Vaccination helps to create active immunity against some serious diseases. Currently, this method is recognized as the most effective in preventing the development of various severe pathologies of an infectious, bacterial and viral nature. A live vaccine contributes to the creation of long-term immunity. This particular form of immunization preparation has a number of advantages and disadvantages that everyone should be aware of.
What are live vaccines?
To create live vaccines, weakened strains of pathogens are used, which begin to multiply at the injection site. Such agents fully retain their immunogenic properties. Immunization with live vaccines does not cause a clinical picture of the manifestation of the disease (in most cases). Vaccine infection leads to the formation of fairly stable immunity: humoral, cellular and secretory.
Weakened (attenuated) strains can be obtained by inactivating the gene responsible for the virulence of the microorganism. For inactivation, chemical and physical effects are used. Many live vaccines are available in dry form. This allows you to extend their shelf life. Dry live vaccines can be stored for more than 12 months at a certain temperature (2-8 °C). To create stable immunity, it is sometimes enough to inject the drug once.
A variety of live vaccines are divergent vaccines. In their manufacture, microorganisms are used that are closely related to infectious agents, but are not capable of causing disease. An example of such a vaccine is BCG, it is obtained from Mycobacterium bovine tuberculosis.
Benefits
Compared to non-live vaccines, preparations with attenuated strains of pathogenic bacteria have a number of advantages:
- Minimum doses of the drug.
- Fast development of immunity.
- Availability of different routes of administration.
- Maximum natural immunogenicity.
- High efficiency (when applied correctly).
- Low cost.
- No preservatives in the composition.
- Activation of all types of immunity.
Disadvantages of live vaccines
According to experts, attenuated strains of pathogens used to create vaccines can cause the development of a real disease (it happens very rarely). This is attributed to the patient's weakened immune system.
The live vaccine is very sensitive to temperature changes. Therefore, a negative reaction of the body is almost inevitable if negligence has been committed regarding the correct storage or transportation of the drug. Also, a vaccine spoiled in this way can completely lose its ability and cause absolutely no reaction of the body.
Doctors recommend avoiding combining live vaccines with other vaccines. Otherwise, negative reactions of the body may develop or the funds will lose their effectiveness.
Live polio vaccine
Severe infectious disease is poliomyelitis, which affects the brain and spinal cord. Pathology leads to damage to the nervous system and paralysis. In the middle of the last century, scientists developed a live vaccine (OPV) that could protect humanity from this terrible disease.
The product is available in liquid form and is intended for oral use. It has a bitter-s alty taste, and therefore, when instilled, it is recommended to avoid getting the drug on the tongue. The drug should get to the tonsils (there are no taste buds), where the formation of stable immunity begins. It is recommended to vaccinate with a live vaccine after using an inactivated one.
According to the reviews of immunologists, the vaccine contains all three types of polio, which helps protect the body from all known variations of this disease. The drug rarely causes complications. However, many parents try to avoid giving their child this vaccine.
How does it work?
The Sabin vaccine (OPV) after being ingested remains in the intestine for a long time and causes the formation of immunity, similar to that which would develop after an illness. The first vaccination is carried out at the age of 6 months. Previously, babies are vaccinated with an inactivated vaccine twice - at 3 and 4.5 months. As a result, they should begin to produce antibodies that can recognize and protect the body from a pathogenic agent. The live polio vaccine also stimulates the production of interferon, which also has a positive effect on the immune system.
Reviews
In the process of research, it was found that OPV is significantly more effective than an inactivated vaccine. Doctors recommend mandatory completion of the full polio vaccination schedule and mandatory use of a live attenuated vaccine. At the same time, parents are in no hurry to agree to the use of such a drug. This is associated with the risk of developing side effects: vaccine-associated poliomyelitis, fever, stool disorder, loss of sensation in the limbs, gait disturbance.
Of course, the use of live vaccines can provoke a negative reaction of the body. However, such cases are extremely rare. Children born with immunodeficiency, congenital pathologies of the gastrointestinal tract, or having a weakened defense system, for example, after sufferingsevere illness. In these cases, only inactivated vaccine is allowed.
How to protect yourself from measles?
Measles is a highly contagious infectious disease that can affect anyone, regardless of gender or age. In childhood, pathology is much easier to tolerate. The live measles vaccine will help build immunity. A single-component vaccine is produced by a domestic manufacturer. An Indian-made vaccine is also considered effective.
The product is produced in the form of a dry powder, which is diluted with a special solvent. The finished vaccine can be stored for no more than an hour. Immunization with a monovalent vaccine allows you to avoid contracting the disease or to transfer it in a mild form.
Routine primary vaccination indicated at 12-14 months of age. The vaccine must be re-introduced at 6 years of age. There is the possibility of an individual vaccination schedule, which should be compiled by an immunologist.
Contraindications and complications
Frequent negative reactions of the body to the introduction of a live measles vaccine are symptoms such as fever, skin rashes, inflammation of the lymph nodes, cough. Experts assure that this is a completely normal reaction of the body.
Children rarely develop these symptoms. In general, the administration of the live measles vaccine is well tolerated. Before vaccination, it is necessary that the doctor examine the child (adult patient) and exclude the presence of contraindications (permanent and temporary). It is important that the person is completely he althy. The vaccine must not be administered to women in position, to persons with a history of tuberculosis and complications caused by previous vaccination.
Vaccination against rubella
Another childhood illness that is quite difficult for adults to endure is rubella. The vaccine (live) is considered the most effective means of preventing infection. Pathology is especially dangerous for pregnant women.
The live vaccine (one-component) is produced by Croatian, French and Indian specialists. According to reviews, side effects often develop in adults who have been vaccinated with a weakened vaccine. A slight increase in lymph nodes, general weakness, fever, skin rashes disappear on the second day.
Persons prone to severe allergic reactions are recommended to be under the supervision of specialists after the administration of the drug.
