Several diphtheria outbreaks have occurred in the province of East Java, Indonesia since 2011. A three-round outbreak response immunisation (ORI), in 2018 was the final effort to stop an outbreak in the province. The purpose of this study was to assess the impact of the ORI 2018 in the province of East Java – six months after the programme was completed. Monitoring data have been collected from January to June 2019. Data sources included distributors, hospitals, health facilities in the community and private and paramedics. The data comprised demographics, medical facilities, immunisation history of the patient, clinical signs and symptoms, some laboratory test results and further testing. 

Over the six month period, the Diphtheria Expert Committee agreed to 97 cases of diphtheria. There were reports from 36 out of 38 districts. One patient died, which indicated a % fatality rate. The majority were 19 years old or younger and were immunised completely. There were 24% of patients above 19 years. The number of cases recorded decreased significantly in 2019 compared to 2017 and 2018. Only four positive results have been obtained. The subtype Mitis was present in two cases, with Gravis in the other two. In the first six month of 2019 Diphtheria ORI in East Java had a major impact.