or passive immunostimulants. Such drugs are especially effective if they are used not only for treatment, but also for the prevention of infectious diseases.
Vaccines are produced directly from microorganisms causing infections, or from their antigens. A vaccine helps the body produce antibodies on its own to fight viruses or infections.
Depending on the origin, vaccines are divided into:
· corpuscular vaccines (such preparations are made from killed microbes that cause the disease),
attenuated vaccines (made from weakened microorganisms),
· chemical vaccines, in which antigens are created in a laboratory by chemical means (in particular, vaccines against hepatitis B).
Corpuscular or inactive vaccines are used against tick-borne encephalitis, polio, influenza, cholera, etc. Such drugs do not immediately develop immunity; several vaccinations are necessary. Attenuated vaccines are the most effective immune preparations; they produce lasting immunity the first time. Such vaccines are used against plague, typhoid, measles, rubella, as well as influenza and polio.
Serums, despite their apparent similarity to vaccines, are blood plasma without fibrinogen. Serum is obtained by natural plasma coagulation or with the help of calcium ions, which precipitate fibrinogen. When the serum is administered, the immune system is also formed. Serum is usually made from animal blood, but in some cases the most effective serum is based on human blood - immunoglobulins (or gamma globulins). They are used for the prevention and treatment of whooping cough, measles, infectious hepatitis, etc. Gamma globulins do not cause allergic reactions. Serums contain ready-made antibodies, which are used, if the body cannot produce them on its own due to severe immunodeficiency, for the treatment and prevention of viral or bacterial infections(but not in acute form). Serums can be used after organ transplantation to prevent their possible rejection by the body. Serums are also used to create immunity to infection in a person if he has to come into contact with already sick people or carriers of certain viruses.
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Worst Best
There are mechanisms of “non-immune”, natural non-specific resistance of the body. These include protecting the body from external agents by external integuments (skin, mucous membranes), mechanical (desquamation of the epithelium, movement of cilia and secretions, sneezing, coughing), physical mechanisms(fever), chemicals(bactericidal effect of hydrochloric, lactic, fatty acids, a number of enzymes, especially lysozyme - muramidase).
Nonspecific factors of true immunity should be distinguished from nonspecific, “nonimmune” resistance. They include cells and humoral factors. These are phagocytes (monocytes, macrophages, polymorphonuclear leukocytes), which exhibit their activity in all tissues, cavities, and can reach the surface of the mucous membranes and perform a protective function there. Humoral factors of nonspecific immunity are also diverse: the complement system, nonspecific globulins, C-reactive protein, enzyme lysozyme, interferons, cytokines, etc.
C-reactive protein. Proteins are involved in nonspecific immunity against microbes acute phase inflammation: C-reactive protein (CRP), serum amyloid, alpha2-macroglobulin, fibrinogen, etc. The effect of CRP on bacteria resembles the effect of antibodies. CRP consists of five polypeptide chains forming a closed pentamer. With the participation of calcium ions, it nonspecifically binds to microorganisms if their membrane contains phosphorylcholine. The resulting complex activates complement (see below) along the classical pathway, similar to the antigen-antibody complex. As a result, microbes are either lysed or opsonized due to the appearance of active (C3b, etc.) complement components on their surface, which promotes phagocytosis, because phagocytes have receptors for these complement components.
Interferons. This is a heterogeneous group of protein molecules. There are 4 known types of interferons - alpha interferon, omega interferon (leukocyte), beta interferon (fibroblast), gamma interferon - immune (T-cell). Alpha interferon and omega interferon have antiviral and antiproliferative, antitumor effects. Interferon beta enhances the expression of HLA antigens on cells, activates natural killer cells (NK) and phagocytes. Interferon gamma enhances the antiviral and antiproliferative effects of the previous ones. In addition, it is an important immunoregulator. It is mainly produced by T helper cells. Gamma interferon enhances the synthesis of HLA antigens by cells, which leads to acceleration of the processes of recognition and processing of antigens, activates natural killer cells, T - and B-lymphocytes, antibody genesis, adhesion of leukocytes and monocytes, phagocytosis.
Based on the mechanism of development, the following types of immunity are distinguished.
