[Surveillance and public health at the borders: an analysis of immediate reporting events in Paraná State, Brazil (2010-2019)].

International borders pose health risks due to the intense movement of people and products, requiring surveillance and specific public health interventions. In Brazil, territorial diversity accentuates these challenges. The aim of the present study was to analyze the pattern of the mandatory immediate reporting of public health events in border regions of Brazil and more specifically in the state of Paraná from 2010 to 2019. Fourteen events from the National List of Compulsory Notification of Diseases that require immediate reporting to the three levels of government were analyzed using data from the Brazilian Health Information and Informatics Department. For each event, incidence rates were compared between border and non-border municipalities on two levels (nationally and in the state of Paraná). Absolute and relative frequencies as well as incidence and mortality rates (per 100,000 inhabitants) were calculated. Rate ratios (RR) were calculated to compare excess risk between groups. A total of 50,628 public health events occurred in the period studied; the most frequent were cases of measles (66.44%) and deaths related to dengue (11.52%). Cases of extra-Amazonian malaria (RR = 32.41), botulism (RR = 6.94), hantavirus (RR = 2.49), and deaths related to dengue (RR = 1.39) were concentrated at the borders. The incidence of measles was lower in border regions. The dynamics of extra-Amazonian malaria, dengue, hantavirus, and botulism at borders differed from those in the rest of the country. The high incidence at borders reveals critical vulnerabilities that require urgent, coordinated action. It is essential to strengthen surveillance and promote shared intersectoral strategies to address the unique challenges of these areas. Strengthening strategic units, such as the Strategic Information Center for Health Surveillance, improves surveillance and integration and ensures rapid responses.