How different types of vaccines are made. What are vaccines and what are they? What is a vaccine? Types and types of vaccines

Vaccines - immunobiological preparations intended for active immunoprophylaxis, that is, to create active specific immunity of the organism to a specific pathogen. Vaccination recognized by WHO ideal method prevention of human infectious diseases. High efficiency, simplicity, the possibility of wide coverage of vaccinated persons with the aim of mass prevention of the disease have brought active immunoprophylaxis in most countries of the world into the category of state priorities. The complex of measures for vaccination includes the selection of persons to be vaccinated, the choice of a vaccine preparation and the determination of the scheme of its use, as well as (if necessary) control of the effectiveness, relief of possible pathological reactions and complications. The following are used as Ag in vaccine preparations:

Whole microbial bodies (live or killed);
individual Ags of microorganisms (most often protective Ags);
toxins of microorganisms;
artificially created AG of microorganisms;
Ag obtained by genetic engineering.

Most vaccines divided into living, inactivated (killed, inanimate), molecular (toxoid), genetically engineered and chemical; according to the presence of a complete or incomplete set of Ar - into corpuscular and component, and according to the ability to develop immunity to one or several pathogens - into mono- and associated.

Live vaccines

Live vaccines - preparations from attenuated (weakened) or genetically modified pathogenic microorganisms, as well as closely related microbes that can induce immunity to a pathogenic species (in the latter case, we are talking about the so-called divergent vaccines). Since all live vaccines contain microbial bodies, then they are referred to the group of corpuscular vaccine preparations.

Immunization with live vaccine leads to the development of the vaccination process, which occurs in the majority of vaccinated without visible clinical manifestations... The main advantage of live vaccines is a fully preserved set of Ag of the pathogen, which ensures the development of long-term immunity even after a single immunization. Live vaccines also have a number of disadvantages. The most characteristic is the risk of developing an overt infection as a result of a decrease in the attenuation of the vaccine strain. Similar phenomena are more typical for antiviral vaccines (for example, a live polio vaccine in rare cases can cause poliomyelitis up to the development of spinal cord injury and paralysis).

Attenuated (attenuated) vaccines

Weakened ( attenuated) vaccines made from microorganisms with reduced pathogenicity, but pronounced immunogenicity. The introduction of a vaccine strain into the body mimics the infectious process: the microorganism multiplies, causing the development of immune reactions. The best known vaccines are for the prevention of anthrax, brucellosis, Q fever, and typhoid fever. but most of live vaccines - antiviral. The most famous are the vaccine against the causative agent of yellow fever, Seibin's polio-myelitis vaccine, influenza, measles, rubella, mumps and adeno vaccines. viral infections.

Divergent vaccines

As vaccine strains are used by microorganisms closely related to the causative agents of infectious diseases. Ag of such microorganisms induce an immune response cross-directed to the Ag of the pathogen. The most well-known and long-term use of the vaccine against smallpox (from vaccinia virus) and BCG for the prevention of tuberculosis (from mycobacterium bovine tuberculosis).

Over the centuries, mankind has experienced more than one epidemic that claimed the lives of many millions of people. Thanks to modern medicine, it has been possible to develop drugs to avoid many deadly diseases. These drugs are called "vaccines" and are classified into several types, which we will describe in this article.

What is a vaccine and how does it work?

The vaccine is medical drugcontaining killed or weakened pathogens various diseases or synthesized proteins of pathogenic microorganisms. They are injected into the human body to create immunity to a certain disease.

Administration of vaccines to human body called vaccination, or vaccination. The vaccine, entering the body, induces the human immune system to produce special substances to destroy the pathogen, thereby forming in him a selective memory for the disease. Subsequently, if a person becomes infected with this disease, his immune system will quickly respond to the pathogen and the person will not get sick at all or suffer easy form disease.

Vaccination methods

Immunobiological drugs can be administered different ways according to the instructions for vaccines, depending on the type of drug. There are the following methods of vaccination.

• The introduction of the vaccine intramuscularly. The place of vaccination in children under one year old is the upper surface of the middle of the thigh, and for children from 2 years of age and adults, it is preferable to inject the drug into the deltoid muscle, which is located in the upper part of the shoulder. The method is applicable when an inactivated vaccine is needed: DPT, ADS, against viral hepatitis B and influenza vaccine.

