Bureau of Immunization, New York City Department of Health and Mental Hygiene, New York.
Clin Infect Dis. 2014 May;58(9):1205-10. doi: 10.1093/cid/ciu105. Epub 2014 Feb 27.
Measles was eliminated in the United States through high vaccination coverage and a public health system able to rapidly respond to measles. Measles may occur among vaccinated individuals, but secondary transmission from such individuals has not been documented.
Suspected patients and contacts exposed during a measles outbreak in New York City in 2011 were investigated. Medical histories and immunization records were obtained. Cases were confirmed by detection of measles-specific immunoglobulin M and/or RNA. Tests for measles immunoglobulin G (IgG), IgG avidity, measurement of measles neutralizing antibody titers, and genotyping were performed to characterize the cases.
The index patient had 2 doses of measles-containing vaccine; of 88 contacts, 4 secondary patients were confirmed who had either 2 doses of measles-containing vaccine or a past positive measles IgG antibody. All patients had laboratory confirmation of measles infection, clinical symptoms consistent with measles, and high-avidity IgG antibody characteristic of a secondary immune response. Neutralizing antibody titers of secondary patients reached >80 000 mIU/mL 3-4 days after rash onset and that of the index was <500 mIU/mL 9 days after rash onset. No additional cases of measles occurred among 231 contacts of secondary patients.
This is the first report of measles transmission from a twice-vaccinated individual with documented secondary vaccine failure. The clinical presentation and laboratory data of the index patient were typical of measles in a naive individual. Secondary patients had robust anamnestic antibody responses. No tertiary cases occurred despite numerous contacts. This outbreak underscores the need for thorough epidemiologic and laboratory investigation of suspected cases of measles regardless of vaccination status.
美国通过高疫苗接种率和能够快速应对麻疹的公共卫生系统消除了麻疹。麻疹可能在接种过疫苗的人群中发生，但尚未记录到此类人群的继发传播。
对 2011 年纽约市麻疹暴发期间的疑似患者和接触者进行了调查。获取了病史和免疫接种记录。通过检测麻疹特异性免疫球蛋白 M 和/或 RNA 来确认病例。对麻疹免疫球蛋白 G（IgG）、IgG 亲和力、麻疹中和抗体滴度的测量以及基因分型进行了测试，以对病例进行特征描述。
索引患者接种了 2 剂麻疹疫苗；在 88 名接触者中，有 4 名继发患者被确诊，他们要么接种了 2 剂麻疹疫苗，要么过去曾有麻疹 IgG 抗体阳性。所有患者均经实验室确认感染麻疹，具有麻疹临床症状，且 IgG 抗体亲和力高，这是继发免疫反应的特征。继发患者的中和抗体滴度在出疹后 3-4 天达到>80000 mIU/mL，而指数患者在出疹后 9 天的滴度<500 mIU/mL。在继发患者的 231 名接触者中，未发生其他麻疹病例。
这是首次报告由记录的继发疫苗失败的两次接种个体传播麻疹。索引患者的临床表现和实验室数据是麻疹在无免疫个体中的典型表现。继发患者具有强大的记忆抗体反应。尽管接触者众多，但没有发生三级病例。此次暴发突出表明，无论接种状况如何，都需要对疑似麻疹病例进行彻底的流行病学和实验室调查。
