Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.

Dr Kirsty Le Doare @ MRF's Meningitis & Septicaemia

6 512 vues

Publié le

Prospects for GBS prevention - current candidates & removing barriers to licensure of a GBS vaccine for pregnant women globally

Publié dans : Santé & Médecine
  • Login to see the comments

  • Soyez le premier à aimer ceci

Dr Kirsty Le Doare @ MRF's Meningitis & Septicaemia

  1. 1. Prospects for GBS prevention - current candidates & removing barriers to licensure of a GBS vaccine for pregnant women globally. Kirsty Le Doare Centre for International Child Health, Imperial College London Thank you to Prof Shabir Madhi and Prof Joy Lawn for sharing slides to be included in this presentation
  2. 2. Why this organism ? #GBSburden #momandbaby • Commonly found in gut or lower vaginal tract • Leading cause of neonatal infections Early Onset and Late Onset (sepsis, meningitis) in many countries with high case fatality rate
  3. 3. Meningitis in young infants GBS: 86% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% <2mo Percentageoftotalcases GBS: 78% USA 2003-07 UK & ROI 2010-11Cases < 2 months of age NEJM 2011; 364: 2016-2025 Clin Infect Dis 2014;15; 59(10):50-7
  4. 4. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2002 2004 2006 2008 2010 2012 2014 Intrapartum Antibiotic Prophylaxis (IAP) Reduces Early-Onset Disease (EOD), but does Not Prevent Late-Onset-Disease (LOD) Rate of Early- and Late-Onset GBS, US 1990-2014* *CDC Active Bacterial Core surveillance / Emerging Infections Program Early-onset GBS ~80% reduction of early-onset disease Late-onset GBS IAP effectiveness continues to plateau in 2016* Before national prevention policy Transition Universal screening ~30% of pregnant women receive antibiotics
  5. 5. Why pursue a maternal GBS vaccine? 1. Higher impact than IAP as affects more outcomes 2. Higher coverage especially in challenging settings  more equitable than IAP 3. Leverage existing programmatic platforms (e.g. antenatal care) 4. Reduce antibiotic exposure (21.7 million women) Could be prevented by IAP Could be prevented by maternal GBS vaccine
  6. 6. MI COMPLEMENTS EXISTING VACCINES AND INTERVENTIONS1 IN THE CONTINUUM OF MOTHER-INFANT CARE MI could be a key component of the continuum of care Vulnerability zone (up to 3 months) Too early for childhood vaccines Continuum of care Obstetric, childbirth, and essential newborn care Clean birth In-facility and community ANC Neonatal sepsis prevention and treatment Pregnancy home visit Pregnancy Infant Childhood vaccines / EPI 6 wksBirth 10 wks 14 wks Protection from maternal immunization MI may provide protection until childhood vaccines Early and late postnatal care for mother and newborn Care of newborn, infant and child GBS RSV Tetanus 1. Maternal Newborn Child Health; Source: Every Newborn: An action plan to end preventable deaths (2013).
  7. 7. Vaccines targeting disease-associated bacterial antigens can reduce severe disease and clones associated with antimicrobial resistance © Bill & Melinda Gates Foundation | Acquisition of Tetracycline resistance (TcR) led to expansion of hypervirulent CC17 clones followed by the emergence of neonatal GBS disease in the 1960s1 1Da Cunha V, Nat comm 2017; 2Almeida A, msystems ASM 2017 - In HIC ~32% of pregnant women receive intrapartum antibiotics (Penicillin) to protect their newborn infants against GBS disease - Emerging resistance to second-line antibiotics Presence of CC17 correlates with cases of LOD and meningitis2 GBS glyco-conjugate vaccine targeting CC17 isolates (Type III and IV) Decreased use of antibiotics and less severe disease Severe GBS disease Potential resistance
  8. 8. Basis for immunological intervention of invasive GBS disease in infants • IgG antibodies are uniquely transferred to the fetus during the 3rd trimester1,2 • Functional anti-CPS antibodies may protect the mother from infection and prevent acquisition of new strains via opsonophagocytosis3 1Palmeira et al. 2012; Clin Dev Immunol 985646; 2Roopenian 2007; Nature Rev Immunol 7, 715; 3Baltimore et al 1977; J Immunol 118, 673
  9. 9. How many GBS deaths could be prevented? 0 20 40 60 80 100 120 Maternal GBS disease deaths Stillbirths with GBS Early onset GBS deaths Late onset GBS deaths Deathsprevented(thousands) Not estimated Current approach (IAP) prevents 29 000 (UR, 0–51 ]000) early onset GBS cases A maternal vaccination could prevent 231 000 (UR, 114 000–507 000) infant and maternal GBS cases, 41 000 (UR, 8000–75 000) stillbirths , 66 000 (UR, 12 000–123 000) infant deaths Seale AC et al Clinical Infectious Diseases. 2017;65(S2):S200-19
  10. 10. Example of vaccine cost-effectiveness
  11. 11. Where do we go from here? Focus area Activity Improved data on the burden - Neonatal and stillbirth cause-of-death studies eg CHAMPS network - Cohort studies for impairment outcomes - Whole genome sequencing Value proposition - Global value proposition, WHO - Additional burden and Cost-effectiveness modeling Vaccine development - Validate path to licensure Policy, guidance and norms - WHO Preferred Product Characteristics, technical R&D roadmap - Support for WHO activities to facilitate GBS vaccine development, licensure, and prequalification with a focus on LMIC Standardised assays for assessment of a correlate - International collaboration to harmonise reagents and methods for the assessment of antibody against GBS - Aim to predict a serocorrelate of protection against disease for the most common serotypes
