The outbreak of COVID-19 resulted in a decrease in tuberculosis notification rates globally. We compared tuberculosis incidence rates and disease severity in children seen in our centre prior and during COVID-19 pandemic.We performed a cohort study enrolling children aged under 18 years who received a diagnosis of tuberculosis (January 1st, 2010-December 31st, 2021) at our Pediatric Infectious Diseases Unit. Disease severity was evaluated based on: the classification proposed by Wiseman et al., smear positivity, presence of symptoms at presentation, lung cavitation, extrapulmonary disease, respiratory failure and need for intensive care support. Overall, 168 children (50.6% female, median age 69 months, IQR 95.4) received a diagnosis of tuberculosis, 156 (92.8%) between 2010–2019, before COVID-19 outbreak, and 12 (7.2%) between 2020–2021, during the pandemic. The annual tuberculosis notification rate dropped by 73% in 2021 (0.38/100000, 95%CI 0.1–0.96) compared with 2019 (1.46/100000, 95%CI 0.84–2.37). Compared to the pre-pandemic period, the proportion of children classified as severe was higher in 2020–2021 (5, 41.6% vs 23, 15.7%, p = 0.006) with a higher rate of respiratory failure (2, 16.7%, vs 4, 2.6%, p = 0.01) and an increased need for intensive care support (1, 8.3% vs 1, 0.6%, p = 0.01).Conclusion: During COVID-19 pandemic we observed a reduction in tuberculosis notification rate in pediatric population and a significant increase in disease severity. This scenario may be the consequence of a delay in diagnosis and an underreporting of cases, rather than the effect of a reduced transmission of tuberculosis. Children reached health-care services only in the need of urgent medical attention.What is Known:• COVID-19 pandemic had a huge impact on national health care systems, resulting in a reduction of access to medical care.What is New:• In Campania Region, Italy, a low tuberculosis incidence country, we witnessed a 75% reduction in tuberculosis notification rate during pandemic. In parallel we demonstrated a significant increase in disease severity, suggesting that the reduction in notification rate may be attributed to an underreporting of cases and consequential diagnostic delay, rather than a reduced transmission of infection.