Rising syphilis incidence and delayed neurological risk in the context of outcome oriented surveillance

Abstract Syphilis has re-emerged as a sustained global public health concern, with surveillance systems across North America, Europe, and parts of Asia documenting consistent increases in reported infectious cases over the past decade. Although neurosyphilis remains uncommon, absolute case numbers have risen modestly in parallel with expanding infection bases in several high-income settings. Current evidence does not support neurosyphilis as a population-level neurological epidemic; rather, observed increases appear proportionate to overall incidence trends. Interpretation of these patterns is shaped by structural factors. Surveillance systems remain largely testing-dependent, and reported cases may not fully capture the true burden of infection. In addition, incomplete post-treatment follow-up, variability in diagnostic practices, and delays in healthcare-seeking behavior related to stigma may influence case detection and reporting. Neurosyphilis may also emerge years after initial infection and present with heterogeneous neurological manifestations, including stroke-like syndromes and cognitive impairment, which complicate timely recognition. These structural limitations highlight the need for a broader surveillance perspective that extends beyond incident infections to include delayed clinical outcomes. This Perspective proposes a conceptual shift from incident-focused surveillance toward outcome-oriented surveillance incorporating longitudinal treatment follow-up, reinfection tracking, and integration of neurological outcome data within existing public health systems. Such an approach may improve detection of delayed complications while maintaining proportional interpretation of epidemiological trends. From a public health perspective, proportionate risk governance is essential. Strengthening testing accessibility, ensuring adequate serologic follow-up, and promoting context-sensitive diagnostic vigilance may reduce preventable neurological sequelae while maintaining balanced risk interpretation.