Observation on the Safty and Efficay of Inactivated Vaccine(Type Ⅱ) against HFRS

To study the safty,efficacy and antibody dependenc-enhance-ment(ADE) of inactivated vaccine(TypeⅡ) prepared fromg olden hamster kidne cell(GHKC) against HFRS,6140 healthy people,whose age was 16 to 60 years old,was injected three times on 0,28 day and 42,at 10 villages of Chian township,Fengxin county in 1994,which was made asupplementdery injection in 1995.The study was observed 4 years.The level of antibody in serum,after the third injection,the neutralization antibody(1:50positive rates was 88.24%,its geometric mean titer(GMT) of neutralization antibody was 12.51.IFA(1:10) antibody positive rates was 76.32% and its GMT was 13.15.two weeks,1 years,2 years,3years after the forth injection,the neutralization antibody positive rates were 100%、47.05%、30.76% and 30.76%.Their GMT were 14.34、4.08、3.09 and 3.09 serocnversion of IFA antibody(three times) were 100%、58.82%、53.84% and 30.76% respectively.the GMT of them were 72.19、10.42、8.08 and 6.52these data demonstrated that the vaccine could effectively induce specfic antibody response and the vaccine had a satisfied effect against HFRS in middle-short perioed.The reactions of injection were slight and localreactions only found in few people.It shows that the vaccine was safe.As is shown in the during which we injected to those who had infected,survied the case who completed his vaccination of full doses,observed changed-level of the antibody in serum both fomer and the later which at the Spring and the Autumn peaks of HFRS in 1997;there to be no ADE in these groups.There were 61 cases of HF RS in the control group and 1cases in the test group,making the incidence 178.55/10sup>5,16.29/10⁵,and the protection rate were 97.72%.For the first time,the study revealed that the vaccine type Ⅱ had satisfactory effect in the epidemic area of mix type.