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Genetic epidemiology of dengue viruses in phase III trials of the CYD tetravalent dengue vaccine and implications for efficacy.

ABSTRACT: This study defined the genetic epidemiology of dengue viruses (DENV) in two pivotal phase III trials of the tetravalent dengue vaccine, CYD-TDV, and thereby enabled virus genotype-specific estimates of vaccine efficacy (VE). Envelope gene sequences (n = 661) from 11 DENV genotypes in 10 endemic countries provided a contemporaneous global snapshot of DENV population genetics and revealed high amino acid identity between the E genes of vaccine strains and wild-type viruses from trial participants, including at epitope sites targeted by virus neutralising human monoclonal antibodies. Post-hoc analysis of all CYD14/15 trial participants revealed a statistically significant genotype-level VE association within DENV-4, where efficacy was lowest against genotype I. In subgroup analysis of trial participants age 9-16 years, VE estimates appeared more balanced within each serotype, suggesting that genotype-level heterogeneity may be limited in older children. Post-licensure surveillance is needed to monitor vaccine performance against the backdrop of DENV sequence diversity and evolution.

SUBMITTER: Rabaa MA

PROVIDER: S-EPMC5584992 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Genetic epidemiology of dengue viruses in phase III trials of the CYD tetravalent dengue vaccine and implications for efficacy.

Rabaa Maia A MA Girerd-Chambaz Yves Y Duong Thi Hue Kien K Vu Tuan Trung T Wills Bridget B Bonaparte Matthew M van der Vliet Diane D Langevin Edith E Cortes Margarita M Zambrano Betzana B Dunod Corinne C Wartel-Tram Anh A Jackson Nicholas N Simmons Cameron P CP

eLife 20170905

This study defined the genetic epidemiology of dengue viruses (DENV) in two pivotal phase III trials of the tetravalent dengue vaccine, CYD-TDV, and thereby enabled virus genotype-specific estimates of vaccine efficacy (VE). Envelope gene sequences (n = 661) from 11 DENV genotypes in 10 endemic countries provided a contemporaneous global snapshot of DENV population genetics and revealed high amino acid identity between the E genes of vaccine strains and wild-type viruses from trial participants, ...[more]

PMID: 28871961

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Project description:BackgroundDengue hemorrhagic fever is the leading cause of hospitalization and death in children living in Asia and Latin America. There is an urgent need for an effective and safe dengue vaccine to reduce morbidity and mortality in this high-risk population given the lack of dengue specific treatment at present. This review aims to determine the efficacy, safety, and immunogenicity of CYD-TDV vaccine in children.MethodsThis is a systematic review including meta-analysis of randomized controlled clinical trial data from Embase, Medline, the Cochrane Library, Web of Science, and ClinicalTrials.gov. Studies that assessed CYD-TDV vaccine efficacy [(1?-?RR)*100], safety (RR), and immunogenicity (weighted mean difference) in children were included in this study. Random effects model was employed to analyze patient-level data extracted from primary studies.ResultsThe overall efficacy of CYD-TDV vaccine was 54% (40-64), while serotype-specific efficacy was 77% (66-85) for DENV4, 75% (65-82) for DENV3, 50% (36-61) for DENV1, and 34% (14-49) for DENV2. 15% (-174-74) vaccine efficacy was obtained for the unknown serotype. Meta-analysis of included studies with longer follow-up time (25?months) revealed that CYD-TDV vaccine significantly increased the risk of injection site reactions (RR?=?1.1: 1.04-1.17; p-value?=?0.001). Immunogenicity (expressed as geometric mean titers) in descending order was 439.7 (331.7-547.7), 323 (247 - 398.7), 144.1 (117.9-170.2), and 105 (88.7-122.8) for DENV3, DENV2, DENV1, and DENV4, respectively.ConclusionCYD-TDV vaccine is effective and immunogenic in children overall. Reduced efficacy of CYD-TDV vaccine against DENV2 notoriously known for causing severe dengue infection and dengue outbreaks cause for serious concern. Post hoc meta-analysis of long-term follow-up data (?25?months) from children previously vaccinated with CYD-TDV vaccine is needed to make a conclusion regarding CYD-TDV vaccine safety in children. However, CYD-TDV vaccine should be considered for use in regions where DENV2 is not endemic as currently there is no specific treatment for dengue infection.