Parental reviews suggest that infants tolerate vaccination better in upper part thighs rather than in the buttock. Physicians adhere to the same opinion, explaining this by the fact that in the gluteal region there may be an abnormal placement of nerves, which occurs in 5% of children under one year old. In addition, children of this age have a significant fat layer in the gluteal region, which increases the likelihood of the vaccine entering the subcutaneous layer, which reduces the effectiveness of the drug.

• Subcutaneous injections are injected with a thin needle under the skin in the deltoid or forearm. An example is BCG, smallpox vaccination.

• The intranasal method is applicable for vaccines in the form of an ointment, cream or spray (measles, rubella vaccination).
• The oral route is when a droplet vaccine is placed in the patient's mouth (polio).

Types of vaccines

Today, in the hands of medical workers in the fight against dozens of infectious diseases, there are more than a hundred vaccines, thanks to which it was possible to avoid whole epidemics and significantly improve the quality of medicine. It is conventionally accepted to distinguish 4 types of immunobiological drugs:

1. Live vaccine (against poliomyelitis, rubella, measles, mumps, flu, tuberculosis, plague, anthrax).
2. Inactivated vaccine (against whooping cough, encephalitis, cholera, meningococcal infection, rabies, typhoid fever, hepatitis A).
3. Toxoids (tetanus and diphtheria vaccines).
4. Molecular or biosynthetic vaccines (for hepatitis B).

Types of vaccines

Vaccines can also be grouped according to their composition and method of obtaining them:

1. Corpuscular, that is, consisting of whole microorganisms of the pathogen.
2. Component or acellular consists of parts of the pathogen, the so-called antigen.
3. Recombinant: This group of vaccines contains antigens from a pathogenic microorganism that have been genetically engineered into the cells of another microorganism. The representative of this group is the influenza vaccine. Another striking example is the vaccine against viral hepatitis B, which is obtained by introducing an antigen (HBsAg) into the cells of yeast fungi.

Another criterion by which a vaccine is classified is the number of diseases or pathogens it prevents:

1. Monovalent vaccines are used to prevent only one disease (for example, bCG vaccine against tuberculosis).
2. Polyvalent or associated - for vaccination against several diseases (for example, DPT against diphtheria, tetanus and whooping cough).

Live vaccine

Live vaccine - This is an irreplaceable drug for the prevention of many infectious diseases, which is found only in corpuscular form. Characteristic feature This type of vaccine is considered that its main component is weakened strains of the infectious agent that can multiply, but are genetically devoid of virulence (the ability to infect the body). They contribute to the body's production of antibodies and immune memory.

The advantage of live vaccines is that the pathogens that are still live, but weakened, induce the human body to develop long-term immunity (immunity) to this pathogenic agent, even with a single vaccination. There are several ways to administer the vaccine: intramuscularly, under the skin, and nasal drops.

The disadvantage is that a gene mutation of pathogenic agents is possible, which will lead to the disease of the vaccinated. In this regard, it is contraindicated for patients with particularly weakened immunity, namely for people with immunodeficiency and cancer patients. Requires special conditions for the transportation and storage of the drug in order to ensure the safety of living microorganisms in it.

Inactivated vaccines

The use of vaccines with inactivated (dead) pathogenic agents is widespread for the prevention of viral diseases. The principle of action is based on the introduction into the human body of artificially cultivated and devoid of viability viral pathogens.

In terms of composition, “killed” vaccines can be either whole-microbial (whole-viral) or subunit (component) and genetically engineered (recombinant).

An important advantage of "killed" vaccines is their absolute safety, that is, the absence of the likelihood of infection of the vaccinated and the development of infection.

The disadvantage is a lower duration of immune memory compared to "live" vaccinations, inactivated vaccines also retain the likelihood of developing autoimmune and toxic complications, and to form a full-fledged immunization several vaccination procedures are required with maintaining the required interval between them.

Toxoid

Toxoids are vaccines created on the basis of disinfected toxins released during the life of some pathogens of infectious diseases. The peculiarity of this vaccination is that it provokes the formation of not microbial immunity, but antitoxic immunity. Thus, toxoid is successfully used for the prevention of those diseases in which clinical symptoms associated with a toxic effect (intoxication) resulting from the biological activity of a pathogenic agent.

Release form - transparent liquid with sediment in glass ampoules. Before use, you need to shake the contents to evenly distribute the toxoid.

The advantages of toxoids are indispensable for the prevention of those diseases against which live vaccines are powerless, moreover, they are more resistant to temperature fluctuations, do not require special conditions for storage.

