Freed Nikki E, Myers Christopher A, Russell Kevin L, Walter Elizabeth A, Irvine Marina, Coon Robert G, Metzgar David
Department of Defense Center for Deployment Health Research, Naval Health Research Center, San Diego, CA 92186-5122, USA.
Mol Cell Probes. 2007 Apr;21(2):103-10. doi: 10.1016/j.mcp.2006.08.007. Epub 2006 Sep 8.
Live vaccines can generate false-positive results on common influenza assays including reverse transcriptase-PCR (RT-PCR), culture and antigen tests. This threatens the integrity of epidemiological data and may misdirect treatment and control efforts. We report the development of RT-PCR tests that distinguish live FluMist vaccine (FMV) strains from circulating influenza strains in clinical samples. Primers were validated using influenza-positive samples from unvaccinated patients, packaged FMV, and one PCR-positive asymptomatic vaccine. Furthermore, the assay was used to experimentally test our lab's collection of influenza-positive samples from the 2004-05 and 2005-06 influenza seasons and several 2005 preseason isolates to determine the rate of vaccine-derived false-positive results under differing epidemiological conditions. Analytical and clinical validations show that the assay is both sensitive and specific. Experimental results demonstrate that 51 out of 51 influenza-positive samples collected during influenza season from ill, previously-vaccinated military personnel represent real infections with circulating strains. Finally, the assay shows that four preseason influenza-positive samples were false positives resulting from vaccine shedding. The vaccine-discriminatory RT-PCR methods described here provide the first test designed to distinguish FMV strains from circulating strains. The results show that the test is effective, and demonstrate the importance of such tests in the age of live vaccines.
活疫苗可能会在包括逆转录聚合酶链反应（RT-PCR）、培养和抗原检测在内的常见流感检测中产生假阳性结果。这威胁到了流行病学数据的完整性，可能会误导治疗和防控工作。我们报告了一种RT-PCR检测方法的研发，该方法能够区分临床样本中活的流感喷雾疫苗（FMV）毒株和正在传播的流感毒株。使用来自未接种疫苗患者的流感阳性样本、包装好的FMV以及一份PCR阳性的无症状疫苗样本对引物进行了验证。此外，该检测方法还用于对我们实验室收集的2004 - 05年和2005 - 06年流感季节的流感阳性样本以及2005年几个季前分离株进行实验测试，以确定在不同流行病学条件下疫苗衍生假阳性结果的发生率。分析和临床验证表明该检测方法既灵敏又特异。实验结果表明，在流感季节从患病的、之前接种过疫苗的军事人员中采集的51份流感阳性样本均为感染了正在传播的毒株的真实病例。最后，该检测方法表明，4份季前流感阳性样本是由疫苗排毒导致的假阳性。这里描述的区分疫苗的RT-PCR方法提供了首个旨在区分FMV毒株和正在传播的毒株的检测方法。结果表明该检测方法是有效的，并证明了此类检测方法在活疫苗时代的重要性。
