Sensitivity Evaluation of a Modified Real-Time Reverse-Transcription PCR Primer to Detect a Measles Virus Variant in Japan in 2024

抄録

A measles outbreak occurred in Japan in February 2024 due to a measles virus variant imported from central Asian countries with three mismatches at the PCR reverse primer (MVN1213R) annealing site. To examine and improve the effectiveness of real-time PCR for detecting this variant, we compared the sensitivity of real-time PCR for MVN1213R and a modified primer using control RNAs, clinical isolates, and clinical specimens. The median difference in the cycle threshold value using the modified primer was 2.92 cycles lower (interquartile range, 1.99–3.38) than when using MVN1213R. Thus, PCR primer sets should be modified to effectively detect measles virus mutations.