Immunogenicity and Safety of Fractional Doses of Yellow
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medRxiv preprint doi: https://doi.org/10.1101/2020.08.18.20177527; this version posted August 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 1 Immunogenicity and safety of fractional doses of yellow fever vaccines: a randomized, 2 double-blind, non-inferiority trial 3 4 Aitana Juan-Giner1,*, Derick Kimathi2,3*, Kyra H. Grantz4,5,6, Mainga M. Hamaluba2, Patrick 5 Kazooba7, Patricia Njuguna2, Gamou Fall8, Moussa Dia8, Ndeye S. Bob8, Thomas P. 6 Monath9, Alan D. Barrett10, Joachim Hombach11, Edgar M. Mulogo12, Immaculate Ampeire13, 2 7 7 4,5 7 Henry K. Karanja , Dan Nyehangane , Juliet Mwanga-Amumpaire , Derek A.T. Cummings , 8 Philip Bejon2,3, George M. Warimwe2,3,#, Rebecca F. Grais1,#. 9 10 1 Epicentre, Paris, France 11 2 Kenya Medical Research Institute – Wellcome Trust Research Programme, Kilifi, Kenya 12 3 Centre for Tropical Medicine & Global Health, University of Oxford, UK 13 4 Department of Biology, University of Florida 14 5 Emerging Pathogens Institute, University of Florida 15 6 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health 16 7 Epicentre Mbarara Research Centre, Uganda 17 8 Institut Pasteur Dakar, Senegal 18 9 Crozet BioPharma LLC, Devens MA, USA 19 10 Sealy Institute for Vaccines Sciences and Department of Pathology, University of Texas 20 Medical Branch, USA 21 11 Immunization, Vaccines & Biologicals, World Health Organization, Geneva, Switzerland 22 12 Department of Community Health, Mbarara University of Science & Technology, Uganda 23 13 Expanded Program on Immunization, Ministry of Health, Uganda 24 25 *Co-first author; #Co-senior author 26 27 Corresponding author: Rebecca F Grais; Address: 34 Avenue Jean Jaurès, 75019 Paris, 28 France; Tel: +33 (0) 1 40 21 54 75; Email: [email protected] 29 30 Word Count: 3,571 31 1 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.08.18.20177527; this version posted August 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 32 Abstract 33 Background 34 Yellow fever vaccine stocks have been insufficient to cover exceptional demands for outbreak 35 response. Fractional dosing evidence is limited to the 17DD substrain vaccine. We assessed 36 the immunogenicity and safety of one-fifth fractional dose compared to standard dose of each 37 of the four WHO-prequalified yellow fever vaccines produced from three substrains. 38 Methods 39 We conducted a randomized, double-blind, non-inferiority trial in Mbarara, Uganda and 40 Kilifi, Kenya. 960 participants aged 18-59 years without previous yellow fever vaccination or 41 infection were recruited from communities and randomized to receive one of four vaccines 42 and to standard or fractional dosage. Vaccine was administered subcutaneously by unblinded 43 nurse. Other study personnel and participants were blinded to vaccine allocation. Primary 44 immunogenicity outcome, seroconversion, was measured in the per-protocol population; 45 safety outcomes included all vaccinated participants. We defined non-inferiority as no more 46 than 10% decrease in seroconversion in fractional compared to standard dose arms 28 days 47 post-vaccination. Seroconversion was defined as ≥4-fold rise in neutralizing antibody titers 48 measured by 50% plaque reduction neutralization test (PRNT50). 49 ClinicalTrials.gov Identifier: NCT02991495, following participants. 50 Findings 51 Between 6th November 2017 and 21st February 2018, 960 participants, total sample goal, were 52 randomized. The primary per-protocol analysis includes 899 participants, with 110 to 117 53 participants per arm. The absolute difference in seroconversion between fractional and 54 standard doses by vaccine was 1.71% (95%CI: -2.60, 5.28), -0.90% (95%CI: -4.24, 3.13), 55 1.82% (95%CI: -2.75, 5.39), 0.0% (95%CI: -3.32, 3.29). Fractional doses from all four 56 vaccines met the non-inferiority criterion. There were no safety concerns. 57 Interpretation 58 These results support fractional dosing of all WHO-prequalified yellow fever vaccines for the 59 general adult population for outbreak response in situations of vaccine shortage. 