Vaccination Among Patients Undergoing Treatment with Janus Kinase Inhibitors: Coverage and Associated Factors

Background and Objectives: Patients treated with Janus kinase inhibitors (JAKi) are at increased risk of infections that can be prevented through vaccination. This study evaluated vaccination coverage and associated factors among such patients. Materials and Methods: A cross-sectional study was carried out in the Zaragoza III Healthcare Sector. People receiving JAKi treatment in 2024 were selected. Variables were obtained by reviewing records. Associations with pneumococcal, shingles, 2024–2025 influenza and COVID-19 vaccination were analyzed using bivariate analysis and multiple logistic regression models. Results: A total of 347 patients were analyzed; 64.8% were women with a mean age of 50.8 years. For the 2024–2025 season, influenza vaccination coverage was 51.3%, and COVID-19 vaccination rate was 33.7%. Vaccination coverage against pneumococcal disease and shingles was 76.7% and 73.8%, respectively. Variables associated with having received the four vaccines were being 60 years of age or older (aOR: 2.74; 95% CI: 1.42–5.31), having received the influenza vaccine (aOR: 6.7; 95% CI: 2.85–15.63) and the COVID-19 vaccine (aOR: 4.4; 95% CI: 2.19–8.88) in the previous season, and having been seen at the Preventive Medicine Department Vaccination Clinic (aOR: 9.60; 95% CI: 2.96–31.18). Conclusions: Vaccination rates vary by vaccine, with coverage for influenza and COVID-19 leaving significant room for improvement. Understanding vaccination rates and their associated factors enables the design of specific strategies to improve vaccination coverage. In these strategies, the Preventive Medicine Department Vaccination Clinics can play an important role.