杭州市2019-2020年健康人群流行性乙型脑炎IgG抗体水平调查

IgG antibody levels against Japanese encephalitis among a healthy population of Hangzhou city in 2019-2020

目的 评估杭州市健康人群流行性乙型脑炎(乙脑)IgG抗体水平。方法 采用年龄分层随机抽样方法,于2019-2020年选择杭州市11个年龄组健康人群采集血清标本,采用酶联免疫吸附试验检测血清乙脑IgG抗体,分析抗体阳性率。结果 调查对象乙脑IgG抗体总阳性率为61.62%(411/667);各年龄组人群抗体阳性率在28.33%(20-29岁)-88.52%(3-4岁)之间(χ^(2)=46.37,P<0.001);0剂次、1剂次、2剂次、≥3剂次、不详乙脑疫苗免疫史人群抗体阳性率分别为47.06%、75.68%、74.21%、62.50%、48.91%(χ^(2)=46.37,P<0.001)。2剂次乙脑减毒活疫苗免疫史人群免疫后<1年、1年、2-3年、4-5年、≥6年乙脑IgG抗体阳性率分别为72.73%、97.06%、77.27%、83.72%、60.26%(χ^(2)=19.80,P<0.001)。结论 杭州市2019-2020年儿童乙脑抗体水平较高而青少年和成人偏低,抗体水平随乙脑疫苗免疫后时间推移呈下降趋势;需探讨青少年和成人乙脑免疫策略。

Objective To assess IgG antibody levels against Japanese encephalitis(JE) in a healthy population of Hangzhou city.Methods We used an age-stratified random sampling method to recruit healthy individuals in 11 age groups in Hangzhou during 2019-2020. We collected serum samples and tested for JE IgG antibody using an enzyme-linked immunosorbent assay to determine positivity rates.Results The overall positivity rate of JE IgG antibody was 61.62%(411/667). Positivity rates by age group ranged from 28.33% in 20-29-year-olds to 88.52% in 3-4-year-olds(χ^(2)=46.37, P<0.001). Positivity rates for subjects who had received 0, 1, 2, ≥3, and an unknown number of doses of JE vaccine were 47.06%, 75.68%, 74.21%, 62.50%, and 48.91%(χ^(2)=46.37, P<0.001), respectively. Positivity rates were 72.73%, 97.06%, 77.27%, 83.72%, and 60.26%(χ^(2)=19.80, P<0.001) among subjects who had received two doses of live attenuated JE vaccine <1, 1, 2-3, 4-5, and ≥6 years previously, respectively.Conclusions JE antibody levels were high among children but low among adolescents and adults in Hangzhou during 2019-2020, and antibody levels decreased with increasing time since JE vaccination. We should explore vaccination strategies for adolescents and adults.