The discovery of vaccination marked the beginning of a new era in the fight against disease.
The composition of the grafting material includes killed or greatly weakened microorganisms or their components (parts). They serve as a kind of dummy that trains the immune system to give the correct response to infectious attacks. The substances that make up the vaccine (inoculation) are not capable of causing a full-blown disease, but can enable the immune system to remember characteristic features microbes and when encountering a real pathogen, quickly identify and destroy it.
The production of vaccines became widespread at the beginning of the twentieth century, after pharmacists learned to neutralize bacterial toxins. The process of weakening potential infectious agents is called attenuation.
Today medicine has more than 100 types of vaccines against dozens of infections.
Based on their main characteristics, immunization preparations are divided into three main classes.
- Live vaccines. Protects against polio, measles, rubella, influenza, mumps, chickenpox, tuberculosis, rotavirus infection. The basis of the drug is weakened microorganisms - pathogens. Their strength is not enough to cause significant illness in the patient, but it is enough to develop an adequate immune response.
- Inactivated vaccines. Flu shots typhoid fever, tick-borne encephalitis, rabies, hepatitis A, meningococcal infection, etc. Contains dead (killed) bacteria or their fragments.
- Anatoxins (toxoids). Specially treated bacterial toxins. Based on them, vaccination material is made against whooping cough, tetanus, and diphtheria.
In recent years, another type of vaccine has appeared - molecular. The material for them is recombinant proteins or their fragments synthesized in laboratories using methods genetic engineering(recombinant vaccine against viral hepatitis IN).
Schemes for the production of certain types of vaccines
Live bacterial
The regimen is suitable for BCG and BCG-M vaccines.
Live antiviral
The scheme is suitable for the production of vaccines against influenza, rotavirus, herpes degrees I and II, rubella, and chickenpox.
Substrates for growing viral strains during vaccine production can be:
- chicken embryos;
- quail embryonic fibroblasts;
- primary cell cultures (chicken embryonic fibroblasts, Syrian hamster kidney cells);
- continuous cell cultures (MDCK, Vero, MRC-5, BHK, 293).
The primary raw material is purified from cellular debris in centrifuges and using complex filters.
Inactivated antibacterial vaccines
- Cultivation and purification of bacterial strains.
- Biomass inactivation.
- For split vaccines, microbial cells are disintegrated and antigens are precipitated, followed by chromatographic isolation.
- For conjugate vaccines, antigens (usually polysaccharides) obtained during previous processing are brought closer to the carrier protein (conjugation).
Inactivated antiviral vaccines
- Substrates for growing viral strains in the production of vaccines can be chicken embryos, quail embryonic fibroblasts, primary cell cultures (chicken embryonic fibroblasts, Syrian hamster kidney cells), continuous cell cultures (MDCK, Vero, MRC-5, BHK, 293). Primary purification to remove cellular debris is carried out by ultracentrifugation and diafiltration.
- Ultraviolet light, formalin, and beta-propiolactone are used for inactivation.
- In the case of split or subunit vaccines, the intermediate product is exposed to a detergent to destroy the viral particles, and then specific antigens are isolated by thin chromatography.
- Human serum albumin is used to stabilize the resulting substance.
- Cryoprotectants (in lyophilisates): sucrose, polyvinylpyrrolidone, gelatin.
The scheme is suitable for the production of vaccination material against hepatitis A, yellow fever, rabies, influenza, polio, tick-borne and Japanese encephalitis.
Anatoxins
For decontamination harmful effects toxins using methods:
- chemical (treatment with alcohol, acetone or formaldehyde);
- physical (heating).
The scheme is suitable for the production of vaccines against tetanus and diphtheria.
According to the World Health Organization (WHO), the share of infectious diseases accounts for 25% of total number deaths on the planet every year. That is, infections still remain on the list of the main reasons that end a person’s life.
One of the factors contributing to the spread of infectious and viral diseases, are migration of population flows and tourism. The movement of human masses around the planet affects the level of health of the nation, even in such highly developed countries as the USA, the UAE and the European Union.
Based on materials: “Science and Life” No. 3, 2006, “Vaccines: from Jenner and Pasteur to the present day,” Academician of the Russian Academy of Medical Sciences V.V. Zverev, Director of the Research Institute of Vaccines and Serums named after. I. I. Mechnikova RAMS.
Ask a question to a specialist
Question for vaccination experts
Questions and answers
Is the Menugate vaccine registered in Russia? At what age is it approved for use?
Yes, the vaccine is registered - against meningococcus C, now there is also a conjugate vaccine, but against 4 types of meningococci - A, C, Y, W135 - Menactra. Vaccinations are carried out from 9 months of life.