Species immunity(constitutional, hereditary) - this is a special version of the body’s nonspecific resistance, genetically determined by the metabolic characteristics of a given species. It is mainly due to the lack necessary conditions for pathogen propagation. For example, animals do not suffer from some human diseases (syphilis, gonorrhea, dysentery), and, conversely, people are immune to the causative agent of canine distemper. Strictly speaking, this type of resistance is not true immunity, since it is not carried out by the immune system. However, there are variants of species immunity due to natural, pre-existing antibodies. Such antibodies are available in small quantities against many bacteria and viruses.
Acquired immunity occurs during life. It can be natural and artificial, each of which can be active or passive.
Natural active immunity appears as a result of contact with a pathogen (after an illness or after hidden contact without showing symptoms of the disease).
Natural passive immunity occurs as a result of transmission from mother to fetus through the placenta (transplacental) or with milk of ready-made protective factors - lymphocytes, antibodies, cytokinesis, etc.
Artificial active immunity is induced after the introduction into the body of vaccines containing microorganisms or their substances - antigens.
Artificial passive immunity is created after the introduction of ready-made antibodies into the body or immune cells. Such antibodies are found in the blood serum of immunized donors or animals.
Based on the reacting systems, local and general immunity are distinguished. Local immunity involves nonspecific protective factors, as well as secretory immunoglobulins, which are found on the mucous membranes of the intestines, bronchi, nose, etc.
There are also anti-infectious and non-infectious immunity.
Anti-infective immunity- a set of reactions of the immune system aimed at removing the infectious agent - the causative agent of the disease. According to R.V. Petrov, this is a method of protection from living bodies and substances carrying foreign genetic information.
Depending on the type of infectious agent, the following types of anti-infective immunity are distinguished:
1. Antibacterial, which can be sterile and non-sterile. When sterile, microorganisms are removed from the body, and immunity is preserved. If it is non-sterile, the presence of a small number of microorganisms in the body is necessary to maintain immunity.
2. Antitoxic - against waste products of microbial toxins.
3. Antiviral - against viruses or their antigens.
4. Antifungal - against pathogenic fungi.
Immunity is always specific, directed against specific pathogen disease, virus, bacteria. Therefore, there is immunity to one pathogen, for example, the measles virus, but not to another (the influenza virus). This specificity and specificity is determined by antibodies and receptors immune T cells against the corresponding antigens.
Non-infectious immunity- a set of reactions of the immune system aimed at non-infectious biologically active agents-antigens. Depending on the nature of these antigens, it is divided into the following types:
1. Autoimmunity - autoimmune reactions of the immune system to its own antigens (proteins, lipoproteins, glycoproteins). It is caused by a violation of the recognition of “self” molecules, when they are perceived by the immune system as “foreign” and are destroyed.
2. Transplantation immunity occurs when organs and tissues are transplanted from a donor to a recipient, in cases of blood transfusion and immunization with leukocytes. These reactions are associated with the presence of individual sets of molecules on the surface of leukocytes - human leukocyte antigens - HLA. The set of these molecules is identical only in identical twins.
3. Antitumor immunity is the reaction of the immune system to antigens of tumor cells.
4. Reproductive immunity in the mother-fetus system. These are the mother’s reactions to fetal antigens, since the fetus differs in them due to genes received from the father.
Every year medicine amazes with more and more new discoveries among medicinal drugs and technology. But there is medications time-tested , for which there is no point in looking for analogues. This especially applies to various vaccines for many occasions.
They have been actively used for quite a long time vaccines for babies , they are intended to develop immunity against diseases and infections that are difficult for a child’s fragile body to cope with.
Such artificial passive immunity is developed after administration of the above-mentioned vaccine, serums.
Artificial immunity and its subtypes
Everyone knows about the existence natural immunity. It is individual for each person, and relative to each disease.
Artificial immunity cannot be acquired without medical or medication assistance.
Artificial immunity can be active or passive . Passive is much more popular in medicine. Its essence lies in the fact that antibodies ready to fight for a certain type of disease are introduced into the body.
Each serum can affect a person or child differently. It all depends on how well your body accepts it. Maybe, natural immunity will be stronger and the vaccine will not play a special role.
At worst– the effectiveness of the serum may be very low and the person is still at risk of contracting the infection. In addition, the effect of the serum is quite transient and can only protect for a certain period of time.
Vaccine composition
Artificial passive immunity is developed after the administration of serum with a specific composition
. It is not used for other purposes.
Vaccination has its own specific periods conduction, as well as the composition of the serum. In general, this results in a similar situation:
An epidemic of the disease has been noticed in medicine or everything goes towards this. Moreover, this disease can be transmitted in a rather complex form, and many medications provide only a temporary effect, if any.