Disadvantages of toxoids - they induce only antitoxic immunity, which does not exclude the possibility of the occurrence of localized diseases in the vaccinated person, as well as the carriage of pathogens of this disease by him.

Making live vaccines

The vaccine began to be mass produced at the beginning of the 20th century, when biologists learned to weaken viruses and pathogenic microorganisms. Live vaccine is about half of all prophylactic drugs used in world medicine.

The production of live vaccines is based on the principle of reseeding the pathogen into an organism that is immune or slightly susceptible to a given microorganism (virus), or the cultivation of the pathogen in unfavorable conditions for it with the effect of physical, chemical and biological factors on it, followed by selection of non-virulent strains. Most often, the substrate for the cultivation of avirulent strains is chicken embryos, primary cell (chicken or quail ebryonic fibroblasts) and transplanted cultures.

Getting “killed” vaccines

The production of inactivated vaccines differs from live ones in that they are obtained by killing, and not by attenuating, the pathogen. For this, only those pathogenic microorganisms and viruses that have the highest virulence are selected, they should be one population with clearly defined characteristics for it: shape, pigmentation, size, etc.

Inactivation of pathogen colonies is carried out in several ways:

• overheating, that is, exposure to the cultured microorganism elevated temperature (56-60 degrees) a certain time (from 12 minutes to 2 hours);
• exposure to formalin for 28-30 days with maintaining the temperature at 40 degrees, a solution of beta-propiolactone, alcohol, acetone, chloroform can also act as an inactivating chemical reagent.

Making toxoids

In order to obtain a toxoid, the toxogenic microorganisms are first cultivated in a nutrient medium, most often of a liquid consistency. This is done in order to accumulate as much exotoxin as possible in the culture. The next stage is the separation of the exotoxin from the producer cell and its neutralization using the same chemical reactions that are used for “killed” vaccines: exposure to chemicals and overheating.

To reduce reactivity and susceptibility, antigens are cleaned of ballast, concentrated and adsorbed with aluminum oxide. The process of adsorption of antigens plays an important role, since the injected injection with a high concentration of toxoids forms a depot of antigens, as a result, antigens enter and spread throughout the body slowly, thereby ensuring an effective immunization process.

Destruction of unused vaccine

Regardless of which vaccines were used for vaccination, containers with drug residues must be treated in one of the following ways:

• boiling used containers and instruments for an hour;
• disinfection in a solution of 3-5% chloramine for 60 minutes;
• treatment with 6% hydrogen peroxide also for 1 hour.

Expired drugs must be sent to the regional sanitary and epidemiological center for disposal.

Vaccines (the definition, the classification of which is considered in this article) are immunological agents used as active immunoprophylaxis (otherwise, for the formation of an active persistent immunity of the organism to this particular pathogen). According to the WHO conclusion, vaccination is the best method for the prevention of infectious pathologies. Due to the high efficiency, simplicity of the method, the possibility of a wide coverage of the vaccinated population for the mass prevention of pathologies, immunoprophylaxis in many countries is classified as a state priority.

Vaccination

Vaccinations are special preventive measures, aimed at protecting a child or an adult from certain pathologies completely or significantly reducing their appearance when they occur.

A similar effect is achieved through "training" immunity. With the introduction of the drug, the body (or rather its the immune system) fights against artificially introduced infection and "remembers" it. With re-infection, immunity is activated much faster and completely destroys foreign agents.

The list of ongoing vaccination activities includes:

• selection of persons to be vaccinated;
• choice of drug;
• formation of a vaccine administration scheme;
• efficiency control;
• therapy (if necessary) of probable complications and pathological reactions.

Vaccination methods

• Intradermal. An example is BCG. The introduction is made in the shoulder (its outer third). Similar method It is also used to prevent tularemia, plague, brucellosis, Siberian ulcers, and Q fever.
• Oral. It is used to prevent polio and rabies. Oral drugs for influenza, measles, typhoid fever, meningococcal infection are under development.
• Subcutaneous. With this method, the non-sorbed drug is injected into the subscapularis or shoulder (outer surface at the border of the middle and upper third of the shoulder) area. Advantages: low allergenicity, ease of administration, immunity stability (both local and general).
• Aerosol. It is used as an emergency immunization. Aerosol agents against brucellosis, influenza, tularemia, diphtheria, Siberian ulcers, whooping cough, plague, rubella, gas gangrene, tuberculosis, tetanus, typhoid fever, botulism, dysentery, and mumps B are highly effective.
• Intramuscular. It is produced in the muscles of the thigh (in the upper antero-outer part of the quadriceps femoral muscle). For example, DTP.

