Children who recover from COVID-19 remain at risk of developing tuberculosis

The global recognition of the Russian test speaks, among other things, about the quality of diagnosis and treatment of tuberculosis in our country. What is the situation with childhood tuberculosis, "RG" was told by the chief freelance pediatric TB specialist of the Ministry of Health of Russia, head of the department of tuberculosis in children and adolescents of the National Medical Research Center for Phthisiopulmonology and Infectious Diseases, Professor Valentina Aksenova.

Valentina Alexandrovna, our anti-covid vaccine, which was used in many countries, nevertheless, has not received official recognition from WHO. What does the fact that the Russian test is included in the WHO recommendations indicate?

Valentina Aksenova: Our "Diaskintest" is an innovative skin test that helps to detect infection with Mycobacterium tuberculosis. Moreover, it is important to identify patients with a high risk of developing an active tuberculosis process. A big plus of our test is the absence of false positive results. This means we can detect active tuberculosis at an early stage. In our country, by the way, this test has been used for a long time, since 2008, and in 2017 it was included as mandatory in the order of the Russian Ministry of Health during preventive examinations. Of course, the accuracy and timeliness of diagnosis is the key to an effective fight against this dangerous infection.

It is known that serious progress has been made in adult tuberculosis in Russia - the incidence is decreasing every year. What is the situation with children?

Valentina Aksenova: In the world, more than a million children fall ill with tuberculosis every year, about 233,000 die. As a rule, these are children under the age of five. In our country, the situation is completely different: prevention has become a priority, and in the last 10-15 years, the incidence of tuberculosis in children has been decreasing every year. Since 2017, among children from birth to 14 years old, it has decreased by more than a third - by 35.4 percent (from 9.6 to 6.2 per 100 thousand children), among adolescents - by 40.6 percent (from 21. 2 to 12.6 per 100 thousand). There are practically no severe forms of tuberculosis in Russia.

But still: where do children get sick? Who is at risk?

Valentina Aksenova: No prevention will help to avoid infection if a sick adult is next to the child. Therefore, in the risk group, first of all, children in contact with an adult with tuberculosis. The most important rule for the prevention of tuberculosis in children is the isolation of the child from the carrier of the disease. Even if it's his parents.

Treatment of an adult should take place away from the child until the phase of active isolation of bacteria is completed. If parents refuse hospitalization (unfortunately, this happens), then it is necessary to isolate the child from the family. For this, there are anti-tuberculosis sanatoriums.

Also at risk for the development of tuberculosis are children with reduced immunity, with chronic diseases, diabetes mellitus and autoimmune pathology, especially if the child receives drugs that can lead to a decrease in immunity for a long time. Few people know about it, but people with diabetes are 4-5 times more likely to get TB.

And in young children, infections such as herpes, cytomegalovirus, neurological diseases most often become risk factors. And finally, a special risk group for tuberculosis is children who have not been vaccinated with BCG. A new coronavirus infection is one of the provocateurs of a "sleeping" tuberculosis infection.

How to protect yourself from infection?

Valentina Aksenova: Rather, not from infection, but from the development of the disease. It is important to identify the disease as early as possible, for this it is necessary to undergo preventive examinations in a timely manner. Today, we have the widest range of diagnostic tools in the world for this, from skin tests, which are applicable in children and adolescents, to the possibility of conducting x-ray studies - fluorography and computed tomography - in adults. In addition, laboratory tests for tuberculosis are available for people of all ages, which are carried out on the basis of a blood test.

It is important that modern immunological tests make it possible to detect the presence of a latent (latent) phase of the course of the disease, in which it is possible to carry out prophylaxis and prevent the development of an active disease, which is very dangerous not only for the person himself, but also for his environment. Such samples include a test with a recombinant tuberculosis allergen (the same test that has just been recognized by WHO). In addition, we have at our disposal laboratory tests for the determination in the blood of cells that produce gamma-interferon in response to the presence of Mycobacterium tuberculosis in the human body (Elispot method).