The husband transported the RotaTek vaccine to another city. When buying it at the pharmacy, the husband was advised to buy a cooling container, and before the trip, freeze it in the freezer, then tie the vaccine and transport it that way. Travel time took 5 hours. Is it possible to administer such a vaccine to a child? It seems to me that if you tie the vaccine to a frozen container, the vaccine will freeze!
Answered by Kharit Susanna Mikhailovna
You are absolutely right if there was ice in the container. But if there was a mixture of water and ice-vaccine shouldn't freeze. However, live vaccines, which include rotavirus, do not increase reactogenicity at temperatures below 0, unlike non-live ones, and, for example, for live polio, freezing to -20 degrees C is allowed.
My son is now 7 months old.
At 3 months he developed Quincke's edema on Malyutka milk formula.
Hepatitis vaccination was given in the maternity hospital, the second at two months and the third yesterday at seven months. The reaction is normal, even without fever.
But we were verbally given a medical certificate for the DPT vaccination.
I am for vaccinations!! And I want to get vaccinated with DTP. But I want to make INFANRIX HEXA. We live in Crimea!!! It is nowhere to be found in Crimea. Please advise what to do in this situation. Maybe there is a foreign analogue? I absolutely don’t want to make it free. I want a high-quality cleaned one, so that there is as little risk as possible!!!
Infanrix Hexa contains a component against hepatitis B. The child is fully vaccinated against hepatitis. Therefore, as foreign analogue DPT vaccine can be given Pentaxim. In addition, it should be said that angioedema on formula milk is not a contraindication to the DTP vaccine.
Tell me, please, on whom and how are vaccines tested?
Polibin Roman Vladimirovich answers
Like all medications vaccines undergo preclinical studies (in the laboratory, on animals), and then clinical studies on volunteers (on adults, and then on adolescents, children with the permission and consent of their parents). Before authorization for use in the national vaccination calendar, studies are carried out on a large number of volunteers, for example, the vaccine against rotavirus infection was tested on almost 70,000 in different countries of the world.
Why is the composition of vaccines not presented on the website? Why is the annual Mantoux test still carried out (often not informative), and not a blood test, for example, a quantiferon test? How can one assert the immune response to an administered vaccine if no one yet knows in principle what immunity is and how it works, especially if we consider each individual person?
Polibin Roman Vladimirovich answers
The composition of vaccines is set out in the instructions for the drugs.
Mantoux test. According to Order No. 109 “On improving anti-tuberculosis measures in the Russian Federation” and Sanitary regulations SP 3.1.2.3114-13 "Prevention of tuberculosis", despite the availability of new tests, children need to have the Mantoux test done annually, but since this test can give false positive results, then if tuberculosis infection and active tuberculosis infection are suspected, the Diaskin test is performed. The Diaskin test is highly sensitive (effective) for detecting active tuberculosis infection (when mycobacteria are multiplying). However, phthisiatricians do not recommend completely switching to the Diaskin test and not doing the Mantoux test, since it does not “catch” early infection, and this is important, especially for children, since preventing the development of local forms of tuberculosis is effective precisely in the early period of infection. In addition, infection with Mycobacterium tuberculosis must be determined to decide on BCG revaccination. Unfortunately, there is not a single test that would answer the question with 100% accuracy of whether there is a mycobacterial infection or disease. The quantiferon test also detects only active forms of tuberculosis. Therefore, if you suspect an infection or disease ( positive reaction Mantoux, contact with the patient, presence of complaints, etc.) complex methods are used (diaskin test, quantiferon test, radiography, etc.).
As for “immunity and how it works,” immunology is currently a highly developed science and much, in particular with regard to processes during vaccination, is open and well studied.
The child is 1 year and 8 months old, all vaccinations were given in accordance with the vaccination calendar. Including 3 Pentaxim and revaccination at one and a half years, also Pentaxim. At 20 months you should be diagnosed with polio. I’m always very worried and careful when choosing the right vaccinations, and now I’ve scoured the entire Internet, but I still can’t decide. We always gave an injection (in Pentaxim). And now the drops are talking. But the drops are a live vaccine, I’m afraid of various side effects and I think it’s better to play it safe. But I read that polio drops produce more antibodies, including in the stomach, that is, they are more effective than an injection. I'm confused. Explain, is the injection less effective (imovax-polio, for example)? Why are such conversations being held? I'm afraid the drops have, although minimal, the risk of complications in the form of illness.