  12. 12. Momentum since PDVAC 2016 on GBS 1. Develop preferred product characteristics (PPC) for GBS vaccine 2. Finalisation of the GBS Vaccine Development Technology Roadmap 3. Advance planning for WHO pre-qualification, policy making, implementation: • Identify key gaps and define implementation research agenda • Need to build stakeholder commitment, a GBS vaccine community 4. Completion of global burden of disease estimates – maternal, stillbirths and infants. 5. Work-in-progress on GBS assay standardisation, including reference sera. 6. Further reports on tri-valent GBS vaccine in pregnant women, including antibody kinetics in women and infants, and impact of interference to childhood vaccines. 7. Phase I study on GBS common protein (AlpC and Rib) vaccine in pregnant women, and first-in-human studies of higher valency (>3 serotypes) polysaccharide-protein conjugate vaccine.
  13. 13. GBS is an underestimated cause of neonatal infection, maternal infection and stillbirth Courtesy: Anna Seale & Joy Lawn • 33,000 maternal disease • 57,000 stillbirths • 319,000 infant disease • 90,000 infant deaths
  14. 14. Value Proposition of GBS (and other)Maternal Immunization (MI) 4 MI may protect infants <5-mo against infection-related deaths MI may also prevent a portion of preterm birth and infection- related stillbirths (10 – 50%1 of the overall stillbirths) MI can have an impact on maternal morbidity and mortality 1. McClure EM, "Stillbirth in Developing Countries: A review of causes, risk factors and prevention strategies" , J. of Matern Fetal Neonatal Med. (2014); 2. WHO-CHERG 2013 Global neonatal mortality2 Infection related 606K (22%) Pre-term births 965K (35%) Other 1,190K (43%)
  15. 15. GBS vaccine development pipeline © Bill & Melinda Gates Foundation | http://www.who.int/immunization/research/development/ppc_grou pb_strepvaccines/en/
  16. 16. Newborn antibody concentrations 49–79% of maternal levels 0 2.5 5 7.5 10 GMC (ug/ml) 30-32wk delivery cord infant1month infant2months GBS conjugate vaccines in pregnant women
  17. 17. GBS Serotype Ia antibodies In HIV-uninfected and HIV-infected Mothers and their infants with one 5.0 µg dose of GBS vaccine Mothers InfantsELISAGMC(µg/mL) HIV+ High CD4+ HIV+ low CD4+HIV uninfected Day 1 Day 15 Day 31Delivery 0 2 4 6 8 10 Day 1 Day 42 0 2 4 6 8 10 Similar immunogenicity trends observed for serotypes Ib and III Transfer Ratio 0.72 (0.61–0.85) 0.58 (0.49–0.69) 0.60 (0.51–0.72) Adapted: Heyderman R, Madhi SA et al. Lancet Infect Dis 2016; 16: Increased risk of invasive GBS Disease in HIV-exposed infants: Early-onset disease: RR: 1.69 (95%CI: 1.3-2.2) Late-onset disease: RR: 3.18 (95%CI: 2.3-4.4) Cutland C et al Emerg Infect Dis; 2015: 21: 638-645
  18. 18. Sample Size Calculation for an Efficacy Trial for an Invasive Disease Outcome Vaccine efficacy (lower bound 20% VE) Incidence (per 1000 births) Approximate Sample Size N (1:1) (+10%) 80% 1 44,000 1.5 29,000 2 22,000 3 14,700 4 11,000 70% 1 70,000 1.5 46,500 2 35,200 3 23,000 4 17,500 Serocorrelates of protection against disease are needed
  19. 19. Baker et al. (USA) J Infect Dis 2014 Dangor Z et al. (South Africa) Vaccine 2015 Serotype Ia: 90% reduced risk if ≥5 ≥3 µg/mL. Serotype III: 90% reduction in risk . Serotype Ia: 89% reduced risk if ≥0.5 µg/mL. Serotype III: 91% reduced in risk if ≥0.5 µg/mL. Need for Standardized Immunology Assays to Establish Correlate of Protection Against Invasive GBS disease.
  20. 20. stakeholders Steering group Technical advisory group Shabir Madhi (co-PI) Beate Kampmann (co-PI) Paul Heath (co-PI) David Goldblatt - UCL Moon Nahm - Birmingham Freya Williams - FDA Fatme Mawas - NIBSC Carol Baker - Baylor Luke Williams – PHE IAG Ivana Knezevic - WHO WHO PATH BioVac Industry BMGF Kirsty Le Doare (PI) Andy Gorringe (co-PI) Gaurav Kwatra (co-PI) = collaborators
  21. 21. Paper 1: Group B Streptococcal disease worldwide for pregnant women, stillbirths and children: why, what and how to undertake estimates? Paper 11: Estimates of the burden of Group B Streptococcal disease worldwide for pregnant women, stillbirths and children Lawn JE, et al Clinical Infectious Diseases. 2017;65(S2):S89-99 Overview of papers in CID – open access and launched 2. Maternal colonisation with Group B Streptococcus and serotype distribution worldwide 3. Maternal disease with Group B Streptococcus and serotype distribution worldwide 4. Stillbirth with Group B Streptococcus disease worldwide 5. Preterm birth associated with Group B Streptococcus maternal colonisation worldwide 6. Intrapartum antibiotic chemoprophylaxis policies for prevention of Group B Streptococcal Disease worldwide 7. Risk of early-onset neonatal Group B Streptococcus disease with maternal colonisation worldwide 8. Infant Group B Streptococcal disease incidence and serotypes worldwide 9. Neonatal encephalopathy with Group B Streptococcus disease worldwide 10. Neurodevelopmental impairment in children after Group B Streptococcus disease worldwide
  22. 22. 1st International Symposium on Streptococcus agalactiae Disease (ISSAD) Cape Town, South Africa Dates: 20th -23rd February 2018