Innovation and new technologies for measles eradication
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Innovation and new Technologies for measles eradication. Dr. David Brown Virus Reference Department HPA Microbiology services Global Measles and Rubella Management Meeting 15 th March 2011. Overview. Current status of measles control Range of research needs already identified

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Innovation and new technologies for measles eradication

Innovation and new Technologies for measles eradication

Dr. David Brown

Virus Reference Department

HPA Microbiology services

Global Measles and Rubella Management Meeting

15th March 2011


Overview

Overview

  • Current status of measles control

  • Range of research needs already identified

  • PoCT test for measles IgM

  • Molecular epidemiology – Impact of new sequencing technologies


Measles r d needs identified

Measles R&D needs Identified

  • Measles elimination:

    • Indicators for elimination/performance of surveillance programme

    • Risk factors for outbreaks

      • Waning Immunity? 2° infections

      • HIV and measles

  • Immunization Strategies

    • Changing patterns of susceptibility

    • Outbreak response immunization

    • Effectiveness of different immunization strategies

  • Laboratory Activities

    • Vaccine development

    • Antivirals

    • Diagnostics/Molecular epidemiology


  • Laboratory tools for surveillance of measles

    Laboratory tools for Surveillance of Measles:

    IgM assays and RT-PCR for confirmation of acute infections

    IgG assays to guide vaccination, serosurveys

    IgG avidity to confirm primary infections

    RT-PCR/sequencing for Molecular epidemiology

    Track epidemiological pathways

    Surveillance of virus diversity

    Investigation of potential adverse events


    Innovation and new technologies for measles eradication

    Ideal features of PoCT

    • Highly sensitive and specific

    • Rapid (15 – 30 minutes)

    • No sample preparation

    • Simple, with few operator dependent steps

    • Inexpensive

    • Clear and stable end-point result

    • Storage at room temperature

    • Results improve treatment or public health response


    Pocts available

    PoCTs available

    Bacteria

    T. pallidum

    Viruses

    H. pylori

    Strep pneumoniae

    Influenza

    Group A Strep

    RSV

    HIV

    Chlamydia trachomatis

    HBsAg

    HCV

    Biological threats

    Protozoa

    Anthrax

    Botulism

    Plague

    Malaria


    Innovation and new technologies for measles eradication

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Y

    Principle of the IgM capture near patient test

    Direction of reagent flow

    Oral fluid IgM

    Nitrocellulose

    membrane

    Test line:

    anti-human IgM

    Control line:

    Anti-mouse IgG

    rNP

    Cotton linter paper wick

    Glass fibre

    Conjugate release pad

    Plastic backing card

    Anti-NP gold conjugate


    Measles igm poct strip positive control for serum

    Measles IgM PoCT strip: positive control for serum


    Innovation and new technologies for measles eradication

    Serum measles IgM PoCT protocol

    Step1 Step 2 Step 3 Step 4 Step 5

    Dilute serum

    1/100

    Add 5µl antigen to reaction tube.

    Mix diluted serum and antigen.

    Insert test strip.

    Incubate room temp.

    Read result.


    Evaluation of measles poct for serum samples

    Evaluation of measles PoCT for serum samples:

    Sensitivity : 90.8% (95% CI 81.9 – 96.2)

    Specificity : 93.6% (95% CI 86.6 – 97.6)

    • Serum Samples:

      • 100 sera collected during measles elimination programme in Malaysia in 2004.

      • 62 sera identified as rubella IgM positive during measles surveillance in Ethiopia 2003-2004.8 cases of rubella IgM positive sera from Russia

      • PoCT vs Siemens IgM on serum samples

        • ppv 92.0 (95% CI 83.4 – 97.0)

        • npv 92.4 (95% CI 85.4 – 96.9)


    Innovation and new technologies for measles eradication

    Measles IgM PoCT: 10 Sera (# 69 – 78, incubation: 10 minutes)

    EIA results - - - - - + + + + + + +T/N ratios: 0.16 0.13 0.24 0.22 0.12 4.06 1.54 1.68 2.93 1.03 PC PC PoCT results - - - - - + + + + + +/- +/-


    Evaluation of measles poct for of samples

    Evaluation of measles PoCT for OF samples:

    • Oral fluid Samples:

      • A total of 282 OF specimens received in the UK during 2008 as part of surveillance programme. 232 received for measles investigation, 39 for rubella investigation, 11 for measles and rubella investigation.