Polibin Roman Vladimirovich answers
Currently National calendar Vaccinations in Russia involve a combined vaccination regimen against polio, i.e. only the first 2 injections with inactivated vaccine and the rest with oral polio vaccine. This is due to the fact that it completely eliminates the risk of developing vaccine-associated polio, which is possible only during the first and in a minimal percentage of cases during the second administration. Accordingly, if there are 2 or more vaccinations against polio with an inactivated vaccine, complications with live polio vaccine are excluded. Indeed, it was believed and is recognized by some experts that the oral vaccine has advantages, since it forms local immunity on the intestinal mucosa, in contrast to IPV. However, it has now become known that the inactivated vaccine, to a lesser extent, also forms local immunity. In addition, 5 injections of polio vaccine, both oral live and inactivated, regardless of the level of local immunity on the intestinal mucous membranes, completely protect the child from paralytic forms of polio. In connection with the above, your child needs to do the fifth OPV vaccination or IPV.
It should also be said that today the World Health Organization’s global plan to eradicate polio in the world is being implemented, which involves a complete transition of all countries to an inactivated vaccine by 2019.
Our country already has a very long history of using many vaccines - are there long-term studies of their safety and is it possible to get acquainted with the results of the impact of vaccines on generations of people?
Olga Vasilievna Shamsheva answers
Over the past century, people's life expectancy has increased by 30 years, of which people gained 25 additional years of life through vaccination. More people survive, they live longer and have a better quality of life due to the fact that disability due to infectious diseases has decreased. This is a general response to how vaccines affect generations of people.
The World Health Organization (WHO) website has extensive factual material on the beneficial effects of vaccination on the health of individuals and humanity as a whole. Let me note that vaccination is not a belief system, it is an area of activity based on a system scientific facts and data.
On what basis can we judge the safety of vaccination? Firstly, side effects and adverse events are recorded and identified and their cause-and-effect relationship with the use of vaccines is determined (pharmacovigilance). Secondly, important role Post-marketing studies (possible delayed adverse effects of vaccines on the body) conducted by companies holding registration certificates play a role in tracking adverse reactions. Finally, the epidemiological, clinical and socioeconomic effectiveness of vaccination is assessed through epidemiological studies.
As far as pharmacovigilance is concerned, our pharmacovigilance system in Russia is just being formed, but is demonstrating very high rates of development. In just 5 years, the number of registered reports of adverse reactions for medicines in the “Pharmaconadzor” subsystem of the AIS of Roszdravnadzor increased 159 times. 17,033 complaints in 2013 versus 107 in 2008. For comparison, in the United States, data is processed about 1 million cases per year. The pharmacovigilance system allows you to monitor the safety of drugs; statistical data is accumulated, on the basis of which the instructions for medical use of the drug may change, the drug may be withdrawn from the market, etc. This ensures patient safety.
And according to the law “On Treatment medicines» from 2010, doctors are required to report to federal regulatory authorities about all cases of side effects of drugs.
Currently, humanity knows such types of vaccines that help prevent the development of dangerous infectious diseases and other pathologies. The injection can help the immune system create resistance to certain types of diseases.
Vaccine subgroups
There are 2 types of vaccinations:
- alive
- inactivated.
Live – contain a mixture of strains of various weakened microorganisms. The loss of pathogenic properties is assigned to vaccine strains. Their action begins in the place where the drug was administered. When vaccinated using this method, a strong immunity is created that is able to retain its properties. long time. Immunopreparations with live microorganisms are used against the following diseases:
- pigs
- rubella
- tuberculosis
- polio.
There are a number of disadvantages of living complexes:
- Difficult to dose and combine.
- In case of immunodeficiency, it should not be used categorically.
- Unstable.
- The effectiveness of the drug is reduced due to the naturally circulating virus.
- During storage and transportation, safety precautions must be observed.
Inactivated - or killed. They are specially grown using inactivation. As a result, damage to structural proteins occurs minimally. Therefore, treatment with alcohol, phenol or formaldehyde is used. At a temperature of 56 degrees, the inactivation process takes place for 2 hours. Killed types of vaccines have a shorter period of action compared to live types.
Advantages:
- responds well to dosage and combination;
- vaccine-associated diseases do not occur;
- They are allowed to be used even in people with immunodeficiency.
Flaws:
- great amount“ballast” components and others that are not able to participate in creating the body’s defenses;
- Allergy or toxic effects may occur.
There is a classification of inactivated drugs. Biosynthetic – the second name is recombinant. They contain genetic engineering products. Often used in combination with other drugs to strengthen the immune system against several diseases at once. Considered safe and effective. The most common injection is given against hepatitis B.
Chemical - receive antigens from microbial cells. Only those cells that can affect the immune system are used. Polysaccharide and pertussis injections are chemical.
Corpuscular are bacteria or viruses that have been inactivated with formaldehyde, alcohol, or heat.
DTP and tetracoccus vaccinations, injections against hepatitis A and influenza belong to this group.
All inactivated drugs can be produced in 2 states: liquid and dry.
