Multicenter Italian Observational Cohort Study on Tuberculosis in Pediatric Age

In recent decades, Tuberculosis (TB) has been considered, in industrialized countries, as predominantly an infectious disease of the elderly. However, since the 2000s, TB has re-emerged not only in the elderly but also in the young and especially in pediatric populations. Among the factors influencing the increase in the incidence of this pathology are certainly to be considered the rise in immigration from countries with high endemicity, where TB still represents a significant cause of morbidity and mortality, the spread of immunodeficiency caused by HIV infection, the use of immunosuppressive drugs, and the emergence of strains of M. tuberculosis resistant to traditional antibiotic therapy.

According to the WHO report of 2021, approximately 10 million new cases were reported in 2020, of which 1 million occurred in the pediatric population. However, epidemiological data available on TB in pediatric age are extremely limited due to diagnostic difficulties in this patient category. In children, in fact, bacteriological examination is negative in 95% of cases, and the diagnosis is made through a combination of clinical criteria and tests that are poorly specific for tuberculous infection and especially not universally accepted. In addition to diagnostic controversies, children are almost never included in national surveillance systems due to the lack of connections between individual pediatricians, pediatric hospitals, and national surveillance programs. It is therefore reasonable to assume that this condition may be significantly underestimated both in Italy and worldwide.

Another important aspect to consider is that tuberculous disease, whether active or latent, in a child should be considered a sentinel event that indicates recent transmission of M. tuberculosis within the community. Especially in the pediatric population, in addition to the mandatory reporting of confirmed cases of TB disease, it is important to identify cases of latent TB through historical and diagnostic criteria. Children indeed have a greater likelihood that the disease will progress to the active form compared to adults and that the progression will be towards a more severe form. Children with latent tuberculous infection also become a reservoir for the transmission of the infection, fueling future epidemics.