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Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report.

ABSTRACT: BACKGROUND:In 2016, the response to a yellow fever outbreak in Angola and the Democratic Republic of Congo led to a global shortage of yellow fever vaccine. As a result, a fractional dose of the 17DD yellow fever vaccine (containing one fifth [0.1 ml] of the standard dose) was offered to 7.6 million children 2 years of age or older and nonpregnant adults in a preemptive campaign in Kinshasa. The goal of this study was to assess the immune response to the fractional dose in a large-scale campaign. METHODS:We recruited participants in four age strata at six vaccination sites. We assessed neutralizing antibody titers against yellow fever virus in blood samples obtained before vaccination and at 1 month and 1 year after vaccination, using a plaque reduction neutralization test with a 50% cutoff (PRNT50). Participants with a PRNT50 titer of 10 or higher were considered to be seropositive. Those with a baseline titer of less than 10 who became seropositive at follow-up were classified as having undergone seroconversion. Participants who were seropositive at baseline and who had an increase in the titer by a factor of 4 or more at follow-up were classified as having an immune response. RESULTS:Among 716 participants who completed the 1-month follow-up, 705 (98%; 95% confidence interval [CI], 97 to 99) were seropositive after vaccination. Among 493 participants who were seronegative at baseline, 482 (98%; 95% CI, 96 to 99) underwent seroconversion. Among 223 participants who were seropositive at baseline, 148 (66%; 95% CI, 60 to 72) had an immune response. Lower baseline titers were associated with a higher probability of having an immune response (P<0.001). Among 684 participants who completed the 1-year follow-up, 666 (97%; 95% CI, 96 to 98) were seropositive for yellow fever antibody. The distribution of titers among the participants who were seronegative for yellow fever antibody at baseline varied significantly among age groups at 1 month and at 1 year (P<0.001 for both comparisons). CONCLUSIONS:A fractional dose of the 17DD yellow fever vaccine was effective at inducing seroconversion in participants who were seronegative at baseline. Titers remained above the threshold for seropositivity at 1 year after vaccination in nearly all participants who were seropositive at 1 month after vaccination. These findings support the use of fractional-dose vaccination for outbreak control. (Funded by the U.S. Agency for International Development and the Centers for Disease Control and Prevention.).

SUBMITTER: Casey RM

PROVIDER: S-EPMC7064153 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report.

Casey Rebecca M RM Harris Jennifer B JB Ahuka-Mundeke Steve S Dixon Meredith G MG Kizito Gabriel M GM Nsele Pierre M PM Umutesi Grace G Laven Janeen J Kosoy Olga O Paluku Gilson G Gueye Abdou S AS Hyde Terri B TB Ewetola Raimi R Sheria Guylain K M GKM Muyembe-Tamfum Jean-Jacques JJ Staples J Erin JE

The New England journal of medicine 20180214 5

<h4>Background</h4>In 2016, the response to a yellow fever outbreak in Angola and the Democratic Republic of Congo led to a global shortage of yellow fever vaccine. As a result, a fractional dose of the 17DD yellow fever vaccine (containing one fifth [0.1 ml] of the standard dose) was offered to 7.6 million children 2 years of age or older and nonpregnant adults in a preemptive campaign in Kinshasa. The goal of this study was to assess the immune response to the fractional dose in a large-scale ...[more]

