New cases of syphilis are clearly showing an increasing trend worldwide. However, in a sentinel surveillance system, the collection of information on disease outbreaks is limited, making it difficult to understand the overall outbreak situation and perform detailed analyses of patients' demographic characteristics and disease stages. In accordance with the revision of the Infectious Disease Prevention Act, syphilis was converted from a grade 4 infectious disease subject to sentinel surveillance to a grade 3 infectious disease subject to mandatory surveillance from January 1, 2024, with all medical institutions required to report syphilis diagnosis within 24 hours.