A successfully cured person is found, ready to donate his blood.
Blood plasma is released, from which antibodies against common diseases are released.
The resulting serum is administered to patients for preventive methods., as well as for a speedy recovery if viruses have already entered the human body.
Action occurs almost instantly, but not for a long period.
The most common are serums against tetanus and rabies.
Vaccines can be repeated after a certain period of time, but only in cases where there is a need. Therefore, if there are no multiple cases of victims of the same virus in your area, you should not transfer a vaccine that can save someone’s life. 
Artificial immunity in infants
Artificial passive immunity is especially important for newborns and pre-one-year-old children, and it is still produced after the introduction of a special vaccine.
In such situations, the frequency of cases of the disease is not important, since the goal is somewhat different - help the child grow to the age when he begins to develop his natural immunity .
After birth and in the first months of life, the baby’s body only begins to adapt to environment, therefore most susceptible to various viruses and bacteria. Moreover, even a simple cold for such a young organism will serious illness.
Precisely for this purpose to protect the baby, he is given a general immune vaccine with a relatively long period of action.
Thus, with the help of vaccination you can insure yourself against many diseases.
Specific immunity divided into congenital (species) and acquired .
Innate immunity inherent in a person from birth, inherited from parents. Immune substances pass through the placenta from mother to fetus. A special case of innate immunity can be considered the immunity received by a newborn through mother's milk.
Acquired immunity occurs (acquired) during life and is divided into natural and artificial.
Natural acquired immunity occurs after suffering an infectious disease: after recovery, antibodies to the causative agent of this disease remain in the blood. Often people, having had illnesses in childhood, for example, measles or chicken pox, in the future they either do not get sick with this disease at all, or get sick again in a mild, erased form.
Artificial immunity is developed through special medical measures, and it can be active or passive.
Active artificial immunity occurs as a result of preventive vaccinations, when a vaccine is introduced into the body - or weakened pathogens of a particular disease ("live" vaccine), or toxins - waste products of pathogenic microorganisms ("dead" vaccine). In response to the introduction of the vaccine, a person seems to fall ill with the disease, but in a very mild, almost imperceptible form. His body actively produces protective antibodies. And although active artificial immunity does not appear immediately after the vaccine is administered (antibodies take some time to develop), it is quite strong and lasts for many years, sometimes throughout life. The closer a vaccine immunopreparation is to a natural infectious agent, the higher its immunogenic properties and the stronger the resulting post-vaccination immunity. Vaccination with a live vaccine, as a rule, provides complete immunity to the corresponding infection for 5-6 years, vaccination with an inactivated vaccine creates immunity for the next 2-3 years, and the introduction of a chemical vaccine and toxoid provides protection of the body for 1-1.5 years. At the same time, the more the vaccine is purified, the less likely it is that unwanted, side reactions will occur after its introduction into the human body. Examples of active immunity include vaccinations against polio, diphtheria, and whooping cough.
Passive artificial immunity occurs as a result of the introduction into the body of serum - defibrinated blood plasma that already contains antibodies to a particular disease. Serum is prepared either from the blood of people who have recovered from the disease, or, more often, from the blood of animals that are specially inoculated with the disease and in whose blood specific antibodies are formed. Passive artificial immunity occurs almost immediately after the administration of serum, but since the injected antibodies are essentially foreign, i.e. have antigenic properties, over time the body suppresses their activity. Therefore, passive immunity is relatively unstable. Immune serum and immunoglobulin, when introduced into the body, provide artificial passive immunity that retains a protective effect for a short time (4-6 weeks). The most typical example of passive immunity is anti-tetanus and anti-rabies serum.
The bulk of vaccinations are carried out in pre-school and preschool age. At school age, revaccination is carried out aimed at maintaining the proper level of immunity. An immunization schedule is a rule-prescribed sequence of vaccinations with a specific vaccine, which specifies the age of the child to be immunized, prescribes the number of required vaccinations against a given infection, and recommends certain time intervals between vaccinations. There is a special, legally approved vaccination calendar for children and adolescents (general schedule of immunization regimens). The administration of serums is used in cases where the likelihood of a particular disease is high, as well as in the early stages of the disease, to help the body cope with the disease. For example, vaccinations against influenza when there is a threat of an epidemic, vaccinations against tick-borne encephalitis before leaving for field practice, the bite of a rabid animal, etc.
