Laboratory diagnosis of vaccine-associated measles in Zhejiang Province, China

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J Microbiol Immunol Infect. 2015 Nov 19. pii: S1684-1182(15)00899-3. doi: 10.1016/j.jmii.2015.10.004. [Epub ahead of print]

Laboratory diagnosis of vaccine-associated measles in Zhejiang Province China.

Xu CP¹ Li MH¹ He HQ¹ Lu YY¹ Feng Y².

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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.