Skip to main content
Health & Medicine

Immunogenicity of fractional one-fifth and one-half doses of 17DD yellow fever vaccine compared with full dose in children aged 9-23 months in Uganda: a phase 4, single-blind, randomised clinical tria

| Source: Lancet (London, England)

Fractional doses of yellow fever vaccines have been shown to be safe and immunogenic in randomised controlled trials in adults and children. However, little evidence still remains in children younger than 2 years. We assessed immunogenicity of one-fifth (0·1 mL) and one-half (0·25 mL) fractional doses compared with full doses of 17DD yellow fever vaccine in children aged 9-23 months in Kampala, Uganda. This phase 4, single-blind, randomised clinical trial evaluating fractional dose 17D

Fractional doses of yellow fever vaccines have been shown to be safe and immunogenic in randomised controlled trials in adults and children. However, little evidence still remains in children younger than 2 years. We assessed immunogenicity of one-fifth (0·1 mL) and one-half (0·25 mL) fractional doses compared with full doses of 17DD yellow fever vaccine in children aged 9-23 months in Kampala, Uganda. This phase 4, single-blind, randomised clinical trial evaluating fractional dose 17DD yellow fever vaccine among children was conducted at three public-sector health facilities in Uganda. Eligible participants were aged 9-23 months at enrolment, had no history of yellow fever disease or vaccination, and did not meet the exclusion criteria. Children were enrolled in three age strata: 9-12 months, 13-18 months, and 19-23 months, and were randomly assigned (1:1:1) using block randomisation (block sizes of three and six) to one-fifth (0·1 mL), one-half (0·25 mL), or full (0·5 mL) doses of the 17DD yellow fever vaccine. Participants were followed up at 4 weeks (visit 1 [V1]), 1 year (visit 2 [V2]), and 13-48 months (visit 3 [V3]) after vaccination. The primary analysis included per-protocol participants who attended within the prespecified visit window; an intention-to-treat analysis was also conducted including all randomly assigned participants with available outcome data. Participants with missing serological data were excluded from the analysis at the corresponding visit. The primary outcome was non-inferiority in seroconversion (5 percentage-point margin) at V1 measured by 50% plaque reduction neutralisation test. This study is registered with ClinicalTrials.gov, NCT03725618, and is complete. Between March 26, 2019, and May 11, 2021, 1784 participants were randomly assigned to either one-fifth dose (n=600), one-half dose (n=594), or full dose (n=590). The median (IQR) age at enrolment was 13 (11-18) months. Both fractional doses met the non-inferiority criterion compared with the full dose with no difference in seroconversion between one-fifth and full doses and -0·17 (95% CI -0·52 to 0·17) difference between one-half and full doses in the per-protocol population at V1. There was no difference between the one-fifth and full doses. Both fractional doses of 17DD yellow fever vaccine were non-inferior to full doses in inducing initial seroconversion. The results support the use of fractional dose yellow fever vaccines among young children for outbreak response during supply shortages. US Centers for Disease Control and Prevention.

Read the original source →

Related Stories

Health & Medicine

Chronic cigarette smoke exposure induces distinct stem cell states driving genetic driver-specific non-small cell lung cancer subtypes.

Cigarette smoke-induced chronic inflammation (CI) potentiates development of non-small cell lung cancer (NSCLC) by mediating genetic and epigenetic events. Using normal lung organoids (LOs), we define how chronic cigarette smoke condensate (CSC) exposure drives two separate stem cell populations to evolve premalignant states harboring progressive epigenetic and linked transcriptomic abnormalities in the absence of major driver mutations. These dynamics facilitate evolution of an immune evasive s

Continue reading
Health & Medicine

Extended fractional Hofstadter states at high field in twisted bilayer graphene above the magic angle.

When a Chern band is partially filled, a fractional Chern insulator (FCI)-the lattice analog of a fractional quantum Hall state-can arise. Though the full range of possible scenarios for producing such a state is not established, the most tractable models combine strong electronic interactions with the quantum geometry of the parent Chern band meeting specific criteria. In twisted bilayer graphene, the importance of interactions can be tuned by varying the interlayer twist. Here, we study a samp

Continue reading
Health & Medicine

Phenotypic screening identifies kenpaullone as a prolymphangiogenic compound to improve heart repair following myocardial infarction.

Myocardial infarction (MI) induces cardiac muscle death and its subsequent replacement by a noncontractile fibrotic scar, which underlies progression to heart failure. Current treatments restore blood flow and assist with cardiac workload but do not promote regeneration. We have previously shown endogenous growth of the cardiac lymphatic system following MI and further stimulation with the lymphatic endothelial specific mutated Vascular Endothelial Growth Factor-C (VEGF-C) isoform, VEGFC-C156S,

Continue reading
Health & Medicine

Dopamine suppresses pathological retinal oscillations and enhances the signal-to-noise ratio.

Infantile nystagmus is a debilitating involuntary eye movement disorder often associated with retinal diseases such as congenital stationary night blindness (CSNB). The oscillating eye movements of infantile nystagmus come with reduced visual acuity and strongly impair quality of life. No cure exists for this condition. Previously, we demonstrated that nystagmus in the CSNB mouse model Nyx nob has a retinal cause. Specifically, we found that synchronized oscillations of retinal ganglion cells (R

Continue reading
Health & Medicine

Spatial and single-nucleus transcriptomics reveals the molecular pathology of type 2 diabetes-associated cognitive dysfunction.

The mechanisms underlying type 2 diabetes-associated cognitive dysfunction (DACD) remain poorly understood, hindering therapeutic progress. Here, we integrated spatial transcriptomics and single-nucleus RNA sequencing to delineate the spatiotemporal molecular and cellular landscape of DACD in brain tissues from 3- and 6-mo-old mouse models. Our findings revealed region- and cell-type-specific transcriptomic alterations, with excitatory neurons in the hippocampus and isocortex emerging as the mos

Continue reading