[Long term epidemiological effects of vaccination on hemorrhagical fever with renal syndrome (HFRS) in Shaanxi provincial HFRS epidemic areas].

Objective: To evaluate the protective rate and the variation of HFRS-IgG on hemorrhagical fever with renal syndrome (HFRS) vaccine.

Methods: Cluster, random sampling and cross-sectional study were used to assess the protective rate of HFRS vaccination. Level of HFRS-IgG was detected with ELISA in epidemic and non-epidemic areas of HFRS.

Results: Curve equation was obtained as Yprotective rate=(0.863+0.283/Xvaccination term)×100% by protective rate with vaccination term. Protective rates showed a reducing trend, 90% after 7-8 years of vaccination, 88% after 10 years, and 94% on average. Absorbance (A) value of HFRS-IgG was 4 times higher in persons with vaccination than those without, in the epidemic area. Higher antibody level could be obtained after primary vaccination, but the level of antibody had a 50% reduction after 5-10 years of vaccination, and a 60% reduction after 10 years of vaccination.

Conclusion: HFRS antibody had a 50% reduction after 5-10 years of vaccination. The protective rate of HFRS vaccination had a 90% loss, after 7-8 years of vaccination. Booster dose was necessary after 7 years of vaccination.