流行性乙型脑炎减毒活疫苗人群接种后中和抗体持久性观察

Observation on Persistence of Neutralizing Antibody after Inoculation of Japanese Encephalitis Live Attenuated Vaccine in Volunteers

流行性乙型脑炎 (乙脑 )减毒活疫苗是一种安全、有效、免疫原性广的疫苗 ,其临床的保护效果得到多次观察结果证实。但乙脑活疫苗免疫持久性的观察由于工作难度大而还未见报道。为此 ,针对接种乙脑活疫苗后中和抗体持久性进行了 6年的血清学观察。结果显示 :接种疫苗前乙脑中和抗体 <1∶5的血清样本共 2 8份 ,初次免疫 1个月后中和抗体阳转率为 96 4%( 2 7/ 2 8,≥ 1∶10 )或 10 0 .0 %( 2 8/ 2 8,≥ 1∶5 ) ,加强免疫后 1个月为 10 0 0 %( 2 8/ 2 8,≥ 1∶10 ) ;加强免疫后 1年为 81 0 %( 17/ 2 1,≥ 1∶10 ) ;加强免疫后 6年抗体阳性率为 5 7 1%( 16 / 2 8,≥ 1∶10 )或75 0 %( 2 1/ 2 8,≥ 1∶5 )。表明乙脑活疫苗接种 1针 1个月后再加强免疫 1针至加强免疫后的第 6年 ,其中和抗体阳性率仍可维持在 5 7.1%～ 75 .0 %。表明乙脑活疫苗具有较好的免疫持久性。

Japanese encephalitis(JE)live attenuated vaccine(SA14-14-2 strain)is safe and effective and has a broad antigenicity.Its protective effect has been proved by many clinical observations,but its immune persistence has not been reported yet because of the difficulty of this work.We have engaged in observing the immune persistence of SA14-14-2 vaccine for 6 years.The results showed that in 28 serum samples examined,the JE neutralizing antibodies tested by 50% plague reduction neutralizing assay was<1∶5 before JE vaccine injection,the positive seroconversion rate reached 96.4%(27/28 ≥1∶10)or100%(28/28 ≥1∶5)one month after first dose of vaccine and it turned to 100%(28/28 ≥1∶10),81%(17/21 ≥1∶10)after one month and 1 year respectively after booster dose(one month apart form the first dose).After 6 years of booster dose,the antibody positive rate was 57%(16/28 ≥1∶10)or 75%(21/28 ≥1∶10).These data indicated that the JE lived attenuated vaccine(SA14-14-2 strain)can induce a persistent immune response.