Doctolib needed a dedicated Vaccination Module to help doctors and clinics run flu and COVID campaigns efficiently, but also to finally modernize the way vaccinations are tracked, accessed, and shared across practitioners. Before this project, practices relied on generic appointment types and manual work: opening time slots, verifying eligibility, planning second doses, and checking stock. At the same time, patients often couldn’t find their old paper vaccination booklet, forgot their past doses, or had incomplete medical history when visiting a new practitioner. This created operational inefficiencies for practices and serious gaps in patient follow-up. I led the design of a complete 0 → 1 Vaccination Module that: • Helps practices create structured vaccination campaigns quickly • Automates key operational tasks • Provides patients with a digital vaccination booklet stored inside Doctolib • Allows any practitioner to instantly access validated vaccination history This module didn’t just reduce admin work, it improved continuity of care, made vaccination status clear for everyone, and helped ensure patients stay up-to-date with mandatory or recommended vaccines in France.