OBJECTIVE : High number of diphtheria cases has been recorded in East Java since 2011. Many efforts to tackle the problems did not produce good results. Outbreak response immunization (ORI) was the last action in order to reduce the incidence of diphtheria. The ORI was performed three times during 2018, covering all 38 districts in the province. The coverage of the ORI was more than 90% for each round. The objective of this study was to evaluate the impact of three rounds ORI against diphtheria in East Java Province.
METHODS : The surveillance data has been collected from all 38 district health offices on a daily, weekly, and monthly basis, from January until May 2019.. The data source were the community health centers, hospitals, medical officers, and the community. All data were pooled in the provincial health office. The analysis was done descriptively. Since 2008, all diphtheria cases were assessed by the diphtheria expert committee. If the committee decided to postpone the anti-diphtheria serum, the cases were considered as "not diphtheria".  
RESULTS : There were 754 cases in 2018 with 3 deaths. The average number per week for all suspected cases and those with ADS were 13.21 and 7.33, respectively. For the first 5 months in 2019, the average number of total diphtheria cases and those with ADS were 5.83 and 4.33, respectively. Most of the cases were below 19 years of age with incomplete immunization. Three districts did not record any cases in 2019.  One patients died in Kabupaten Pasuruan. Only 4 positive microbiological culture from the throat swab were recorded.  
CONCLUSION: The trend for the diphtheria cases in 2019 was better than in  2018. We need at least 12 months to decide the real impact of the ORI.