Project description:BackgroundRandomised controlled trials have evaluated the recombinant tetravalent dengue vaccine (CYD-TDV). However, individual results may have little power to identify differences among the populations studied.ObjectiveTo evaluate efficacy, immunogenicity and safety of CYD-TDV in the prevention of dengue in children aged 2-17 years.DesignSystematic review and meta-analysis.Data sourcesMEDLINE (from 1950 to 5 December 2018), EMBASE (from 1947 to 5 December 2018) and Cochrane (from 1993 to 5 December 2018).Eligibility criteria of studiesRandomised trials comparing efficacy, immunogenicity and safety of CYD-TDV with placebo or other vaccines for preventing dengue cases in children aged 2-17 years.Outcome measuresEfficacy, immunogenicity and safety of CYD-TDV.Study appraisal and methodsCalculations were made of relative risk (RR) and mean difference (MD) for dichotomous and continuous outcomes, respectively. All estimates were calculated considering a 95% CI estimate. A p<0.05 was considered statistically significant.ResultsNine studies involving 34 248 participants were included. The overall efficacy of CYD-TDV was 60% (RR 0.40 (0.30 to 0.54)). Serotype-specific efficacy of the vaccine was 51% for dengue virus type-1 (DENV-1) (RR 0.49 (0.39 to 0.63)); 34% for DENV-2 (RR 0.66 (0.50 to 0.86)); 75% for DENV-3 (RR 0.25 (0.18 to 0.35)) and 77% for DENV-4 (RR 0.23 (0.15 to 0.34)). Overall immunogenicity (MD) of CYD-TDV was 225.13 (190.34 to 259.93). Serotype-specific immunogenicity was: DENV-1: 176.59 (123.36 to 229.83); DENV-2: 294.21 (181.98 to 406.45); DENV-3: 258.78 (146.72 to 370.84) and DENV-4: 189.35 (141.11 to 237.59). The most common adverse events were headache and pain at the injection site.LimitationsThe main limitation of this study was unclear or incomplete data.Conclusions and implications of key findingsCYD-TDV is considered safe and able to partially protect children and adolescents against four serotypes of DENV for a 1-year period. Despite this, research should prioritise improvements in vaccine efficacy, thus proving higher long-term protection against all virus serotypes.Prospero registration numberCRD42016043628.

Project description:BACKGROUND:The live attenuated tetravalent dengue vaccine (CYD-TDV) is licensed using a 0-, 6- and 12-month schedule in dengue-endemic areas. An effective shorter schedule may provide more rapid, optimal protection of targeted populations during vaccine campaigns in dengue-endemic countries. We compared immune responses to two schedules of CYD-TDV in a non-endemic population. We also evaluated the impact of yellow fever (YF) co-administration. METHODS:This phase II, open-label, multicentre study enrolled 390 healthy 18-45-year-olds in the USA with no prior exposure to dengue. Participants were randomised (4:4:4:1) to four treatment groups stratified by prior YF vaccine status: Group 1, CYD-TDV standard 0-6-12 months schedule; Group 2, CYD-TDV accelerated 0-2-6 months schedule; Group 3, CYD-TDV accelerated schedule with YF co-administered (dose 1); Group 4, YF vaccination only. Neutralising antibody geometric mean titres (GMTs) and percentages of seropositive participants (antibody titres ?10 [1/dil]) were measured against each dengue serotype using a 50% plaque reduction neutralisation test. RESULTS:On D28 post-CYD-TDV dose 3, there were no marked differences in seropositivity rates and GMTs between Groups 1 and 2. In Groups 1 and 2 respectively, 73.4 and 82.4% were dengue seropositive for ?3 serotypes, with 50.0 and 42.6% seropositive against all four serotypes. Flavivirus status (FV+ or FV-) at baseline did not markedly affect GMTs and seropositivity rates with either schedule. In Groups 1 and 2, GMTs measured 6 months after the third dose decreased against all serotypes, except for a small increase in GMT for serotype 4 in Group 1. In addition, dengue seropositivity remained above 70% for serotypes 2, 3 and 4 in Groups 1 and 2. Co-administration with YF did not affect antibody responses against dengue and YF or impact vaccine safety following completion of the compressed schedule, compared to dengue or YF vaccination alone. CONCLUSIONS:The live attenuated CYD-TDV vaccine given in a compressed schedule in a non-endemic setting can elicit similar antibody responses to the licensed CYD-TDV schedule. TRIAL REGISTRATION:This trial was registered on cinicaltrials.gov, NCT01488890 (December 8, 2011).

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Genetic epidemiology of dengue viruses in phase III trials of the CYD tetravalent dengue vaccine and implications for efficacy.

Publications

Genetic epidemiology of dengue viruses in phase III trials of the CYD tetravalent dengue vaccine and implications for efficacy.

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