Why is BCG vaccination necessary? A pediatrician talks about why you need to be vaccinated against tuberculosis and who should not be vaccinated.

BCG: what is it?

The BCG vaccine is used to prevent severe forms of tuberculosis.
It also protects against the most dangerous complications if a person does get sick. Tuberculosis is a common infectious disease (Fig. 1). In the world, up to 10 million people fall ill with it every year, and up to 1.4 million people. dies from this disease. In Russia, the incidence of tuberculosis has been declining in recent years. In 2021 it amounted to 41.2 people. per 100,000 population, and mortality is 5.2 people. per 100,000 population. Despite this, tuberculosis infection remains dangerous, and BCG vaccination is important to protect against it.

Figure 1. General information about tuberculosis. Source:

The BCG vaccine is live. It contains live vaccine strains. They are obtained using weakened bovine tuberculosis bacilli Mycobacterium bovis.

M. bovis is a mycobacterium of the tuberculosis complex that can cause tuberculosis in humans in the same way as the main causative agent of the disease, Koch bacillus (Mycobacterium tuberculosis). Bovine tuberculosis bacillus and Koch's bacillus have a number of similarities and differences. M. bovis produces a similar immune response and can be weakened in vitro. This allows the strain to be used for the production of a live attenuated vaccine.

Back in 1908, the development of BCG began in France. The vaccine was named after the first letters of the surnames of its creators, Albert Calmette and Camille Guérin: Bacillus Calmette-Guérin or BCG. It was tested in 1921, but the tests were unsuccessful. Later it was transferred to the USSR. Since the 1950s, the mass use of BCG for vaccination began in the USSR and other countries. New vaccines are currently being developed, but for now BCG remains the only means of immunoprophylaxis against tuberculosis.

In countries where the incidence of tuberculosis is high, WHO recommends that all healthy newborns be vaccinated in the first days of life. Russia is one of such countries. In regions where the incidence of tuberculosis is decreasing or is low, vaccination against tuberculosis is carried out selectively, only for risk groups.

BCG vaccination: what it protects against, at what age it is given

The vaccine got its name from the English abbreviation – BCG (Bacillus Calmette-Guerin). It includes a live attenuated strain of bovine tuberculosis bacillus. This bacterium is not dangerous to humans, but forms immune protection against severe forms of tuberculosis (damage to the bones of the spine, meningitis, severe damage to internal organs) and the transition of latent carriage of bacilli to an active form of infection (pulmonary tuberculosis). Source: D.T. Levi, N.V. Alexandrova Vaccinal prevention of tuberculosis // BIOpreparations. Prevention, diagnosis, treatment, 2015, p. 4-8

Today, this vaccination is given in the maternity hospital, on the 4th day of life of a full-term baby, if there are no contraindications. Premature babies are also vaccinated with BCG, but they must weigh more than 2500 g and have no health problems. Subsequently, BCG revaccination is carried out at the ages of 7 and 14 years according to the results of tuberculin tests (Mantoux).

In our country, BCG vaccination is included in the compulsory vaccination schedule of the national calendar - it is recommended for all children. But not all countries support the idea of ​​universal vaccination against tuberculosis at an early age. Some European countries and the United States have abandoned mass vaccination; they only vaccinate children at risk. This is explained by the low incidence of tuberculosis in these countries.

To whom and when do they do it?

The Russian national vaccination calendar recommends that all healthy newborn children be vaccinated against tuberculosis in the first days of life.

Further, Mantoux tests are performed annually to diagnose tuberculosis and detect infection with mycobacteria in children. This is a subcutaneous injection of tuberculin - a filtrate of killed cultures of Mycobacterium tuberculosis that have undergone special treatment. After the test, redness or a papule (solidification) may appear at the injection site. The reaction to tuberculin is assessed by its size (Fig. 2). If the test is negative (there is no severe redness or swelling at the injection site), then the child is healthy, and the doctor may recommend revaccination.

