Stanoeva Kamelia R, Kohl Robert H G, Bodewes Rogier
Centre for Infectious Disease Research, Diagnostics and laboratory Surveillance (IDS), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
European Public Health Microbiology Training Programme (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
Access Microbiol. 2021 Nov 5;3(11):000283. doi: 10.1099/acmi.0.000283. eCollection 2021.
In rare cases vaccination with the measles virus vaccine genotype A (MeVA) may cause a vaccine reaction with clinical signs similar to infection with wild-type measles virus (MeVwt). Rapid differentiation between MeVA and MeVwt infection is important for taking adequate public health measures. Recently, a few MeVA real-time reverse-transcription quantitative PCR methods (RT-qPCRs) were described that can distinguish between MeVA and MeVwt. However, detection of MeVA does in theory not exclude infection with MeVwt. In the present study, we established a protocol for determination of co-infections with MeVA and MeVwt. To this end, MeVA RT-qPCRs were used in combination with the routine measles virus (MeV) RT-qPCR, and the results suggested that the differences between the RT-qPCR Ct values (delta Ct, ∆Ct) could be used as criteria. Subsequently, we tested samples from vaccine-associated measles cases that were confirmed by genotyping. In addition, experimental mixtures of MeVA and MeVwt were tested in different concentrations. All tested MeVA clinical samples had ∆Ct ≤3.6. The results of experimental mixtures showed a mean ∆Ct ≤2.8 for genotype A alone and >3.2 when combined with either genotype B3 or D8. The results of a receiver operator characteristic analysis indicated that the optimum ∆Ct for use as a cut-off value was 3.5, while with ∆Ct values of 2.9 and 3.7 sensitivity and specificity were respectively 1.00. Thus, ∆Ct could be used to exclude the presence of MeVwt if MeVA is detected and ∆Ct is <2.9, while ∆Ct >3.7 were highly suggestive of co-infection and ≥2.9 ∆Ct <3.7 warranted additional confirmation, such as next-generation sequencing. This RT-qPCR-based protocol could be used for the exclusion of infection with MeVwt in cases with vaccine-associated measles reaction, crucial for the timely implementation of public health prevention and control measures.
在极少数情况下，接种麻疹病毒疫苗基因型A（MeVA）可能会引发疫苗反应，其临床症状与野生型麻疹病毒（MeVwt）感染相似。快速区分MeVA和MeVwt感染对于采取适当的公共卫生措施至关重要。最近，有一些MeVA实时逆转录定量PCR方法（RT-qPCR）被描述出来，这些方法可以区分MeVA和MeVwt。然而，从理论上讲，检测到MeVA并不排除MeVwt感染。在本研究中，我们建立了一种用于确定MeVA和MeVwt合并感染的方案。为此，将MeVA RT-qPCR与常规麻疹病毒（MeV）RT-qPCR结合使用，结果表明RT-qPCR Ct值之间的差异（delta Ct，∆Ct）可作为判断标准。随后，我们对通过基因分型确诊的疫苗相关麻疹病例的样本进行了检测。此外，还对不同浓度的MeVA和MeVwt的实验混合物进行了测试。所有检测的MeVA临床样本的∆Ct≤3.6。实验混合物的结果显示，单独的基因型A的平均∆Ct≤2.8，与基因型B3或D8联合时>3.2。受试者操作特征分析的结果表明，用作临界值的最佳∆Ct为3.5，而当∆Ct值为2.9和3.7时，敏感性和特异性分别为1.00。因此，如果检测到MeVA且∆Ct<2.9，则可以使用∆Ct排除MeVwt的存在，而∆Ct>3.7高度提示合并感染，2.9≤∆Ct<3.7则需要进一步确认，如下一代测序。这种基于RT-qPCR的方案可用于在疫苗相关麻疹反应病例中排除MeVwt感染，这对于及时实施公共卫生预防和控制措施至关重要。