      • PoCT performance vs MicroImmune on OF samples.

      • Sensitivity: 90.0% (95CI 80.5 – 95.8%)

    • Specificity: 96.2% (95% CI 92.6 – 98.3%)

    • ppv 88.7% (95%CI 79.0 – 95.0%)

    • npv 96.6% (95%CI 93.2 – 98.6%)


    Measles igm poct 10 oral fluid specimens 165 174 incubation 20 minutes

    Measles IgM PoCT: 10 Oral fluid specimens (#165 – 174, incubation: 20 minutes)

    EIA results - + - - - + + + - + T/N ratios:0.25 19.25 0.18 0.17 0.21 2.66 3.65 1.33 0.13 5.65PoCT results - + - - - + + + - +


    Oral fluid specimens investigated for molecular detection and characterisation after poct

    Oral fluid specimens investigated for molecular detection and characterisation after POCT


    Measles virus genomic structure

    Measles Virus Genomic Structure

    Manual for the laboratory diagnosis of measles and rubella virus infection

    WHO – EPI, WHO/IVB/07.01: 2nd edition 2007


    High throughput sequencing

    High-Throughput Sequencing

    Amplification methods now available to generate 100,000 clones from single reaction, either multiple or single samples.

    Requires high-throughput bioinformatics

    Operational Issues:

    Cost: £100 – 1000, further reductions in price likely

    Turnaround Times >7days

    From 454 life sciences website


    Measles genome sequences

    Measles Genome Sequences

    • Increasing the amount of genetic information used in phylogenetic analysis may improve the quality of inferences.

    • There are 63 full-length measles sequences in GenBank

    • Genotype distribution:

      • A 34

      • B31

      • C22

      • D316

      • D52

      • D64

      • d112

      • H11

      • H21

    • Tree generated using NJ algorithm

    • Based on N 450 only

    • Includes WHO genotype reference sequences


    Measles virus genomic diversity

    N

    H

    M

    P

    F

    LP

    Measles Virus Genomic Diversity

    Measles virus diversity along the length of the genome. Gene coding regions are shown in red.


    The next steps

    The next steps

    • Full-length measles genome sequencing would provide:

      • Greater level of genetic variation

      • Improved lineage stratification of temporally related strains

      • Mutation rate:Measles:1:6x104

      • Polio:1:1x102 Substitutions per site per year.

      • Polio mutation rate 600x measles

      • Robust phylogenies of clusters (D4 Enfield) that are not resolved by 450 nt of nucleocapsid

    • Sequence studies need to be supported by models of:

      • Sampling framework

      • Susceptible population (vaccine uptake)


    Discussion points

    Discussion points

    Measles PoCT evaluated for IgM and Virus detection/genotyping on serum and OF samples. IgM PoCT has appropriate sens/spec for field use. RT- PCR on OF extracted strips sensitive and stable (4 weeks at 22C)

    Further evaluation of PoCT with WHO AFRO gave similar results using 100 sera and OF collected in Zimbabwe surveillance programme.

    . PoCTs have potential to make a significant contribution to Measles surveillance

    Challenges-how to make widely available? ( is there a market? what cost)

    Acknowledgement: Lennesha Warender, Dhan Samuel


    Discussion points 2

    Discussion points (2)

    • Technological developments have provided a straightforward way to investigate the value of finer characterisation of virus strains.

    • Will it be useful for tracking chains of transmission.

    • Or for discriminating between multiple chains of transmissionwith closely related strains.

    • Acknowledgement: Richard Myers


    Measles control goals by who region june 2010

    Measles Control Goalsby WHO Region, June 2010

    Americas, Europe, E. Mediterranean, W. Pacific, Africa have elimination goals

    GIVS Goal:

    90% reduction in deaths

    by 2010 (vs. 2000)

    2010

    2010

    2012

    2000

    2020

    2010 SEAR RC

    Endorsed WHA 2015 targets

    Target date for elimination TBD


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