Figure 2. Assessment of response to tuberculin test. Source: MedPortal

Vaccination against tuberculosis can also be given to adults, but it is not as effective as in childhood. It is recommended to get vaccinated if a person is going to travel to a country with a high incidence of tuberculosis, or if he will have contact with patients. Vaccination is performed only if the tuberculin test gives a negative result.

Ruler-diagnostician

Against the backdrop of the total mass coverage of BCG, every year from the age of one to 15 years, children undergo an intradermal Mantoux test, the same tuberculin test that we mentioned a little earlier.

The reaction to a tuberculin test combines two immunodiagnostic responses (completely incompatible in essence!): a) immunity to tuberculosis is assessed - 5 millimeters, and b) simultaneously - possible infection with mycobacteria (or tuberculosis disease - we have everything the same!) - 6 millimeters. Note that the difference is 1 millimeter... And this difference is determined... with a student’s ruler, which in itself is absurd!

It is necessary to remind and clarify: in our country, EVERYONE WHO RECEIVED THE LIVE BCG VACCINE during the neonatal period is infected (which, by the way, does not mean “sick”) with mycobacteria. It follows that everyone who is susceptible to tuberculosis to one degree or another and who has a “memory” of a violent encounter with mycobacteria - BCG - should have a positive response “to infection”.

Practice has shown that the tuberculin test (Mantoux test) cannot serve as a diagnostic tool after BCG vaccination. To establish the actual percentage of the population infected, this diagnostic test should be used BEFORE BCG VACCINATION. And immunity to tuberculosis is determined by other tests outside the human body. Anti-tuberculosis immunity does not depend on the presence of antibodies; what is important here is the result of the functional state of immunocompetent cells. And the “student ruler” method in this case is an outright falsification of this PREVENTIVE... help.

In addition, it is common knowledge that vaccinating does not mean protecting. The vaccine may not work, but the vaccinated person is considered protected, which also refers to the area of ​​profanation. The result is important!

Experts from the WHO Ecology Committee, in contrast to the EPI Implementation Committee, having analyzed outbreaks of infectious diseases in different countries, came to the clear conclusion that infectious diseases recede (even without vaccinations!) with timely diagnosis, in the presence of high-quality water and a balanced diet. nutrition among the population, with the strictest EVERYDAY implementation of a set of anti-epidemic measures, which implies not only and not so much vaccinations... “The hope that an infectious disease can be defeated with the help of vaccines directed against this pathogen turned out to be too simplified, associated primarily with nature, properties and changing characteristics of pathogens,” WHO experts remind. In addition, other infectious diseases cannot be “defeated like smallpox,” each of which requires its own approach, its own program.

Carrying out BCG: according to the calendar and individually

In the absence of contraindications, healthy children are vaccinated according to the national calendar of preventive vaccinations twice:

• on days 3-7 of life before discharge from the hospital;
• at 6-7 years, if the tuberculin test is negative.

If there are contraindications, the vaccination is not given in the maternity hospital, but later, after discharge. In this case, a separate immunization schedule is drawn up for the child, planning it so that BCG is administered separately from all other vaccines. It is important to get vaccinated against tuberculosis as early as possible. If a child is weakened, underweight or has contraindications to the administration of the BCG vaccine, he is vaccinated with the BCG-M vaccine with a reduced content of live mycobacteria. This reduces the risk of complications.

Revaccination with BCG

This is a repeated vaccination in order to maintain the formed immunity.

Revaccination is carried out for healthy children, adolescents and adults at a certain age if they have negative results from all previous Mantoux tests. Revaccination with BCG should be carried out no earlier than three days after the Mantoux test and no later than two weeks.

For children vaccinated in the maternity hospital, the first revaccination is carried out when they reach 6-7 years of age (first grade students), the second revaccination is done at the age of 14-15 years (9th grade students).