Modern classification of vaccines

There are several divisions of vaccine products.

1. Classification of funds according to generation:

• 1st generation (corpuscular vaccines). In turn, they are divided into attenuated (weakened live) and inactivated (killed) agents;
• 2nd generation: subunit (chemical) and neutralized exotoxins (toxoids);
• 3rd generation is represented by recombinant and recombinant rabies vaccines;
• 4th generation (not yet included in practice), represented by plasmid DNA, synthetic peptides, plant vaccines, vaccines that contain MHC products and anti-idiotypic drugs.

2. Classification of vaccines (microbiology also divides them into several classes) by origin. By origin, vaccines are divided into:

• live, which are made from live, but weakened microorganisms;
• killed, created on the basis of microorganisms inactivated by various methods;
• vaccines of chemical origin (based on highly purified antigens);
• vaccines that are created using biotechnological methods, in turn, are subdivided into:

Synthetic vaccines based on oligosaccharides and oligopeptides;

DNA vaccines;

Genetic engineering vaccines created on the basis of products resulting from the synthesis of recombinant systems.

3. In accordance with the composition of Ag preparations, there is the following classification of vaccines (that is, they may be present as Ag in vaccines):

• whole microbial cells (inactivated or live);
• individual components of microbial bodies (more often protective Ag);
• microbial toxins;
• synthetically created Ag of microbes;
• Ag that are obtained using genetic engineering techniques.

Depending on the ability to develop insensitivity to several or one agent:

• monovaccines;
• polyvaccines.

Classification of vaccines according to the set of Ag:

• component;
• corpuscular.

Live vaccines

For the manufacture of such vaccines, attenuated strains of infectious agents are used. Such vaccines have immunogenic properties, however, the onset of symptoms of the disease during immunization, as a rule, do not cause.

As a result of the penetration of a live vaccine into the body, a stable cellular, secretory, humoral immunity is formed.

Advantages and disadvantages

Benefits (classification, application are discussed in this article):

• a minimum dosage is required;
• the possibility of various methods of vaccination;
• rapid development of immunity;
• high efficiency;
• low price;
• immunogenicity is maximally natural;
• there are no preservatives in the composition;
• under the influence of such vaccines, all types of immunity are activated.

Negative sides:

• if the patient has a weakened immunity with the introduction of a live vaccine, the development of the disease is possible;
• vaccines of this type are extremely sensitive to temperature extremes, and therefore, when a "spoiled" live vaccine is introduced, negative reactions develop or the vaccine completely loses its properties;
• the impossibility of combining such vaccines with other vaccine preparations, due to the development of adverse reactions or loss of therapeutic efficacy.

Live vaccine classification

There are the following types of live vaccines:

• Attenuated (attenuated) vaccine preparations. They are produced from strains that have reduced pathogenicity, but pronounced immunogenicity. With the introduction of a vaccine strain, a semblance of an infectious process develops in the body: infectious agents multiply, thereby causing the formation of immune reactions. Among such vaccines, the most famous are drugs for the prevention of typhoid fever, Siberian ulcers, Q fever and brucellosis. But still the main part of live vaccines - antiviral drugs from adenovirus infections, yellow fever, Sabin (against poliomyelitis), rubella, measles, flu;
• Divergent vaccines. They are made on the basis of related pathogens of infectious pathologies of strains. Their antigens provoke the emergence of an immune response, cross-directed to the antigens of the pathogen. An example of such vaccines is the vaccine-prophylaxis against smallpox, which is made on the basis of the vaccinia virus and BCG, on the basis of mycobacteria that cause bovine tuberculosis.

Flu vaccines

Vaccines are used as the most effective prevention of influenza. They are biological agents that provide short-term resistance to influenza viruses.

The indications for such vaccination are:

• age 60 and older;
• chronic bronchopulmonary or cardiovascular pathologies;
• pregnancy (2-3 trimesters);
• outpatient and hospital staff;
• persons constantly staying in closed collectives (prisons, dormitories, nursing homes, and so on);
• patients who are inpatient or outpatient treatmentthat have hemoglobinopathies, immunosuppression, liver, kidney and metabolic disorders.

