An Overlooked Risk Group in Adult Immunization: Vaccination Awareness and Knowledge in Patients with Cushing's Syndrome: A Cross-sectional Study.

Objective: The aim was to quantify registry-documented adult vaccine uptake among patients with Cushing's syndrome and to assess vaccine awareness in a voluntary survey subgroup. Materials and Methods: We conducted a record-based, retrospective, cross-sectional analysis of adults with confirmed Cushing's syndrome who were followed at a tertiary endocrinology clinic in Türkiye between January 1, 2017, and May 31, 2023. Vaccine histories were obtained from the national vaccination registry. In addition, a structured telephone questionnaire assessed awareness of vaccines for hepatitis A-D, pneumococcal disease, herpes zoster, influenza, and COVID-19 in a convenience sample of reachable, consenting patients. Analyses were descriptive; subgroup comparisons were exploratory. Results: The registry cohort included 119 patients (83.2% female; median age 51 years).Beyond SARS-CoV-2 vaccination, uptake of routinely indicated adult vaccines was low: tetanus-diphtheria vaccine (38.7%), pneumococcal conjugate vaccine (23.5%), hepatitis B vaccine (18.5%), influenza vaccine (2.5%), and meningococcal vaccine (1.7%). In the survey subgroup (n=35), awareness of hepatitis B infection was high (80.0%), but knowledge of hepatitis A (28.6%) and hepatitis B (51.4%)vaccines was limited. Although 80.0% reported awareness of pneumococcal vaccination, only 20.0% reported having received it; the most common reason cited was that it was perceived as unnecessary. Conclusion: Adults with Cushing's syndrome had high SARS-CoV-2 vaccine uptake but substantial gaps in uptake and awareness of other recommended vaccines. Routine immunization assessment and proactive counseling in endocrinology clinics may help close preventable vaccination gaps.