BCG vaccination is given to babies in the maternity hospital. In connection with anti-vaccination sentiments, are there many refusals and how does this affect the health of children of "refuseniks" and collective immunity?

Valentina Aksenova: According to the National Immunization Schedule, 95 percent of children receive their first tuberculosis vaccine.

But those who have medical contraindications are vaccinated later. Parents may refuse to be vaccinated, but by doing so they deprive the child of the chance to avoid a severe form of the disease in case of infection.

The fear of vaccinations is caused by the fear of complications, although in fact such cases are rare. At the same time, parents' refusal to vaccinate can lead to an increase in the incidence among children, the appearance of severe forms of the disease, which can end very sadly. It is also dangerous that parents refuse immunological tests. Mycobacterium tuberculosis, once entering the body, has the ability to stay there for a long time in a "sleeping" state. As long as the child has good immunity, the pathogen does not manifest itself in any way, the infected child feels great. But in any stressful situations (going to school, heavy physical exertion, etc.) or diseases that lead to a decrease in immunity, mycobacterium begins to multiply actively - an active form of the disease develops. A coronavirus infection can also act as such a trigger. By refusing immunological skin tests, parents run the risk of missing a latent form of tuberculosis in a child. And the risk that under adverse conditions it will become active is one in ten.

Most children get vaccinated, but why does the incidence still persist?

Valentina Aksenova: The BCG vaccine does not protect against primary infection, but protects against the development of severe forms of tuberculosis: for example, tuberculous meningitis, bone tuberculosis, which, even with successful treatment, can end in disability. In Europe, this practice has been abandoned. There, only at-risk infants who, after birth, will be next to a TB patient, receive the vaccine. But even the exclusion of Russia from the list of countries with a high burden of tuberculosis does not allow canceling vaccination in our country. The risk of severe forms of tuberculosis is too great. Those parents who refuse to vaccinate make a big mistake - they risk the health of their children.

Fortunately, most of them are vaccinated, and precisely because vaccination and screening are well established in our country, the incidence of children is decreasing every year. This year, about 2,000 children fell ill, but there are practically no severe forms.

Parents are often afraid of complications because the vaccine is "live". Is it possible to avoid complications (albeit extremely rare), and are there prospects for the development of more modern "non-live" vaccines?

Valentina Aksenova: The "live" BCG vaccine is used not only in our country, but all over the world - this vaccine has been around for more than 100 years. Work on the creation of a new vaccine against tuberculosis is being actively carried out, including by our scientists. A booster, that is, a vaccine that enhances the action of BCG, has been developed, but clinical studies have not yet been completed on it. So at the moment, BCG remains the only vaccine that has proven effective in preventing the development of severe generalized forms of tuberculosis.

As for possible complications, back in 1997, a federal center for monitoring complications after BCG was created in Russia, as well as a register in which each such case is entered. Long-term monitoring and analysis showed that complications can occur if the technique of drug administration is violated. Therefore, together with Rospotrebnadzor, compulsory training of nurses has been introduced - and they update their knowledge every two years.

Each case of complications is analyzed, and, as a rule, they are associated with the immune system of the child himself - some kind of immunodeficiency. At present, a method for assessing immunity in children has been developed in Russia, which allows diagnosing disorders of the immune system, detecting the presence of primary and secondary immune deficiency. Starting next year, this method will be used to screen all newborns in the country.

How has the pandemic affected the TB situation?

Valentina Aksenova:The possibilities for prevention and the availability of TB treatment during the pandemic have decreased, the coverage of children with immunodiagnostics has decreased in 2020. But already in 2021, the pace of preventive measures was restored, and at the end of last year, the incidence of children remained at the same level. However, do not forget that children who have had a coronavirus infection need closer attention from doctors regarding an increased risk of developing tuberculosis. Coronavirus infection mainly affects the lungs and severely affects the immune system - which means, as I already mentioned, the risk of a latent infection becoming active increases. Therefore, children who have had a coronavirus infection must definitely undergo immunodiagnosis twice a year with modern immunological tests - and this applies to a child of any age.