Varieties

The classification of influenza vaccines includes the following groups:

1. Live vaccines;
2. Inactivated vaccines:

• whole virion vaccines. Includes intact highly purified inactivated virions;
• split (split vaccines). For example: "Fluarix", "Begrivak", "Vaxigrip". Created on the basis of destroyed influenza virions (all proteins of the virus);

• subunit vaccines (Agrippal, Grippol, Influvac) contain two viral surface proteins, neuraminidase and hemagglutinin, which induce an immune response in influenza. Other proteins of the virion, as well as the chicken embryo, are absent, since they are eliminated during purification.

From WikiDOL

COMPOSITORS: Doctor of medical sciences, prof. M.A. Gorbunov, doctor of medical sciences, prof. N.F. Nikityuk, Ph.D. G.A. Elshina, Ph.D. V.N. Ikoev, Ph.D. N.I. Lonskaya, K. b. n. K.M. Mefed, M.V. Solovyova, Federal State Budgetary Institution "NTsESMP" of the Ministry of Health and Social Development of Russia, Center for Examination and Control of ILP

Vaccines are drugs obtained from live attenuated strains or killed cultures of microorganisms and their antigens, designed to create an active immune response in the body of vaccinated people and animals.

Among the various groups of biological medicinal products used for immunoprophylaxis and immunotherapy of infectious diseases, vaccines are the most effective remedy prevention of infectious diseases. The main active principle of each vaccine is an immunogen, which is similar in structure to the components of the pathogen responsible for the development of immunity.

Depending on the nature of the immunogen, vaccines are divided into:

• alive;

• killed (inactivated);

• split (split vaccines);

• subunit (chemical) vaccines;

• toxoid;

• recombinant;

• conjugated;

• virosomal;

• artificial adjuvant vaccines;

• combined (associated polyvaccines).

Live vaccines

Live vaccines contain weakened live microorganisms (bacteria, viruses, rickettsia), created on the basis of apathogenic pathogens, attenuated in artificial or natural conditions, by inactivation of genes or due to their mutations. Live vaccines create a stable and long-term immunity, which is close in intensity to post-infectious immunity, while a single injection of the drug is usually sufficient to develop immunity. The vaccine infectious process lasts several weeks, is not accompanied by clinical picture diseases and leads to the formation of specific immunity.

Killed (inactivated) vaccines

Killed vaccines are prepared from inactivated virulent strains of bacteria and viruses and contain a killed whole microorganism, or components of the cell wall and other parts of the pathogen that have a full set of necessary antigens. For inactivation of pathogens, physical (temperature, radiation, UV rays) or chemical (alcohol, acetone, formaldehyde) methods are used, which ensure minimal damage to the structure of antigens. These vaccines have a lower immunological efficacy than live vaccines, therefore, vaccination is carried out mainly in 2 or 3 doses and requires revaccination, which forms a sufficiently stable immunity, protecting the vaccinated against the disease or reducing its severity.

Split vaccines (split vaccines)

Vaccines contain destroyed inactivated virions, while retaining all the proteins of the virus (surface and internal). Due to the high purification from viral lipids and proteins of the chicken embryo, the substrate for cultivation, split vaccines have low reactogenicity. High degree specific safety and sufficient immunogenicity allow their use among children from 6 months of age and pregnant women.

Subunit (chemical) vaccines

Subunit vaccines consist of individual antigens of the microorganism, capable of providing a reliable immune response in the vaccinated. To obtain protective antigens, various chemical methods are mainly used, followed by purification of the resulting material from ballast substances. The use of adjuvants enhances the effectiveness of vaccines. subunit (chemical) vaccines have weak reactogenicity, can be administered in large doses and repeatedly, and also be used in various associations aimed simultaneously against a number of infections.

Toxoid

Toxoid are prepared from microbial exotoxins that have lost their toxicity as a result of neutralization with formaldehyde when heated, but retained their specific antigenic properties and the ability to cause the formation of antibodies (antitoxins). Purified from ballast substances and concentrated toxoid is sorbed on aluminum hydroxide. Toxoids form antitoxic immunity, which is weaker than post-infectious immunity.

Recombinant vaccines (vector)

Recombinant vaccines are obtained by cloning genes that provide the synthesis of the necessary antigens, by introducing these genes into the vector and into producer cells (viruses, bacteria, fungi, etc.), then the cells are cultured in vitro, the antigen is separated and purified. The new technology has opened up broad prospects for the creation of vaccines. Recombinant vaccines are safe, quite effective, highly effective technology is used to obtain them, they can be used to develop complex vaccines that create immunity against several infections simultaneously.