- The classification of vaccine complexes follows a different principle. They are distinguished depending on the number of antigens, that is, mono- and polyvaccines.
- Depending on the composition of the species, they are divided into:
- viral
bacterial
- rickettsial.
- Now they are developing at an accelerated pace:
- synthetic
anti-idiotypic
recombinant.
Anatoxins – are produced from neutralized exotoxins. Typically, aluminum hydroxide is used to absorb toxoids. As a result, antibodies appear in the body that act against toxoids. As a result, their action does not exclude the penetration of bacteria. Toxoids are used against diphtheria and tetanus. 5 years is the maximum validity period.
DPT – diphtheria, whooping cough, tetanus
The characteristic of this injection is that it acts as a barrier to severe infections. The drug contains antigens that can form bodies that prevent the penetration of infection. Types of DTP vaccine DPT – adsorbed pertussis, diphtheria and tetanus vaccine. The injection helps protect a person from the most dangerous diseases. They begin to vaccinate at a very young age. The baby’s body cannot cope with the disease on its own, so they need to be protected. The first injection is given at 2 or 3 months. At
DPT vaccinations
- the reaction may be different, which is why some parents are wary of doing it. Komarovsky: “The risk of complications after vaccination is much lower than if complications arise from an emerging disease.” There are several certified immunodrug options. The World Health Organization allows all of these varieties. The DTP classification is as follows: Whole cell vaccine – used for children who do not have serious illnesses. Contains
- whole cell a microbe that can exhibit a strong reaction to the body. Acellular – weakened form. Used for children if they are not allowed to use full form. This category includes children who have already had whooping cough, children
Manufacturers also now offer different forms of the DTP drug. Their characteristics indicate that any one can be used without fear. What drugs do manufacturers offer?
- Liquid form. Usually produced by a Russian manufacturer. The child is first vaccinated at 3 months. The subsequent vaccination is done after 1.5 months.
- Infanrix. Its advantage is that it can be used in combination with other vaccines.
- IPV. This DTP vaccination with polio.
- Infanrix hexa. The composition includes components that help fight diphtheria, whooping cough, tetanus, hepatitis B, polio and Haemophilus influenzae.
- Pentaxim. Vaccination together with polio and hemophilus influenzae. French vaccine.
- Tetracoccus Also a French suspension. Used to prevent DPT and polio.
Doctor Komarovsky: “I consider Pentaxim the safest and effective vaccination, is capable of giving a good response to the disease.”
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Vaccination
Different clinics may offer several types of vaccinations. There are several methods of administration. You can choose any one. Methods:
- intradermal
- subcutaneous
- intranasal
- enteral
- cutaneous
- combined
- inhalation
Subcutaneous, intradermal and cutaneous are considered the most painful. When vaccinated using such methods, the integrity of the skin is destroyed.
Often these methods are painful. To reduce pain, a needle-free method is used. Under pressure, the jet is injected into the skin or deep into the cells. Using this method, sterility is maintained many times higher than with other methods.
Methods that do not involve touching the skin are very popular with children. For example, the polio vaccine comes in pill form. When vaccinating against influenza, the intranasal method is used. But in this case it is important to prevent leakage of the drug. Inhalations are the most effective method
. Helps vaccinate a large number of people in a short time. This method of vaccination is not yet so widespread, but may be used everywhere in the near future. Vaccines – for immunoprophylaxis of infectious diseases by developing an active immune response to a specific pathogen. Vaccines help create long-term resistance of the body to a certain type of pathogenic microbial bodies. Vaccines help carry out routine and emergency prevention of infectious diseases, which is called vaccination. This effective and at the same time simple technique quickly gained respect among specialists. It serves to prevent epidemics that threaten the health of all humanity.
The essence of vaccination
Vaccination is a plan of action aimed at protecting the body of an adult or child from harmful microorganisms. The method is based on the ability of immunobiological solutions to train the immune system by remembering infectious agents or toxoids and instantly destroying them during subsequent infection.
Vaccination is a multi-level action, conditionally divided into several stages:
- identification of persons for whom vaccination is recommended;
- choice of vaccine preparation (live, inactivated, toxoid);
- scheduling vaccinations;
- administration of vaccines according to the approved plan;
- control of results;
- prevention and treatment of possible post-vaccination complications or adverse reactions (pathological reactions are most often observed after the administration of tetanus toxoids, diphtheria bacillus in combination with a pertussis component).
Modern vaccines are highly effective and reliable preparations with specific antigens (microorganisms, their fragmentary parts, toxoids) for the prevention of dangerous infectious pathologies and other diseases. They are created through the use of modern genetic engineering developments. They contribute to the rapid formation of protective resistance to various types of painful conditions. Vaccines can be used for vaccine therapy of infection after patient contact with a potential pathogen.
