Live vaccine: description, species, efficacy and use

To create active immunity against some serious diseases helps vaccination. Currently, this method is recognized as the most effective, allowing to prevent the development of various severe pathologies of an infectious, bacterial and viral nature. Live vaccine contributes to the creation of long-term immunity. This special form of drugs for immunization has a number of advantages and disadvantages, with which everyone should be acquainted.

What are living vaccines?

To create live vaccines, weakened strains of pathogens that begin to multiply at the injection site. Such agents completely retain their immunogenic properties. Clinical presentation of the disease immunization with live vaccines does not cause (in most cases). Vaccine infection leads to the formation of a fairly persistent immunity: humoral, cellular and secretory.

To obtain weakened (attenuated) strains can be due to the inactivation of the gene, which is responsible for the virulence of the microorganism. The chemical and physical effects are used for inactivation. Many live vaccines are released 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 a persistent immunity, sometimes it is enough to enter the drug once.

A variety of live vaccines are divergent vaccines. At their manufacture microorganisms which are in close relationship to originators of infections, but not capable to cause disease are used. An example of such a vaccine is BCG, it is obtained from mycobacteria of bovine tuberculosis.

Benefits

Compared with inanimate vaccines, drugs with weakened strains of pathogenic bacteria have several advantages:

• The minimum dose of the drug.
• Fast development of immunity.
• Presence of various ways of introduction into an organism.
• Maximum natural immunogenicity.
• High efficiency (with proper application).
• Low cost.
• Absence of preservatives in the composition.
• Activation of all types of immunity.

Disadvantages of live vaccines

According to experts' reviews, weakened strains of pathogenic microorganisms used to create vaccines can cause the development of this disease (it happens extremely rarely). This is attributed to the patient's weakened immunity.

Live vaccine is very sensitive to temperature changes. Therefore, the negative reaction of the body is almost inevitable, if negligence was allowed regarding the proper storage or transportation of the drug. Also, the vaccine, damaged in this way, can completely lose its abilities and cause absolutely no reaction of the organism.

Doctors recommend avoiding the combination of live vaccine with other vaccine preparations. Otherwise, negative reactions of the organism may develop or the means will lose their effectiveness.

Live polio vaccine

A serious 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), able to protect humanity from this terrible disease.

The product is available in liquid form and is intended for oral administration. It has a bitter-salty taste, and therefore, when instilled, it is advisable to avoid getting the drug on the tongue. The drug should get on the tonsils (there are no taste buds), where the formation of permanent immunity begins. Vaccinated live vaccine is recommended after the application of inactivated.

According to reviews of immunologists, the vaccine contains all three types of poliomyelitis, which helps protect the body from all known variations of this ailment. Complications of the drug is extremely rare. However, many parents try to avoid vaccinating the child with this vaccine.

How does it work?

The Sabin vaccine (OPV), after ingestion, persists for a long time in the intestine and causes the formation of immunity similar to that which would develop after the disease. The first vaccination is carried out at the age of 6 months. Pre-babies inoculated inactivated vaccine twice - at 3 and 4.5 months. As a result, they must start producing antibodies capable of recognizing and protecting the body from a pathogenic pathogen. The live polio vaccine also stimulates the production of interferon, which also positively affects the state of the immune system.

Reviews

During the research it was found that OPV is much more effective than the inactivated vaccine. Doctors recommend compulsory passage of the full vaccination plan against poliomyelitis and a live, weakened vaccine must be used. At the same time, parents are not in a hurry to agree to use such a drug. This is associated with a risk of side effects: vaccine-associated poliomyelitis, fever, stool disorder, loss of sensitivity in the limbs, gait disturbance.

Of course, the use of live vaccines can provoke the appearance of a negative reaction of the body. However, such cases are extremely rare. Children who are born with immunodeficiency, congenital abnormalities of the gastrointestinal tract, or who have a weakened defense system, for example after suffering a serious illness, can suffer. In these cases, only inactivated vaccine is allowed.

How to protect yourself from measles?

Measles is a highly contagious infectious disease, which can be infected by any person, regardless of gender and age. In childhood, pathology is much easier to tolerate. A live measles vaccine will help to formulate immunity. A single-component vaccine is produced by a domestic manufacturer. The vaccine of Indian manufacture is also considered effective.

The product is released as a dry powder, which is diluted with a special solvent. A vaccinated vaccine can be stored for no more than an hour. Immunization with a monovalent vaccine allows you to avoid getting infected with an ailment or to transfer it in an easy form.

Planned primary vaccination is indicated at the age of 12-14 months. Re-enter the vaccine at 6 years old. There is the possibility of an individual vaccination schedule, which should be made by an immunologist.

Contraindications and complications

Frequent negative reactions of the body to the introduction of live measles vaccine are such symptoms as fever, skin rash, inflammation of the lymph nodes, cough. Experts say that this is a normal reaction of the body.

In children, such signs develop rarely. In general, the introduction of 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 a person is completely healthy. The vaccine is not allowed to be administered to women in the situation, persons with a history of tuberculosis and complications caused by previous vaccination.

Vaccination for rubella

Another child's disease, which is hard enough for adults, is rubella. The vaccine (live) is considered the most effective means of preventing infection. Particular danger pathology presents to pregnant women.

A 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 are already 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.