Conjugate vaccines

Vaccines are conjugates of a polysaccharide obtained from infectious agents and a protein carrier (diphtheria or tetanus toxoid). Polysaccharides antigens have a weak immunogenicity and a weak ability to form immunological memory. binding of polysaccharides to a protein carrier, well recognized by the immune system, sharply enhances the immunogenic properties of the conjugate and causes protective immunity.

Virosomal vaccines

Virosomal vaccines contain an inactivated virosomal complex associated with highly purified protective antigens. Virosomes perform the functions of an antigen carrier and an adjuvant, enhancing an immune response capable of inducing both humoral and cellular immunity.

Artificial Adjuvant Vaccines

The principle of creating such vaccines is to use natural antigens of infectious agents and synthetic carriers. One of the variants of such vaccines consists of a protein antigen of the virus and an artificial stimulant (for example, polyoxidonium), which has pronounced adjuvant (increasing the immunogenicity of antigens) properties.

Combined vaccines (associated polyvaccines)

These vaccines are a mixture of strains different types pathogens or their antigens for the prevention of two or more infections. When developing combined vaccines, the compatibility of not only antigenic components, but also their various additives (adjuvants, preservatives, stabilizers, etc.) is taken into account. These are various types of vaccines containing several components. Adverse Reactions of the organism on associated vaccines appear, as a rule, somewhat more often than on monovaccines, but they allow to create protection of the vaccinated against several infectious diseases in a short time.

The urgent task of modern vaccinology is the constant improvement of vaccine preparations, approaches to their use, testing regimens, dosages, methods and timing of administration among different age groups.

The peculiarities of the vaccine production technology, as well as the mechanism of their action in the formation of immunity, must be taken into account when organizing and conducting all stages of clinical trials.

Before the start of the clinical research, the choice of territories and contingents for the planned research should be clearly justified. for this purpose, it is necessary to conduct a retrospective epidemiological analysis of an infectious disease in a certain area among the population included in the clinical trial protocol. Based on the results of the epidemiological analysis, groups of volunteers are selected by age, sex, social characteristics, including territorial and seasonal fluctuations in the incidence, which is extremely necessary when planning clinical trials and determining the safety and efficacy of various types of vaccines.

Read also

• General provisions for conducting clinical trials of vaccines
• Clinical Trials of Inactivated Influenza Vaccines
• Features of clinical trials of vaccines against HIV / AIDS
• Features of clinical trials of vaccines against especially dangerous infections
• Features of clinical trials of vaccines against measles, mumps and rubella

All kinds of viruses and infections invariably rank first among the causes of the disease. The consequences of viral and infectious diseases can be quite severe. That is why in the developed countries of the world a lot is paid to the prevention of infectious diseases. Unfortunately, in the arsenal modern medicine there are few methods that can effectively protect the body from infections. The main weapons in the arsenal of modern medicine are preventive vaccinations, or vaccination.

What are vaccines and how do they protect people from disease?

In a dispute, the truth was born

The word "vaccine" comes from the Latin word vacca - "cow". In 1798, the English physician Edward Jenner first carried out a medical vaccination: he injected the contents of a cow's pox into an incision in the skin of an eight-year-old boy. Thanks to this, the child did not get sick with smallpox.

At the beginning of the twentieth century, the Russian scientist Ilya Mechnikov described his scientific experiment: he stuck a rose thorn into a starfish, and after a while the thorn disappeared. This is how phagocytes were discovered - special cells that destroy biological particles foreign to the body.

German scientist Paul Ehrlich argued with Mechnikov. He argued that the main role in the defense of the body belongs not to cells, but to antibodies - specific molecules that are formed in response to the introduction of an aggressor.

This scientific controversy is directly related to the study of the mechanism immunity (from Latin immunitas - liberation, getting rid of something). In short, immunity is the body's immunity to infectious agents and foreign substances. Bitter scientific rivals Mechnikov and Ehrlich shared the Nobel Prize in Physiology or Medicine in 1908. Both turned out to be right: phagocytes are a component of innate immunity, and antibodies are acquired, which arises as a result of a previous illness or the introduction of a vaccine into the body.

