2017年贵州省少数民族地区健康人群乙型脑炎中和抗体水平调查

Neutralizing antibody levels against Japanese encephalitis virus among healthy people in ethnic minority areas of Guizhou province, 2017

目的调查贵州省少数民族地区健康人群流行性乙型脑炎(乙脑)中和抗体水平。方法采用多阶段随机抽样方法在2017年6-9月抽取3个少数民族自治州8个年龄组健康人群,应用蚀斑减少中和试验检测血清乙脑中和抗体,分析抗体阳性率和几何平均滴度(GMT)。结果调查对象乙脑中和抗体阳性率为65.21%(313/480),GMT为1:10.06(95%CI:1:8.48-1:11.94)。男、女性抗体阳性率分别为60.26%、69.72%(χ^2=4.72,P=0.030),GMT分别为1:8.27、1:12.04(Z=-2.16,P=0.031);年龄别抗体阳性率在51.67%(11-15岁、31-40岁)-81.67%(≥41岁)之间(χ^2=20.05,P=0.005),GMT在1:4.90(11-15岁)-1:23.26(≥41岁)之间(χ^2=28.57,P<0.001);不同地区抗体阳性率在58.13%-73.13%之间(χ^2=8.01,P=0.018),GMT在1:6.59-1:14.09之间(χ^2=14.73,P=0.001)。结论贵州省少数民族地区健康人群(特别是11-15岁和31-40岁)乙脑中和抗体水平低,建议针对重点人群适时开展乙脑疫苗补充免疫。

Objective To determine neutralizing antibody levels against Japanese encephalitis(JE)among healthy people in ethnic minority areas of Guizhou province.Methods We used a multi-stage random sampling method to select healthy people in 8 age groups f rom 3 ethnic minority autonomous prefectures in June to September 2017.We tested serum samples for JE neutralizing antibodies using the plaque reduction neutralization test,and we conducted analyses of antibody positivity rates and geometric mean titers(GMTs).Results The positivity rates and GMTs of JE neutralizing antibody were 65.21%(313/480)and 1:10.06(95%CI:1:8.48-1:11.94),respectively.Positivity rates for males and females were 60.26%and 69.72%,respectively(χ^2=4.72,P=0.030),and GMTs were 1:8.27 and 1:12.04(Z=-2.16,P=0.031).Positivity rates and GMTs by age ranged 51.67%(11-15 and 31-40-year-olds)-81.67%(≥41-year-olds)(χ^2=20.05,P=0.005),and 1:4.90(11-15-year-olds)-1:23.26(≥41-year-olds)(χ^2=28.57,P<0.001),respectively.Positivity rates and GMTs by region were 58.13%-73.13%(χ^2=8.01,P=0.018)and 1:6.59-1:14.09(χ^2=14.73,P=0.001),respectively.Conclusions JE neutralizing antibody levels were low among healthy people(especially among 11-15 and 31-40-year-olds)in ethnic minority areas of Guizhou.We recommend supplemental immunization with JE vaccine for priority people.