PMID: 29443626

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Project description:BackgroundStocks of yellow fever vaccine are insufficient to cover exceptional demands for outbreak response. Fractional dosing has shown efficacy, but evidence is limited to the 17DD substrain vaccine. We assessed the immunogenicity and safety of one-fifth fractional dose compared with standard dose of four WHO-prequalified yellow fever vaccines produced from three substrains.MethodsWe did this randomised, double-blind, non-inferiority trial at research centres in Mbarara, Uganda, and Kilifi, Kenya. Eligible participants were aged 18-59 years, had no contraindications for vaccination, were not pregnant or lactating, had no history of yellow fever vaccination or infection, and did not require yellow fever vaccination for travel. Eligible participants were recruited from communities and randomly assigned to one of eight groups, corresponding to the four vaccines at standard or fractional dose. The vaccine was administered subcutaneously by nurses who were not masked to treatment, but participants and other study personnel were masked to vaccine allocation. The primary outcome was proportion of participants with seroconversion 28 days after vaccination. Seroconversion was defined as post-vaccination neutralising antibody titres at least 4 times pre-vaccination measurement measured by 50% plaque reduction neutralisation test (PRNT50). We defined non-inferiority as less than 10% decrease in seroconversion in fractional compared with standard dose groups 28 days after vaccination. The primary outcome was measured in the per-protocol population, and safety analyses included all vaccinated participants. This trial is registered with ClinicalTrials.gov, NCT02991495.FindingsBetween Nov 6, 2017, and Feb 21, 2018, 1029 participants were assessed for inclusion. 69 people were ineligible, and 960 participants were enrolled and randomly assigned to vaccine manufacturer and dose (120 to Bio-Manguinhos-Fiocruz standard dose, 120 to Bio-Manguinhos-Fiocruz fractional dose, 120 to Chumakov Institute of Poliomyelitis and Viral Encephalitides standard dose, 120 to Chumakov Institute of Poliomyelitis and Viral Encephalitides fractional dose, 120 to Institut Pasteur Dakar standard dose, 120 to Institut Pasteur Dakar fractional dose, 120 to Sanofi Pasteur standard dose, and 120 to Sanofi Pasteur fractional dose). 49 participants had detectable PRNT50 at baseline and 11 had missing PRNT50 results at baseline or 28 days. 900 were included in the per-protocol analysis. 959 participants were included in the safety analysis. The absolute difference in seroconversion between fractional and standard doses by vaccine was 1·71% (95% CI -2·60 to 5·28) for Bio-Manguinhos-Fiocruz, -0·90% (-4·24 to 3·13) for Chumakov Institute of Poliomyelitis and Viral Encephalitides, 1·82% (-2·75 to 5·39) for Institut Pasteur Dakar, and 0·0% (-3·32 to 3·29) for Sanofi Pasteur. Fractional doses from all four vaccines met the non-inferiority criterion. The most common treatment-related adverse events were headache (22·2%), fatigue (13·7%), myalgia (13·3%) and self-reported fever (9·0%). There were no study-vaccine related serious adverse events.InterpretationFractional doses of all WHO-prequalified yellow fever vaccines were non-inferior to the standard dose in inducing seroconversion 28 days after vaccination, with no major safety concerns. These results support the use of fractional dosage in the general adult population for outbreak response in situations of vaccine shortage.FundingThe study was funded by Médecins Sans Frontières Foundation, Wellcome Trust (grant no. 092654), and the UK Department for International Development. Vaccines were donated in kind.

Project description:BackgroundIntradermal administration of fractional inactivated poliovirus vaccine (fIPV) is a dose-sparing alternative to the intramuscular full dose. We aimed to compare the immunogenicity of two fIPV doses versus one IPV dose for routine immunisation, and also assessed the immunogenicity of an fIPV booster dose for an outbreak response.MethodsWe did an open-label, randomised, controlled, inequality, non-inferiority trial in two clinics in Dhaka, Bangladesh. Healthy infants were randomly assigned at 6 weeks to one of four groups: group A received IPV at age 14 weeks and IPV booster at age 22 weeks; group B received IPV at age 14 weeks and fIPV booster at age 22 weeks; group C received IPV at age 6 weeks and fIPV booster at age 22 weeks; and group D received fIPV at 6 weeks and 14 weeks and fIPV booster at age 22 weeks. IPV was administered by needle-syringe as an intramuscular full dose (0·5 mL), and fIPV was administered intradermally (0·1 mL of the IPV formulation was administered using the 0·1 mL HelmJect auto-disable syringe with a Helms intradermal adapter). Both IPV and fIPV were administered on the outer, upper right thigh of infants. The primary outcome was vaccine response to poliovirus types 1, 2, and 3 at age 22 weeks (routine immunisation) and age 26 weeks (outbreak response). Vaccine response was defined as seroconversion from seronegative (<1:8) at baseline to seropositive (≥1:8) or four-fold increase in reciprocal antibody titres adjusted for maternal antibody decay and was assessed in the modified intention-to-treat population (infants who received polio vaccines per group assignment and polio antibody titre results to serotypes 1, 2, and 3 at 6, 22, 23, and 26 weeks of age). The non-inferiority margin was 12·5%. This trial is registered with ClinicalTrials.gov, number NCT02847026.FindingsBetween Sept 1, 2016 and May 2, 2017, 1076 participants were randomly assigned and included in the modified intention-to-treat analysis: 271 in Group A, 267 in group B, 268 in group C, and 270 in group D. Vaccine response at 22 weeks to two doses of fIPV (group D) was significantly higher (p<0·0001) than to one dose of IPV (groups A and B) for all three poliovirus serotypes: the type 1 response comprised 212 (79% [95% CI 73-83]) versus 305 (57% [53-61]) participants, the type 2 response comprised 173 (64% [58-70]) versus 249 (46% [42-51]) participants, and the type 3 response comprised 196 (73% [67-78]) versus 196 (36% [33-41]) participants. At 26 weeks, the fIPV booster was non-inferior to IPV (group B vs group A) for serotype 1 (-1·12% [90% CI -2·18 to -0·06]), serotype 2 (0·40%, [-2·22 to 1·42]), and serotype 3 (1·51% [-3·23 to -0·21]). Of 129 adverse events, 21 were classified as serious including one death; none were attributed to IPV or fIPV.InterpretationfIPV appears to be an effective dose-sparing strategy for routine immunisation and outbreak responses.FundingUS Centers for Disease Control and Prevention.

Dataset Information

Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report.

Publications

Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report.

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