Calvert N, Cutts F, Irving R, Brown D, Marsh J, Miller E
Department of Public Health Medicine, North Cumbria Health Authority, UK.
Epidemiol Infect. 1996 Feb;116(1):65-70. doi: 10.1017/s0950268800058969.
The prevalence of antibody to measles virus in 759 children aged 11-18 years attending a secondary school in Cumbria was measured using a salivary IgG antibody capture assay. Serum IgG antibody levels were measured using a plaque reduction neutralization assay in subjects whose saliva was antibody negative. Vaccination histories were obtained from the child health computer and general practice record. A total of 662 pupils (87% of those tested) had detectable measles-specific IgG in saliva. Of the remaining 97, 82 provided blood samples and 29 had serum neutralizing antibody levels above 200 mIU/ml. Afer adjusting for non-participation rates, the proportion considered non-immune (no IgG in saliva and < or = 200 mIU/ml in serum) was 9% overall, ranging from 6% in vaccinated children to 20% in unvaccinated children. Measles-mumps-rubella vaccine was given to 50 children of whom 38 provided post-vaccination serum and 32 saliva samples. Thirty (79%) had a fourfold or greater rise in serum neutralizing antibody and 28 (88%) developed IgG antibody in saliva. Half of the children considered non-immune by antibody testing would have been overlooked in a selective vaccination programme targeted at those without a history of prior vaccination. A programme targeted at all school children should substantially reduce the proportion non-immune since a primary or booster response was achieved in three quarters of previously vaccinated children with low antibody levels and in all unvaccinated children. While it is feasible to screen a school-sized population for immunity to measles relatively quickly using a salivary IgG assay, a simple inexpensive field assay would need to be developed before salivary screening and selective vaccination could substitute for universal vaccination of populations at risk of measles outbreaks. The salivary IgG assay provided a sensitive measure of a booster response to vaccination.
采用唾液IgG抗体捕获试验，对坎布里亚郡一所中学759名11至18岁儿童的麻疹病毒抗体流行情况进行了检测。对唾液抗体呈阴性的受试者，采用蚀斑减少中和试验检测血清IgG抗体水平。从儿童健康计算机系统和全科医疗记录中获取疫苗接种史。共有662名学生（占检测人数的87%）唾液中可检测到麻疹特异性IgG。其余97名学生中，82名提供了血样，29名血清中和抗体水平高于200 mIU/ml。在对未参与率进行校正后，总体上被认为无免疫力（唾液中无IgG且血清中≤200 mIU/ml）的比例为9%，接种疫苗儿童中为6%，未接种疫苗儿童中为20%。50名儿童接种了麻疹-腮腺炎-风疹疫苗，其中38名提供了接种后血清样本，32名提供了唾液样本。30名（79%）血清中和抗体有四倍或更大幅度升高，28名（88%）唾液中产生了IgG抗体。在针对无既往接种史者的选择性疫苗接种计划中，通过抗体检测被认为无免疫力的儿童中有一半会被遗漏。针对所有在校儿童的计划应能大幅降低无免疫力者的比例，因为四分之三既往抗体水平较低的接种疫苗儿童以及所有未接种疫苗儿童都出现了初次或加强免疫反应。虽然使用唾液IgG检测法相对快速地筛查学校规模人群的麻疹免疫力是可行的，但在唾液筛查和选择性疫苗接种能够替代对有麻疹暴发风险人群的普遍疫苗接种之前，需要开发一种简单廉价的现场检测方法。唾液IgG检测法为疫苗接种的加强免疫反应提供了一种灵敏的测量方法。
