论文部分内容阅读
目的探讨陕西省麻疹高接种率下高发病率的病原学和疫苗免疫相关因素。方法分析麻疹病例年龄及免疫史。从咽拭子中分离病毒,用酚-氯仿抽提法提取病毒RNA,逆转录-聚合酶链反应(RT-PCR)扩增N基因-COOH端的450个核苷酸(bp)片段,进行序列测定和基因分型。用微量中和试验测定疫苗免疫血清及麻疹病例急性期血清中和疫苗株和野毒株的抗体水平。结果麻疹病例中有麻疹疫苗免疫史的平均占38.97%;麻疹病例急性期血清:有免疫史的中和S191株GMT (56.18)明显高于H1野毒株GMT(26.90);无免疫史的S191株GMT(25.40)与H1野毒株(27.86)相近。疫苗免疫血清:S191株抗体效价≤16血清中有19.15%为H1野毒株抗体阴性。结论陕西省近年出现的麻疹高接种率水平下的高发病率现象不排除麻疹流行株变异和疫苗对流行株H1基因组野毒株保护性不足两方面因素。
Objective To explore the etiological and immunological factors related to the high incidence of measles at high vaccination rates in Shaanxi Province. Methods To analyze the age and immunization history of measles cases. The virus was isolated from the throat swab and the viral RNA was extracted by phenol-chloroform extraction. The 450 nucleotides (bp) fragment of the N gene-COOH end was amplified by reverse transcription-polymerase chain reaction (RT-PCR) Assay and genotyping. Antibody levels of both vaccine and wild-type serums were determined using a minimal neutralization assay in the serum of the vaccine and in the acute phase of the measles case. Results The average measles vaccine immunization history in measles cases accounted for 38.97% of the total. Measles cases with acute sera: the neutralizing S191 strain immunized with GMT (56.18) was significantly higher than that of H1 wild-type strain GMT (26.90); S191 Strains of GMT (25.40) were similar to H1 (27.86). Vaccine immune serum: S191 antibody titer ≤ 16 serum 19.15% of the H1 wild-type antibody negative. Conclusions The high morbidity rate of measles vaccination in Shaanxi Province in recent years does not exclude the variation of measles epidemic strains and the lack of protective effect of the vaccine against the wild type H1 virus genome strains.