Currently, vaccination is one of the most actively used forms of prevention of various diseases. Vaccination is designed for a large number of diseases, the list of which continues to grow.
One of the most anticipated was the BCG vaccine. Its creation allowed at times to reduce the incidence and mortality from tuberculosis infection. Such a common infection in the eighteenth century was taken under vaccination control. However, even at present, tuberculosis cannot be attributed to vaccine-preventable diseases. First of all, this is due to the fact that the emerging immunity is temporary, especially in those cases when the body is exhausted by chronic diseases or in the case of congenital or acquired immunodeficiency.
In very rare cases, the development of a vaccine form of tuberculosis is possible, that is, tuberculosis is formed under the influence of a weakened strain microbe. The development of such a disease is also possible after several years after the introduction of the vaccine. The disease develops due to a weakening of the human immune system or as a result of general depletion of the body (anorexia).
BCG vaccination is carried out according to the following scheme: the first injection of the drug is on the fourth - 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 for a child at the age of seven, the second revaccination (at 14 years old) is carried out if there is a lack of immunity to the tuberculosis agent (that is, when the BCG vaccine has not been previously administered, and the person has not met with Koch’s bacillus environment).
In order to understand whether the child is infected with tuberculosis and needs revaccination or not, a Mantoux test is performed as an indicator of the body's reactivity 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 live and killed viral and microbial agents.
The composition of the BCG vaccine is represented by live mycobacterium tuberculosis of a special strain with reduced virulence. This strain was obtained by repeated cultivation in harsh conditions for the microbe. Immunity is formed as a result of the multiplication of an agent in the human body and the development of antibodies against this factor. A feature of the immunity that forms the BCG vaccine is that it is supported by the persistence of the microbe in the body. The same feature explains the possibility of developing post-vaccination tuberculosis.
The immunity received by a person as a result of vaccination is a natural vaccine. In addition, there is a natural non-vaccine immunity, the formation of which occurs as a result of the natural entry of Mycobacterium tuberculosis into the respiratory tract of a person. Such immunity is also very common, since there are a lot of possibilities for meeting the human body with Koch sticks . One of the most significant epidemiologically is the open form of tuberculosis, when, together with exhaled air, the patient secretes a microbial agent.
There are a number of contraindications for vaccine administration. 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. BCG vaccine is not administered to persons with persistent immunodeficiency, since the development of a generalized form of tuberculosis is possible - this is a constant contraindication for vaccination.