Basic methods of immunization
Vaccination methods depend on the method of administering a prophylactic solution with antigens to a person. IN clinical practice A number of these techniques are used. Depending on their characteristics, it is determined how the immune response will be instilled:
- The intramuscular method involves the need for an injection into the muscles of the thigh, delta ( shining example– vaccination with DTP toxoids);
- subcutaneous vaccinations are placed in the subscapular or shoulder region (this vaccination option is characterized by increased effectiveness, low allergenicity, and ease of use);
- intradermal vaccine injections are carried out with a live vaccine (BCG, plague, tularemia, Q fever);
- the inhalation method is used for emergency care (vaccines against tetanus, influenza, diphtheria intoxication, rubella, and tuberculosis are administered this way);
- oral administration is one of the most convenient immunization options, since the drugs are administered through the mouth in the form of drops (rabies vaccination, polio vaccine).
Intramuscular, subcutaneous, and intradermal vaccinations are the most unpleasant for patients, as they are administered by puncturing the skin, causing pain to the person. For elimination discomfort Today it is recommended to administer drugs in the form of aerosols or orally. In addition to being painless, these methods of preventive immunization are characterized by high sterility and a small number of post-vaccination complications.
Vaccine classification
Depending on the origin, there are four types of vaccines:
- live vaccine consisting of weakened pathogens;
- inactivated suspension, which includes killed microorganisms or their fragments;
- a chemical vaccine contains highly purified antigens;
- a synthetic vaccine synthesized using advanced genetic engineering technologies in the field of microbiology.
Some vaccines consist of components that promote the development of immunity against one disease (single-drug). Others include active ingredients, protecting against several pathologies at once, therefore they are called combined vaccines.
If we take into account the type of antigens involved in creating the vaccine, then it is easy to identify the types of solutions:
- containing whole microbial cellular elements (live or inactivated vaccine);
- including fragments of microbial units;
- consisting of microorganism toxins (anatoxins);
- created on the basis of synthetic antigens;
- obtained by synthesizing antigens using the achievements of genetic engineering.
What is a live vaccine?
A classic live vaccine is a means of immunoprophylaxis, in the manufacturing process of which not completely killed, but weakened strains of pathogenic agents were used. These drugs have pronounced immunogenic properties, but are not able to provoke the development of the disease with its inherent symptoms.
The introduction of this type of vaccine provokes the formation of protective complexes related to persistent cellular, humoral or secretory immunity. These suspensions often cause complications, unlike toxoids, which are much better accepted by the immune system.
Advantages and disadvantages
Among the advantages of vaccines created using live, that is, not killed, microbial agents are:
- high efficiency;
- rapid formation of immune complexes;
- the absence of any preservatives in the composition of the drug;
- usage minimum concentrations vaccines;
- the possibility of using different grafting methods;
- activation of different types of immunity;
- low cost and availability.
The live vaccine, in addition to its advantages, also has its disadvantages. The main disadvantages include:
- the ability to provoke the development of pathology when vaccinating a patient with a weakened immune system;
- vaccines based on live pathogens are unstable and quickly lose their positive traits during temperature changes (people face unwanted effects immunization precisely after the introduction of low-quality vaccines);
- a live vaccine cannot be combined with other means of vaccine prevention (such actions are fraught with loss of effect from the drugs or the appearance of allergies).
Types of live vaccine suspensions
Immunologists take into account the properties of vaccine components with live microbes, dividing them into attenuated and divergent suspensions. Attenuated or weakened solutions are created on the basis of pathogenic strains with a sharply reduced ability to cause disease, but which have not lost their immunogenicity. The immune system responds to the introduction of these vaccines by forming antibodies to the infection, preventing it from developing in the future. The main part of attenuated vaccines are drugs for the prevention of rabies, influenza, Q fever, mumps, measles, rubella and various strains of adenovirus.
The second group is vaccines made from natural (divergent) strains of microorganisms that have low virulence in relation to the body, but are capable of stimulating the synthesis protective antibodies. An example of such solutions are preventative vaccines from smallpox made from viruses cowpox.
Features of the influenza vaccine
Flu is difficult viral disease, which annually affects hundreds of thousands of our fellow citizens, causes a huge number of complications and can even cause death in patients. The only way to warn dangerous infection– timely use of a vaccine that helps create short-term immunity, which is enough to prevent a seasonal wave of infection.
The main indications for vaccination include:
- old age (60 years and older);
- the patient has chronic diseases organs of the bronchopulmonary and cardiovascular systems;
- patients suffering from severe pathologies of the liver and kidneys, people with metabolic disorders, immunosuppression;
- pregnancy after 12 weeks.