Revaccination is not carried out:

• persons infected with tuberculosis or who have previously had tuberculosis;
• with a positive or questionable Mantoux test reaction;
• if complications arise from previous BCG vaccinations;
• during acute diseases, as well as during exacerbation of any chronic diseases;
• during exacerbation of allergic diseases;
• for malignant blood diseases and other neoplasms;
• in immunodeficiency conditions and during treatment with immunosuppressants.

Children who are temporarily exempt from vaccination are taken under observation and vaccinated after recovery and removal of all contraindications.

After the BCG vaccination and revaccination, other vaccinations can be done only after a month. During this time, immunity is formed after vaccination.

The reaction to BCG at the injection site during vaccination and revaccination varies. When revaccinating older children and adolescents, the reaction appears earlier than with vaccination, after 1-2 weeks.

Vaccinated children are monitored by local doctors together with clinic nurses. They check the reaction to the vaccine at the injection site 1, 3, 6, 12 months after vaccination and note the results in medical records.

Features of vaccination

It is important to carry out vaccination against tuberculosis as early as possible, in the first few days after birth. This will allow you to activate your immune system faster. If immunization is performed later, BCG vaccination cannot be combined with other vaccines. One month before and one month after vaccination against tuberculosis infection there should be no other vaccinations. An exception is vaccination against viral hepatitis B, which is performed in the maternity hospital on the first day of a child’s life.

When using the BCG vaccine, the correct technique for administering the drug is especially important. It is injected to a certain depth, strictly intradermally. Incorrect injection depth provokes local complications and reduces the effectiveness of vaccination. It is better if the vaccination is administered by medical staff in the maternity hospital. Nurses in maternity hospitals constantly carry out such vaccinations and do them correctly, and in addition, the child will remain under the constant supervision of doctors for some time after vaccination. No special preparation is needed for BCG vaccination.

Compatibility of BCG with other vaccinations

Simultaneous administration of other vaccines with the administration of BCG and BCG-M is not carried out. The interval between them should be one month. An exception is the vaccination against hepatitis B, which a newborn is given on the first day after birth, just 3 to 4 days before BCG. This regimen is used in many countries around the world and is safe, the frequency of possible adverse reactions to both vaccines does not increase, and the effectiveness, that is, the development of immunity, is maintained.

Contraindications for carrying out

Vaccination against tuberculosis cannot be done if the following contraindications exist:

• birth weight less than 2000 g;
• the presence of acute diseases (including intrauterine infection, severe damage to the nervous system, purulent-septic and other diseases);
• malignant neoplasms;
• primary immunodeficiency;
• use of immunosuppressants or radiation therapy (vaccination is performed 6 months or more after completion of therapy);
• generalized BCG infection in other children in the family;
• HIV infection in the child or his mother (if she did not take antiretroviral therapy).

Vaccination in these cases is carried out after removal of contraindications. The BCG-M vaccine can be used for it, for which the risk of complications is lower.

A little about the vaccine itself

The BCG vaccine is a mandatory vaccination in our country.
But it turns out that not all parents know what this vaccine is and why it is given. The vaccine against tuberculosis is called the BCG vaccine. It was obtained for the first time after numerous efforts in 1921 by scientists from France, microbiologist Calmette and his scientific partner, veterinarian Guerin. The BCG vaccine is made from live, but significantly weakened bovine tuberculosis bacillus. This vaccine meets all the requirements for vaccines.

It is harmless because the weakened bacterium has almost lost its ability to infect, but retains the ability to cause the formation of immunity against tuberculosis in the vaccinated body. However, despite the harmlessness of the vaccine, complications that occur after vaccination are rare (but still occur).

Many people wonder why the tuberculosis vaccine has such a strange name. It turns out that everything is very simple. BCG is the first letters of the French words Bacillus Calmette Guerin (Celmette-Guerin bacterium) reinterpreted into Russian.

What complications can occur after BCG vaccination?

