Vaccines (definition, the classification of which is discussed in this article) are immunological agents used as active immunoprophylaxis (in other words, to form an active persistent immunity of the body to this particular pathogen). According to the WHO, vaccination is the best way to prevent infectious diseases. Due to the high efficiency, simplicity of the method, the possibility of a wide coverage of the vaccinated population for mass prevention of pathologies, immunoprophylaxis in many countries is classified as a state priority.
Vaccination
Vaccination is a special preventive measure aimed at protecting a child or an adult from certain pathologies completely or significantly reducing their occurrence when they occur.
Similar effect is achieved by "learning" immunity. With the introduction of the drug, the body (more precisely, its immune system) fights the artificially introduced infection and "remembers" it. With repeated infection, immunity is activated much faster and completely destroys foreign agents.
List of ongoing vaccination activitiesincludes:
- selection of persons to be vaccinated;
- drug choice;
- formation of the scheme for the use of the vaccine;
- efficiency control;
- treatment (if necessary) of possible complications and pathological reactions.
Vaccination methods
- Intradermal. An example is BCG. The introduction of a live vaccine is carried out in the shoulder (its outer third). A similar method is also used to prevent tularemia, plague, brucellosis, anthrax, Q fever.
- Oral. It is used to prevent poliomyelitis and rabies. Oral treatments for influenza, measles, typhoid fever, meningococcal disease in development.
- Subcutaneous. With this method, a non-sorbed drug is injected into the subscapular or shoulder (outer surface at the border of the middle and upper thirds of the shoulder) area. Advantages: low allergenicity, ease of administration, resistance of immunity (both local and general).
- Aerosol. It is used as an emergency immunization. Highly effective are aerosol agents against brucellosis, influenza, tularemia, diphtheria, anthrax, whooping cough, plague, rubella, gas gangrene, tuberculosis, tetanus, typhoid fever, botulism, dysentery, mumps B.
- Intramuscular. Produced in the muscles of the thigh (in the upper anterolateral part of the quadriceps femoris). For example, DPT.
Modern classification of vaccines
There are several vaccine divisionsdrugs.
1. Product classification by generation:
- 1 generation (corpuscular vaccines). In turn, they are divided into attenuated (weakened live) and inactivated (killed) agents;
- 2 generation: subunit (chemical) and neutralized exotoxins (anatoxins);
- 3rd generation represented by recombinant hepatitis B and recombinant rabies vaccines;
- 4th generation (not yet commercialized), represented by plasmid DNA, synthetic peptides, plant vaccines, vaccines containing 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 living but weakened microorganisms;
- killed, created on the basis of microorganisms inactivated in various ways;
- vaccines of chemical origin (based on highly purified antigens);
- vaccines that are created using biotechnological techniques, in turn are divided into:
- synthetic vaccines based on oligosaccharides and oligopeptides;
- DNA vaccines;
- genetically engineered vaccines created on the basis of products resulting from the synthesis of recombinant systems.
3. In accordance with the antigens that are part of the preparations, there is the following classification of vaccines (that is, they may be present as antigens in vaccines):
- whole microbial cells (inactivated or live);
- individual components of microbial bodies (often protective Ag);
- microbial toxins;
- synthetic-generated Ag microbes;
- Ag, which are obtained using genetic engineering techniques.
Depending on the ability to develop insensitivity to several or one agent:
- monovaccine;
- watering vaccines.
Classification of vaccines according to Ag set:
- component;
- corpuscular.
Live vaccines
For the manufacture of such vaccines, weakened strains of infectious agents are used. Such vaccines have immunogenic properties, however, the onset of symptoms of the disease during immunization, as a rule, does not cause.
As a result of the penetration of a live vaccine into the body, stable cellular, secretory, humoral immunity is formed.
Pros and cons
The benefits of a live vaccine (classification, application discussed in this article):
- minimum dosage required;
- the possibility of a variety of ways of vaccination;
- quick development of immunity;
- high efficiency;
- low price;
- immunogenicity as natural as possible;
- contains no preservatives;
- under the influence of such vaccines, all types of immunity are activated.
Negatives:
- if the patient has a weakenedimmunity with the introduction of a live vaccine, the development of the disease is possible;
- vaccines of this type are extremely sensitive to temperature changes, 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.
Classification of live vaccines
The following types of live vaccines are distinguished:
- Attenuated (weakened) 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 responses. Among such vaccines, the best known are drugs for the prevention of typhoid fever, anthrax, Q fever and brucellosis. But still, the main part of live vaccines is antiviral drugs for adenovirus infections, yellow fever, mumps, the Sabin vaccine (against polio), rubella, measles, influenza;
- Divergent vaccines. They are made on the basis of related pathogens of infectious pathologies strains. Their antigens provoke an immune response that is cross-directed to the antigens of the pathogen. An example of such vaccines is the smallpox vaccine, which is based on the vaccinia virus and BCG, based on mycobacteria that cause bovine tuberculosis.
Influenza Vaccines
Vaccines are the most effective way to prevent influenza. They are biologics that provide short-term resistance to influenza viruses.
Indications for such vaccination are:
- age 60 and over;
- chronic bronchopulmonary or cardiovascular pathologies;
- pregnancy (2-3 trimesters);
- outpatient and inpatient staff;
- persons permanently staying in closed communities (prisons, hostels, nursing homes, etc.);
- inpatients or outpatients with hemoglobinopathies, immunosuppression, liver, kidney and metabolic disorders.
Varieties
The classification of influenza vaccines includes the following groups:
- Vaccines live;
- 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);
