Measles vaccination status and evidence of immunity among medical students in Catalonia (Spain), 2023–2025: a cross-sectional study

BACKGROUND: Measles is a highly contagious infectious disease. The importance of vaccinating healthcare workers (HCW) and medical students as future HCW is underlined by the numerous measles outbreaks in health institutions. We aimed to assess the factors associated with complete vaccination, and measles serological status in relation to vaccination history among medical students in Catalonia (Spain). METHODS: A cross-sectional study was conducted among medical students attending four university teaching-units during the 2023-2024 and 2024-2025 academic years. Medical students completed a questionnaire and provided blood samples for measles IgG testing. Associations between positive serology, vaccination status, and independent variables (age, sex, country of birth, degree year, future speciality, vaccination attitudes, and measles vaccination history) were assessed using the odds ratio (OR) and 95% confidence interval (CI). RESULTS: Of the 255 participants, 79.2% were female, 92.5% were aged ≤ 24 years and 94.9% had received a complete schedule of two doses of measles vaccine. A complete vaccination schedule was associated with being a 5th-year student (aOR 5.26; 95% CI 1.43-20.48). Serological results were positive in 200 students (78.7%), and associated with none of the independent variables. Positive serology was observed in 79.3% and 58.3% of Spanish-born and non-Spanish-born students, respectively (aOR 0.38; 95%CI 0.12-1.27), but the difference was not statistically significant. CONCLUSIONS: A high proportion of medical students in our sample had received two doses of measles vaccine. In line with public health recommendations, medical students as future HCW should be required to provide documented proof of two doses of measles-containing vaccine prior to starting clinical training.