Main types of anti-influenza solutions
Vaccines that protect against influenza are either live or inactivated. There are no anti-influenza toxoids. Inactivated suspensions are divided into:
- killed vaccine, which contains undestroyed but highly purified virions of the pathogen;
- split vaccine (split), consisting of destroyed viral agents;
- A subunit vaccine contains fragmented viral envelope proteins capable of inducing immune cells.
IN medical practice Vaccines made from subunit solutions are often used, since they lack chicken protein and are adapted for humans. The most famous representatives of this series are the popular vaccines Agrippal and Influvac.
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The arsenal of modern immunoprophylaxis includes several dozen immunoprophylactic agents.
There are currently two types of vaccines:
- traditional (first and second generation) and
- third generation vaccines designed based on biotechnology methods.
First and second generation vaccines
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Among first and second generation vaccines distinguish:
- alive,
- inactivated (killed) and
- chemical vaccines.
Live vaccines
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To create live vaccines, microorganisms (bacteria, viruses, rickettsia) with weakened virulence that arose in natural conditions or artificially in the process of strain selection. The effectiveness of a live vaccine was first shown by the English scientist E. Jenner (1798), who proposed for immunization against smallpox a vaccine containing the causative agent of cowpox, which is low-virulent for humans; the name “vaccine” comes from the Latin word vassa - cow. In 1885, L. Pasteur proposed a live vaccine against rabies from a weakened (attenuated) vaccine strain. To reduce virulence, French researchers A. Calmette and C. Guérin cultivated mycobacterium tuberculosis for a long time in an environment unfavorable for the microbe. bullish type, which are used to obtain live BCG vaccine.
In Russia, both domestic and foreign live attenuated vaccines are used. These include vaccines against polio, measles, mumps, rubella, and tuberculosis, which are included in the preventive vaccination calendar.
Vaccines against tularemia, brucellosis, anthrax, plague, yellow fever, influenza. Live vaccines create intense and long-lasting immunity.
Inactivated vaccines
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Inactivated (killed) vaccines are preparations prepared using industrial strains of the pathogens of the corresponding infections and preserving the corpuscular structure of the microorganism. (The strains have full antigenic properties.) There are various methods inactivation, the main requirements for which are reliability of inactivation and minimal damaging effect on antigens of bacteria and viruses.
Historically, heating was considered the first method of inactivation. (“warmed vaccines”).
The idea of “warmed vaccines” belongs to V. Collet and R. Pfeiffer. Inactivation of microorganisms is also achieved under the influence of formaldehyde, formaldehyde, phenol, phenoxyethanol, alcohol, etc.
The Russian vaccination calendar includes vaccination with killed whooping cough vaccine. Currently, the country uses (along with live) inactivated polio vaccine.
In healthcare practice, along with live ones, killed vaccines against influenza, tick-borne encephalitis, typhoid fever, paratyphoid fever, brucellosis, rabies, hepatitis A, meningococcal infection, herpes infection, Q fever, cholera and other infections are also used.
Chemical vaccines
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Chemical vaccines contain specific antigenic components extracted from bacterial cells or toxins different ways(extraction with trichloroacetic acid, hydrolysis, enzymatic digestion).
The highest immunogenic effect is observed with the introduction of antigenic complexes obtained from the shell structures of bacteria, for example, the Vi-antigen of typhoid and paratyphoid pathogens, the capsular antigen of the plague microorganism, antigens from the shells of the pathogens of whooping cough, tularemia, etc.
Chemical vaccines have a less pronounced effect side effect, they are reactogenic and retain their activity for a long time. Among the drugs in this group, cholerogens are used in medical practice - toxoid, highly purified antigens of meningococci and pneumococci.
Anatoxins
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To create artificial active immunity Toxoids are used against infectious diseases caused by microorganisms that produce exotoxin.
Anatoxins are neutralized toxins that have retained antigenic and immunogenic properties. Neutralization of the toxin is achieved by exposure to formaldehyde and prolonged exposure in a thermostat at a temperature of 39–40 ° C. The idea of neutralizing the toxin with formalin belongs to G. Ramon (1923), who proposed diphtheria toxoid for immunization. Currently, diphtheria, tetanus, botulinum and staphylococcal toxoids are used.
In Japan, an acellular precipitated purified pertussis vaccine has been created and is being studied. It contains lymphocytosis-stimulating factor and hemagglutinin as toxoids and is significantly less reactogenic and at least as effective as corpuscular killed pertussis vaccine (which is the most reactogenic part of the widely used DTP vaccine).
Third generation vaccines
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Currently, traditional vaccine manufacturing technologies continue to be improved and vaccines are being successfully developed taking into account the achievements of molecular biology and genetic engineering.