60 Funding 61 The study was funded by Médecins Sans Frontières Foundation, Wellcome Trust (grant no. 62 092654) and the UK Department for International Development. Vaccines were donated in 63 kind. 2 medRxiv preprint doi: https://doi.org/10.1101/2020.08.18.20177527; this version posted August 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 64 Research in context 65 Evidence before this study 66 In July 2016, following major yellow fever (YF) outbreaks in two countries, WHO published 67 a secretariat information paper including a review of studies assessing the immunogenicity of 68 fractional doses of YF vaccines and recommended consideration of fractional doses to 69 manage a vaccine shortage. Following this, fractional doses of YF vaccine produced by Bio- 70 Manguinhos/Fiocruz (17DD substrain) were given to approximately 7.5 million non-pregnant 71 adults and children ≥2 years of age in Kinshasa, Democratic Republic of Congo. The 72 evidence base to support this action was limited to a single vaccine substrain and to a specific 73 context. To broaden and simplify recommendations, WHO called for additional research to be 74 conducted. We designed a trial to assess non-inferiority in seroconversion of fractional (one- 75 fifth dose) versus standard dose for each of the four WHO-prequalified YF vaccines at 28 76 days post-vaccination in an adult population in Kenya and Uganda. We selected vaccine 77 batches as close as possible to each manufacturer’s minimum release specification. 78 Added value of this study 79 This is the first randomized controlled trial assessing all four WHO-prequalified YF vaccines, 80 providing information on the immunogenicity and safety of fractional doses of the different 81 vaccine substrains at 10 days, 28 days and one year post-vaccination. The results show that, at 82 28 days post-vaccination, most participants had high levels of neutralizing antibodies and that 83 seroconversion rates in the fractional dose arms were non-inferior to standard dose for each of 84 the four vaccines. Seroconversion rates and neutralizing antibodies remained high up to one 85 year post-vaccination for both fractional and standard doses for all vaccines. These results are 86 aligned with previous studies using the 17DD substrain vaccine but extend the evidence to 87 randomized comparisons of all four vaccines and to a sub-Saharan Africa context. To our 88 knowledge, this is the first trial assessing immunogenicity of fractional doses at 10 days post- 89 vaccination. 90 Implications of all the available evidence 91 Our study supports the use of one-fifth fractional doses of all four WHO-prequalified yellow 92 fever vaccines for the general adult population and fills a critical knowledge gap to support 93 WHO policy on the use of fractional dosing of yellow fever vaccine for outbreak response. 94 The immunogenicity and safety of fractional dosing in children and specific populations, such 95 as those living with HIV, is yet to be determined. Long-term studies are warranted to confirm 96 the duration of protection. 3 medRxiv preprint doi: https://doi.org/10.1101/2020.08.18.20177527; this version posted August 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . 97 Introduction 98 Yellow fever is a mosquito-borne viral disease endemic in 44 countries with periodic 99 outbreaks (1). Four live attenuated yellow fever virus vaccines (derived from 17D-204, 17D- 100 213 and 17DD substrains) are World Health Organization (WHO)-prequalified (Bio- 101 Manguinhos/Fiocruz (Brazil), Federal State Unitary Enterprise of Chumakov Institut of 102 Poliomyelitis and Viral Encephalitides (Russia), Institut Pasteur de Dakar (Senegal), and 103 Sanofi Pasteur (France)). All have been widely used and are considered safe and effective (1). 104 WHO recommends routine vaccination in all countries where the disease is endemic, 105 vaccination of travelers to those areas, and mass vaccination for prevention or control of 106 outbreaks. A stockpile of 2 million doses was reserved for outbreak response in 2000 and 107 increased to 6 million in 2014 to facilitate response to major multi-country, but unpredictable 108 outbreaks (2). 109 110 An outbreak of yellow fever in 2016 in Angola raised major concerns about the adequacy of 111 vaccine supply. Routine vaccination was suspended in some African countries to meet 112 demand during the Angola outbreak (3) and a subsequent outbreak in Democratic Republic of 113 Congo (DRC) further contributed to a global shortage (4). In response, WHO reviewed the 114 evidence on fractional dosing of yellow fever vaccine as a dose-sparing option and 115 exceptionally recommended considering off-label use of fractional doses, administered by the 116 standard subcutaneous or intramuscular route, to extend supply in response to ongoing 117 outbreaks (4,5). Fractional doses (defined as one-fifth of the standard dose) of the yellow 118 fever vaccine produced by Bio-Manguinhos/Fiocruz (17DD substrain) were given to 119 approximately 7.5 million non-pregnant adults and children ≥2 years of age in Kinshasa, DRC 120 in August, 2016 (6).