Article Figures & Data
Figures
- FIG 1
Primer and probe design for the measles vaccine rRT-PCR targeting the N gene. The primer and probe location and sequence used in the measles vaccine real-time PCR are boxed. Strains 1 to 9 are vaccine strains. Edmonston wild-type genotype A is represented as strain 10. Strains 11 to 37 are WHO wild-type reference genotype strains. An asterisk (*) denotes an alternative reference strain. Identical nucleotides compared to the Edmonston-derived vaccine strains (Enders/Moraten, Schwarz, and Rubeovax) are represented with dots. Nucleotide differences compared to Edmonston-derived vaccine strains are shown and are indicated as the dNTP base.
- FIG 2
Amplification profiles of wild-type Edmonston strain (genotype A) measles on measles rRT-PCR and measles vaccine rRT-PCR. The dashed line shows the amplification plot generated by the measles rRT-PCR, and the solid line shows the deformed amplification plot generated by measles vaccine real-time PCR. The solid horizontal line is the cycle threshold line from which amplification curves cross to generate CT values.
- FIG 3
Monthly distribution of measles PCR testing and measles genotyped cases from January 2014 to November 2017.
Tables
- TABLE 1
Primers and probes for measles vaccine rRT-PCR, measles rRT-PCR, and measles genotyping RT-PCR
Method Primer or probea 5′–3′ nucleotide sequence Measles vaccine rRT-PCR MeVAvac-F CGGCACACCCCTAGACATTG MeVAvac-R TCCTGCCATGGCTTGCA MeVAvac-P FAM-CTGCAACGGAGTCC-MGBNFQ Measles rRT-PCR MeV-F TGGCATCYGAACTCGGTATCAC MeV-R TGTCCTCAGTAGTATGCATTGCAA MeV-P FAM-CCGAGGATGCAAGGCTWGTTTCAGA-TAMRA Measles genotyping RT-PCR MeV216-F TGGAGCTATGCCATGGGAGT MeV214-R TAACAATGATGGAGGGTAGG ↵a F, forward primer; R, reverse primer; P, probe.
- TABLE 2
Sensitivity of detection for vaccine straina
↵a Serial log10 dilutions of cDNA from measles vaccine (MMR II-CSL) used to assess the limit of detection for all PCR assays. Dilutions (10−3 to 10−5) of the measles vaccine strain were tested in 20 replicates, with results shown in parentheses. Shaded boxes indicate reproducible detection of measles virus RNA. Nonreproducible detection of measles virus RNA shown in boldface. Unshaded boxes indicate that measles virus RNA was not detected.
bMMR II (CSL Limited/Merck and Co., Inc.).
- TABLE 3
Comparison of specificity and sensitivity of wild-type Edmonston strain (genotype A) detection in the measles rRT-PCR and the measles vaccine rRT-PCR
Measles Edmonston wild-type strain Viral RNA detection results bya: Measles rRT-PCR (CT value) Measles vaccine rRT-PCR (CT value) Neat Detected (30) Detected (44) 10−1 dilution Detected (33) Not detected 10−2 dilution Detected (37) Not detected 10−3 dilution Not detected Not detected 10−4 dilution Not detected Not detected ↵a Real-time PCR cycle threshold (CT) values are provided in parentheses.
- TABLE 4
Specificity of the measles vaccine rRT-PCR to vaccine strain, wild-type Edmonston strain (genotype A) and other circulating wild-type genotypes of measles virus
Measles genotype Detection results by:a Measles rRT-PCR (CT value) Measles vaccine rRT-PCR (CT value) A-vaccine Detected (25) Detected (25) A-wild type Detected (25) Detected (41)b B3 Detected (23) Not detected D3 Detected (21) Not detected D4 Detected (24) Not detected D5 Detected (21) Not detected D7 Detected (23) Not detected D8 Detected (19) Not detected D9 Detected (20) Not detected G3 Detected (25) Not detected H1 Detected (21) Not detected H2 Detected (17) Not detected - TABLE 5
No. of measles cases and measles genotyped cases from prospective parallel testing of clinical specimens from January 2014 to November 2017
No. of cases Time period January 2014–September 2015 October 2015–November 2017 Measles cases 299 172 Measles cases, genotyped/untypeable 272/27 162/10 Measles vaccine case investigations 46 105 Measles vaccine case investigations positive by measles rRT-PCR/measles vaccine rRT-PCR/measles genotyping PCR 27/27/25 40/40/NAa ↵a NA, measles genotyping PCR not performed.