The impetus for the development and creation of third-generation vaccines was due to the limited use of traditional vaccines for the prevention of a number of infectious diseases. First of all, this is due to pathogens that are poorly cultivated in in vitro and in vivo systems (hepatitis viruses, HIV, malaria pathogens) or have pronounced antigenic variability (influenza).
Third generation vaccines include:
- synthetic vaccines,
- genetic engineering And
- anti-idiotypic vaccines.
Artificial (synthetic) vaccines
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Artificial (synthetic) vaccines are a complex of macromolecules that carry several antigenic determinants of various microorganisms and are capable of immunizing against several infections, and a polymer carrier is an immunostimulant.
The use of synthetic polyelectrolytes as an immunostimulant can significantly increase the immunogenic effect of the vaccine, including in individuals carrying low response Ir genes and strong suppression Is genes, i.e. in cases where traditional vaccines are ineffective.
Genetically engineered vaccines
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Genetically engineered vaccines are developed based on antigens synthesized in recombinant bacterial systems (E. coli), yeast (Candida) or viruses (vaccinia virus). This type of vaccine may be effective in immunoprophylaxis of viral hepatitis B, influenza, herpes infection, malaria, cholera, meningococcal infection, and opportunistic infections.
Anti-idiotypic vaccines
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Among the infections for which vaccines already exist or the use of new generation vaccines is planned, hepatitis B should be noted first of all (vaccination was introduced in accordance with the order of the Ministry of Health of the Russian Federation No. 226 of 06/08/96 in the vaccination calendar).
Promising vaccines include vaccines against pneumococcal infection, malaria, HIV infection, hemorrhagic fevers, acute respiratory viral infections (adenovirus, respiratory syncytial viral infection), intestinal infections(rotavirus, helicobacteriosis), etc.
Single and combination vaccines
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Vaccines may contain antigens from one or more pathogens.
Vaccines containing antigens of the causative agent of one infection are called monovaccines(cholera, measles monovaccine).
Widely used associated vaccines consisting of several antigens and allowing vaccination against several infections simultaneously, di- And trivaccines. These include adsorbed pertussis-diphtheria-tetanus (DTP) vaccine, typhoid-paratyphoid-tetanus vaccine. Adsorbed diphtheria-tetanus (DT) divaccine is used, which is vaccinated in children after 6 years of age and adults (instead of DTP vaccination).
Live associated vaccines include the measles, rubella, and mumps vaccine (MMR). A combined TTK and chickenpox vaccine is being prepared for registration.
Ideology of creation combined vaccines is included in the World Vaccine Initiative program, the ultimate goal of which is to create a vaccine that could protect against 25–30 infections, administered once orally at the very early age and would not cause side effects.
Over the centuries, humanity has experienced more than one epidemic that has claimed the lives of many millions of people. Thanks to modern medicine, it has been possible to develop drugs that allow us to avoid many deadly diseases. These drugs are called “vaccine” and are divided into several types, which we will describe in this article.
What is a vaccine and how does it work?
The vaccine is medical drug containing killed or weakened pathogens various diseases or synthesized proteins of pathogenic microorganisms. They are introduced into the human body to create immunity to a certain disease.
The introduction of vaccines into the human body is called vaccination, or inoculation. The vaccine, entering the body, encourages the human immune system to produce special substances to destroy the pathogen, thereby forming a selective memory for the disease. Subsequently, if a person becomes infected with this disease, his immune system will quickly counteract the pathogen and the person will not get sick at all or suffer light form diseases.
Vaccination methods
Immunobiological drugs can be administered in various ways according to the instructions for vaccines, depending on the type of drug. There are the following methods of vaccination.
- Vaccine administration intramuscularly. The vaccination site for children under one year of age is the upper surface of the middle thigh, and for children over 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: DTP, ADS, against viral hepatitis B and influenza vaccine.
Feedback from parents suggests that infants tolerate vaccination better when top part thighs rather than the buttock. Doctors also share the same opinion, due to the fact that there may be an abnormal placement of nerves in the gluteal region, 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 getting into the area. subcutaneous layer, which reduces the effectiveness of the drug.
- Subcutaneous injections are given with a thin needle under the skin in the deltoid muscle or forearm area. Example - BCG, smallpox vaccination.
- The intranasal method is applicable for vaccines in the form of ointment, cream or spray (measles, rubella vaccination).
- The oral route is when the vaccine in the form of drops is placed in the patient's mouth (poliomyelitis).
Types of vaccines
Today in my hands medical workers In the fight against dozens of infectious diseases, there are more than a hundred vaccines, thanks to which entire epidemics have been avoided and the quality of medicine has been significantly improved. Conventionally, it is customary to distinguish 4 types of immunobiological preparations:
- Live vaccine (poliomyelitis, rubella, measles, mumps, influenza, tuberculosis, plague, anthrax).
