1. Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak — Final Report
- Author
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J. Erin Staples, Janeen Laven, Gabriel M Kizito, Meredith G Dixon, Steve Ahuka-Mundeke, Abdou Salam Gueye, Grace Umutesi, Pierre M Nsele, Jean-Jacques Muyembe-Tamfum, Guylain K M Sheria, Rebecca M Casey, Olga I. Kosoy, Raimi Ewetola, Terri B. Hyde, Gilson Paluku, and Jennifer B. Harris
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Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Adolescent ,Yellow fever vaccine ,Antibodies, Viral ,Article ,Disease Outbreaks ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Plaque reduction neutralization test ,Internal medicine ,Yellow Fever ,medicine ,Humans ,030212 general & internal medicine ,Seroconversion ,Child ,business.industry ,Immunogenicity ,Yellow Fever Vaccine ,Yellow fever ,Outbreak ,General Medicine ,Middle Aged ,medicine.disease ,Antibodies, Neutralizing ,Vaccination ,Titer ,030104 developmental biology ,Child, Preschool ,Democratic Republic of the Congo ,Female ,Yellow fever virus ,business ,Follow-Up Studies ,medicine.drug - 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 (PRNT(50)). Participants with a PRNT(50) 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
- Published
- 2019
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