Healthcare workers (HCWs) are at high risk of COVID-19 infection despite vaccination. Limited data exist on COVID-19 cases among vaccinated HCWs. This study aimed to describe the clinical characteristics and outcomes of RT PCR-confirmed COVID-19 cases in vaccinated HCWs, at a COVID clinic in a medical college hospital. This single-center, prospective cohort study included HCWs who received at least one dose of the COVID-19 vaccine and tested positive for COVID-19 within 6 months. Data on demographics, symptoms, work category, COVID-19 vaccination interval, and infection severity were collected. Of 2381 vaccinated HCWs, 105 tested positive and were categorized as mild, moderate, or severe cases. Among vaccinated HCWs, 4.41% had post-vaccine COVID-19 infections. All 105 cases received the first dose, and 79 received the second dose. Of the cases, 47.6% were partially vaccinated, and 53.3% were breakthrough cases. The mean age was 30.90±8.69 years, with 63.8% male and 36.2% female cases. Most cases (85.7%) acquired infection in the hospital, and 47.6% had direct contact with COVID-19 patients. Common symptoms included fatigue (85.7%), fever (82.9%), and cough (64.8%). Among cases, 93.3% were mild, 5.7% were moderate, and 0.9% were severe. Hospital admission and supplemental oxygen therapy were required for moderate and severe cases. No mortality was reported. Certain variables were associated with age, preventive measures, workplace type, symptoms, and comorbidities. Breakthrough infections can occur among fully vaccinated HCWs but with reduced severity and mortality. Monitoring and infection control measures remain crucial even in vaccinated individuals. This study provides insights into clinical presentations, oxygen therapy requirements, and outcomes of post-vaccine COVID-19 cases among HCWs. The data will inform strategies for booster doses to prevent COVID-19.