BCG vaccine

Currently, vaccination is one of the most actively used forms of prevention of various diseases. Vaccine prophylaxis is designed for a large number of diseases, the list of which continues to grow.

One of the most long-awaited was the BCG vaccine. Her creation allowed to reduce morbidity and mortality from tuberculosis infection several times. Such an infection, common in the eighteenth century, was taken under the control of vaccination. However, even now, tuberculosis can not be attributed to vaccine-preventable diseases. First of all, this is due to the fact that the emerging immunity is temporary, especially in cases when the body is exhausted by chronic diseases or in case of congenital or acquired immunodeficiency.

In very rare cases, the development of a vaccinal form of tuberculosis is possible, that is, tuberculosis is formed under the influence of a microbe of an attenuated strain. The development of such a disease is possible even after a few years after the introduction of the vaccine. The disease develops because of the weakening of the human immune system or as a result of general body exhaustion (anorexia).

BCG vaccination is carried out according to the following scheme: the first administration of the drug - on the fourth - the sixth day from the birth of the child. This manipulation, as a rule, is carried out directly in the maternity hospital. The first revaccination is carried out by a child at the age of seven years, the second revaccination (at 14 years) is carried out if there is a lack of immunity to the tuberculosis agent (that is, when the BCG vaccine was not introduced before, and the person did not meet with Koch's stick environment).

In order to understand whether a child is infected with tuberculosis and if he needs a revaccination or not, they conduct a Mantoux test, as an indicator of the reactivity of the organism with respect to the tuberculosis agent. Distinguish between normal and hyperergic reactions, depending on the size of the formed papule and its severity.

The composition of various vaccines can include both living and killed viral and microbial agents.

The composition of the BCG vaccine is represented by living mycobacteria of a tuberculosis of a special strain with reduced virulence. This strain was obtained by repeated cultivation under severe microbial conditions. Immunity is formed as a result of the propagation of the agent in the human body and the production of antibodies against this factor. The peculiarity of the immunity, which forms the BCG vaccine, is that it is maintained by the persistence of the microbe in the body. This same feature explains the possibility of developing post-vaccination tuberculosis.

Immunity received by a person as a result of vaccination is a natural vaccine. In addition, there is a natural non-vaccinal immunity, the formation of which occurs as a result of the natural entry of mycobacterium tuberculosis into the human respiratory tract. This immunity is also very common, since the possibilities of meeting the human body with Koch's rods are huge. One of the most significant epidemically is the open form of tuberculosis, when together with the exhaled air the patient releases a microbial agent.

There are a number of contraindications for the introduction of the vaccine. All of them are divided into temporary (lead to a delay in vaccination) and permanent (in this case, vaccination is not carried out). Temporary contraindications for vaccination include prematurity (the weight of the newborn is less than 2.5 kilograms), as well as a number of acute diseases and exacerbations of chronic pathologies. The BCG vaccine is not administered to people with persistent immunodeficiency, since it is possible to develop a generalized form of tuberculosis - this is a constant contraindication for vaccination.