Abstract: Objective: To analyze and evaluate the long-term epidemiological effect of the hemorrhagic fever with renal syndrome (HFRS) vaccine in a large scale population in Junan county, Shandong province, from 1995 to 2005. Methods: The experimental epidemiological method was used to establish two groups (the vaccination group and the control group) and contrast the experimental epidemiological indexes, such as the incidence density, the protective rate and the index of effectiveness between the two groups; The cumulative incidence density was calculated and the morbidity level and the protective effect of HFRS vaccine were compared between the two groups at different vaccination times. Results: The incidence density of the vaccination group was significantly lower than that of the control group (χ²=79.9210，P＜0.05), the total protective rate was 92.61%（95% CI：87.09～98.13）and the effectiveness index was 13.54（95% CI: 6.41～28.57）; Based on the vaccination time, the protective rate in the 1st to 11th year was respectively 100.00%, 95.56%, 92.18%, 92.09%, 91.45%, 92.05%, 92.47%, 92.52%, 92.56%, 92.59%, and 92.61%. Conclusion: Using HFRS vaccine to prevent HFRS in a large scale population is effective, and it is unnecessary to consider the boosting within at least 11 years after the scale population.

Key words: Hemorrhagic fever with renal syndrome, Vaccine, Long-term effect