Chang-Ping Xu1, Min-Hong Li1, Han-Qing He1, Yi-Yu Lu1, Yan Feng2. 1. Key Laboratory of Emergency Detection for Public Health of Zhejiang Province, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China. 2. Key Laboratory of Emergency Detection for Public Health of Zhejiang Province, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China. Electronic address: fengyanzjh@aliyun.com.
Abstract
BACKGROUND/ PURPOSE: Along with the improving vaccine coverage, suspected vaccine-associated measles has been reported in Zhejiang Province, China. In order to maintain the accuracy of the measles surveillance system, it is critical to discriminate between measles vaccine and wild-type virus. METHODS: Eight suspected cases of vaccine-associated measles were reported in Zhejiang Province during 2011 and 2014. Sera collected within 4 days and throat swabs collected within 6 days after rash onset were tested with immunoglobulin M and measles virus (MeV) RNA to confirm MeV infection. In order to further identify the vaccine-associated cases, throat swabs with positive MeV RNA were tested using an allelic discrimination real-time reverse transcriptase polymerase chain reaction (rRT-PCR) assay developed in this study, RT-PCR-restriction fragment length polymorphism (RFLP) recommended by the National Measles Laboratory, and RT-PCR followed by sequencing and genotyping. RESULTS: Combining anti-measles immunoglobulin M and RNA testing, eight cases were confirmed as MeV infection. Of the eight, two were identified as vaccine-associated cases by the allelic discrimination rRT-PCR assay, and one was identified by RT-PCR-RFLP. Subsequent sequencing and genotyping confirmed that the sequences of the two cases were identical to that of the Chinese vaccine strain. The developed allelic discrimination rRT-PCR was 10 times more sensitive than the RT-PCR-RFLP assay when RNA standards generated from three genotypes of MeV were tested. CONCLUSION: Vaccine-associated measles has been identified in Zhejiang. The developed allelic discrimination rRT-PCR assay is rapid and sensitive, which will facilitate the surveillance for vaccine-associated measles.
BACKGROUND/ PURPOSE: Along with the improving vaccine coverage, suspected vaccine-associated measles has been reported in Zhejiang Province, China. In order to maintain the accuracy of the measles surveillance system, it is critical to discriminate between measles vaccine and wild-type virus. METHODS: Eight suspected cases of vaccine-associated measles were reported in Zhejiang Province during 2011 and 2014. Sera collected within 4 days and throat swabs collected within 6 days after rash onset were tested with immunoglobulin M and measles virus (MeV) RNA to confirm MeV infection. In order to further identify the vaccine-associated cases, throat swabs with positive MeV RNA were tested using an allelic discrimination real-time reverse transcriptase polymerase chain reaction (rRT-PCR) assay developed in this study, RT-PCR-restriction fragment length polymorphism (RFLP) recommended by the National Measles Laboratory, and RT-PCR followed by sequencing and genotyping. RESULTS: Combining anti-measles immunoglobulin M and RNA testing, eight cases were confirmed as MeV infection. Of the eight, two were identified as vaccine-associated cases by the allelic discrimination rRT-PCR assay, and one was identified by RT-PCR-RFLP. Subsequent sequencing and genotyping confirmed that the sequences of the two cases were identical to that of the Chinese vaccine strain. The developed allelic discrimination rRT-PCR was 10 times more sensitive than the RT-PCR-RFLP assay when RNA standards generated from three genotypes of MeV were tested. CONCLUSION: Vaccine-associated measles has been identified in Zhejiang. The developed allelic discrimination rRT-PCR assay is rapid and sensitive, which will facilitate the surveillance for vaccine-associated measles.
Authors: Nicklas Sundell; Leif Dotevall; Martina Sansone; Maria Andersson; Magnus Lindh; Thomas Wahlberg; Tobias Tyrberg; Johan Westin; Jan-Åke Liljeqvist; Tomas Bergström; Marie Studahl; Lars-Magnus Andersson Journal: Euro Surveill Date: 2019-04