Immunity vaccination

The effect of vaccination is based on the fact that the human body, upon penetration of antigenic "outsiders", develops antibodies to them - that is, forms acquired immunity, due to which the body does not allow the multiplication of "enemy" cells in the body. The main active component of the vaccine - the substance used for vaccination - is an immunogen, that is, structures similar to the components of the pathogen responsible for the development of immunity.

The discovery of the vaccination method allowed humanity to achieve incredible results in the fight against infections. Poliomyelitis, smallpox, scarlet fever, measles have practically disappeared in the world; the incidence of diphtheria, rubella, whooping cough and other dangerous infectious diseases... Vaccinations against some diseases give lifelong immunity, which is why they are given in the first years of a child's life.

Choosing a vaccine - for example, for vaccination against the influenza virus - should not be guided solely by imported goods as a higher quality and "environmentally friendly". All vaccines, regardless of the country of their production, contain preservatives. An indication of the need for their presence is contained in the WHO recommendations. The purpose of preservatives is to ensure the sterility of the drug in the event of microcracks on the package during transportation and storage of an opened primary multi-dose package.

Experts believe that vaccines are useful for the child's immune system as a kind of "additional information". From the fourth day of life to four or five years children's organism is in the physiological state of "immunological learning", that is, it collects a maximum of information about the surrounding microbial and antigenic (that is, genetically alien) world. The entire immune system is tuned in to this learning process, and vaccinations as a "message delivery" option are much easier to carry and prove to be more effective than at a later time. Some vaccinations (for example, against whooping cough) can only be given before the age of 3 years, because then the body will react too violently to the vaccine.

Long-term observations have shown that vaccination is not always effective. Vaccines lose their quality if stored improperly. But even if the storage conditions were respected, there is always a possibility that the stimulation of the immune system will not occur. There is no "response" to vaccination in 5-15% of cases.

Be careful! Opponents of vaccinations should remember that the consequences of viral infections can be much more serious than just "childhood" illnesses. For example, after measles, the likelihood of developing type 1 diabetes mellitus (insulin-dependent) is quite high, and severe forms of encephalitis (inflammation of the brain) can be a complication of rubella.

What are we vaccinated with?

The effectiveness of vaccine prophylaxis depends on two components: the quality of the vaccine and the health of the vaccinated. The question of the necessity and usefulness of vaccinations is today considered controversial. Article 11 of the law of the Russian Federation "infectious diseases" approves the complete voluntariness of vaccination, based on awareness of the quality and origin of the vaccine, about all the advantages and possible risks vaccinations. Children under 15 can only be vaccinated with parental permission. The doctor has no right to order, the doctor can only recommend.

Vaccines of various types, types and purposes are available today.

• Live vaccine - a drug based on a weakened living microorganism that has lost its ability to cause disease, but is capable of multiplying in the body and stimulating the immune response. This group includes vaccines against measles, rubella, polio, influenza, etc. Positive properties of a live vaccine: according to the mechanism of action on the body, it resembles a "wild" strain, it can take root in the body and maintain immunity for a long time, regularly displacing the "wild" strain. A small dose is sufficient for vaccination (usually a single vaccination). Negative properties: live vaccines are difficult to biocontrol, sensitive to action high temperatures and require special storage conditions.
• Killed (inactivated) vaccine- a preparation that contains a killed pathogenic microorganism - in whole or in part. The pathogen is killed by physical methods (temperature, radiation, ultraviolet light) or chemical (alcohol, formaldehyde). The inactivated group includes vaccines against tick-borne encephalitis, plague, typhoid fever, viral hepatitis A, and meningococcal infection. Such vaccines are reactogenic, they are little used (whooping cough, against hepatitis A).
• Chemical vaccine - a drug that is created from antigenic components extracted from a microbial cell. The chemical group includes vaccines against diphtheria, hepatitis B, rubella, whooping cough.
• Recombinant (vector, biosynthetic) vaccine - a drug obtained by genetic engineering methods using recombinant technology. The genes of a virulent microorganism responsible for protective antigens are inserted into any harmless microorganism (for example, a yeast cell), which, upon cultivation, produces and accumulates the corresponding antigen. The recombinant group includes vaccines against viral hepatitis B, rotavirus infection, herpes simplex virus.
• Associated (polyvalent) vaccine - a preparation containing components of several vaccines. To the group polyvalentthese include the adsorbed diphtheria-tetanus pertussis vaccine (DTP vaccine), tetravaccine (vaccines against typhoid, paratyphoid A and B, and tetanus toxoid), and ADS vaccine (diphtheria-tetanus toxoid).