- Inactivated vaccine (against whooping cough, encephalitis, cholera, meningococcal infection, rabies, typhoid fever, hepatitis A).
- Toxoids (vaccines against tetanus and diphtheria).
- Molecular or biosynthetic vaccines (for hepatitis B).
Types of Vaccines
Vaccines can also be grouped based on their composition and method of preparation:
- Corpuscular, that is, consisting of whole microorganisms of the pathogen.
- Component or cell-free consist of parts of the pathogen, the so-called antigen.
- Recombinant: this group of vaccines includes antigens of a pathogenic microorganism introduced using genetic engineering methods into the cells of another microorganism. A 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 yeast cells.
Another criterion by which a vaccine is classified is the number of diseases or pathogens it prevents:
- Monovalent vaccines prevent only one disease (for example, the BCG vaccine against tuberculosis).
- Polyvalent or associated - for vaccination against several diseases (for example, DPT against diphtheria, tetanus and whooping cough).
Live vaccine
A live vaccine is an indispensable drug for the prevention of many infectious diseases, which is found only in corpuscular form. Characteristic feature This type of vaccine is considered to be that its main component is weakened strains of the infectious agent that are capable of multiplying, but are genetically devoid of virulence (the ability to infect the body). They help the body produce antibodies and immune memory.
The advantage of live vaccines is that still living, but weakened pathogens encourage the human body to develop long-term immunity (immunity) to a given pathogenic agent, even with a single vaccination. There are several ways to administer the vaccine: intramuscularly, under the skin, or nasal drops.
Disadvantage - gene mutation of pathogenic agents is possible, which will lead to illness in the vaccinated person. In this regard, it is contraindicated for patients with particularly weakened immune systems, namely for people with immunodeficiency and cancer patients. Requires special conditions 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 operation is based on the introduction of artificially cultivated and deprived viral pathogens into the human body.
“Killed” vaccines can be either whole-microbial (whole-viral), subunit (component) or genetically engineered (recombinant).
An important advantage of “killed” vaccines is their absolute safety, that is, there is no likelihood of the vaccinated person becoming infected and developing an infection.
Disadvantage - lower duration of immune memory compared to “live” vaccinations, also in inactivated vaccines the likelihood of developing autoimmune and toxic complications remains, and in order to achieve full immunization, several vaccination procedures are required with maintaining the required interval between them.
Anatoxins
Toxoids are vaccines created on the basis of disinfected toxins released during the life processes of certain pathogens of infectious diseases. The peculiarity of this vaccination is that it provokes the formation not of microbial immunity, but of antitoxic immunity. Thus, toxoids are successfully used to prevent those diseases in which clinical symptoms associated with a toxic effect (intoxication) resulting from biological activity pathogenic agent.
Release form: transparent liquid with sediment in glass ampoules. Shake contents before use uniform distribution toxoids.
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 and do not require special storage conditions.
The disadvantages of toxoids are that 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.
Production of live vaccines
The vaccine began to be produced en masse at the beginning of the 20th century, when biologists learned to weaken viruses and pathogenic microorganisms. Live vaccines make up about half of all preventive 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 less susceptible to a given microorganism (virus), or cultivating the pathogen in unfavorable conditions for it with exposure to physical, chemical and biological factors followed by selection of non-virulent strains. Most often, the substrate for cultivating avirulent strains is chicken embryos, primary cells (chicken or quail embryonic fibroblasts) and continuous cultures.
Obtaining “killed” vaccines
The production of inactivated vaccines differs from live ones in that they are obtained by killing rather than attenuating the pathogen. For this, only those pathogenic microorganisms and viruses that have the greatest virulence are selected; they must be of the same population with clearly defined characteristics characteristic of it: shape, pigmentation, size, etc.
Inactivation of pathogen colonies is carried out in several ways:
- overheating, that is, the effect on the cultivated microorganism elevated temperature(56-60 degrees) a certain time (from 12 minutes to 2 hours);
- exposure to formalin for 28-30 days with maintenance temperature regime at a level of 40 degrees, a solution of beta-propiolactone, alcohol, acetone, or chloroform can also act as an inactivating chemical reagent.
Production of toxoids
In order to obtain a toxoid, 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, which are also used for “killed” vaccines: exposure to chemical reagents and overheating.
To reduce reactivity and susceptibility, antigens are purified from ballast, concentrated and adsorbed with aluminum oxide. The process of adsorption of antigens plays an important role, since the administered injection with a large 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.
Disposal 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 tools for an hour;
- disinfection in a solution of 3-5% chloramine for 60 minutes;
- treatment with 6% hydrogen peroxide also for 1 hour.
Expired medications must be sent to the district sanitary and epidemiological center for disposal.