Complications after this vaccination are divided into two categories:

1. Severe complications associated with generalization (spread) of infection. The BCG vaccine is, as noted above, a live culture. Therefore, it can cause specific (i.e., related to the development of the tuberculosis process) complications. As a rule, such complications are associated with improper selection of children for vaccination. However, I would like to emphasize that the risk of such complications is much less than the risk of the disease in an unvaccinated child.
2. Milder complications associated, among other things, with a violation of the vaccine administration technique or with a low-quality vaccine.

Among the main possible complications after BCG:

• Ulceration of the infiltrate. The area of ​​compaction or thickening of tissue at the injection site (infiltrate) increases in diameter (more than 1 mm) and ulcerates; The ulcer is painless, with little discharge.
• Formation of subcutaneous infiltrate. The infiltrate does not form in the skin, but under the skin. It looks like a “ball” that can be felt under smooth, unchanged skin. This complication is associated with an excessively deep injection of the vaccine, and if you do not consult a doctor in time, the infiltrate may break through and the infection will enter the bloodstream.
• Formation of a keloid (rough scar). This is a fairly rare complication, and it occurs less frequently in newborns than in older children. It is a common hereditary disease in which any damage to the skin is accompanied by excessive growth of scar tissue. If a keloid forms after vaccination, the scar becomes bright, blood vessels are visible through it, and sometimes itching appears.
• Spread of infection to lymph nodes. In this case, enlarged, painless axillary lymph nodes are identified, which mothers most often notice when bathing their child. Such a lymph node is the size of a hazelnut, and sometimes the size of a chicken egg. Occasionally, the infection breaks through the skin and a fistula is formed, that is, a channel through which pus drains.

If any of the above complications, as well as other unusual phenomena, occur, you should immediately consult a doctor.

Features of BCG vaccination

Before vaccination of newborns, the child’s condition is assessed taking into account all indicators on the Apgar scale. The drug is administered by a subcutaneous puncture in the area of ​​the superficial (deltoid) muscle of the left shoulder.

Over the course of 2-4 months, immunity to infection is formed in the child’s body. During this period, any other vaccination is contraindicated. It is advisable to protect your baby from the influence of colds.

The immune response to the vaccine manifests itself as a local reaction in the injection area after 1-2 months, in the form of:

1. slight swelling and redness;
2. change in skin color at the site of vaccination (even black);
3. the appearance of a purulent vesicle covered with a crust.

These signs should not cause concern, as they are a normal reaction of the body to the vaccine.

Healing of the wound at the vaccination site can take a long time (up to 4 months). Normally, the diameter of the scar formation after healing should not exceed 10 mm, and there should be no swelling or redness. A slight increase in temperature is possible.

Vaccination against tuberculosis: pros and cons

The BCG vaccine has been used for a long time, and it has a number of disadvantages, but so far it remains the most effective way to prevent tuberculosis.

At the same time, it is the effectiveness of immunoprophylaxis that causes the most controversy:

• The BCG vaccine does not prevent tuberculosis infection.
• If a person is already infected with Mycobacterium tuberculosis, the vaccine does not protect against the disease becoming active. According to WHO, a third of people worldwide are carriers of Mycobacterium tuberculosis.
• The immunity formed by the vaccine weakens over several years. Revaccination is not always effective, and because of this, adults are vulnerable to both primary infection and the transition of the latent form of tuberculosis to the active form.
• The BCG vaccine in children prevents up to 80% of severe forms of tuberculosis infection.
• Vaccination reduces the number of deaths associated with tuberculosis by 65%. The incidence of tuberculous meningitis is reduced by 64%, disseminated tuberculosis (with the formation of multiple lesions of lung tissue) - by 78%.
• Even if infected, those who have been vaccinated have a much milder course of the disease, with fewer complications.

The safety of the BCG vaccine is also controversial. Its use can indeed lead to a number of complications, but they occur very rarely. Local reactions associated with a violation of the drug administration technique are more common, but even these are not very common.