Safety, tolerability, and immunogenicity of the Ebola Sudan chimpanzee adenovirus vector vaccine (cAd3-EBO S) in healthy Ugandan adults: a phase 1, open-label, dose-escalation clinical trial.

BACKGROUND: Sudan Ebola virus can cause severe viral disease, with an average case fatality rate of 54%. A recent outbreak of Sudan Ebola virus in Uganda caused 55 deaths among 164 confirmed cases in the second half of 2022. Although vaccines and therapeutics specific for Zaire Ebola virus have been approved for use during outbreak situations, Sudan Ebola virus is an antigenically distinct virus with no approved vaccines available. METHODS: In this phase 1, open-label, dose-escalation trial we evaluated the safety, tolerability, and immunogenicity of a monovalent chimpanzee adenovirus 3 vaccine against Sudan Ebola virus (cAd3-EBO S) at Makerere University Walter Reed Project in Kampala, Uganda. Study participants were recruited from the Kampala metropolitan area using International Review Board-approved written and electronic media explaining the trial intervention. Healthy adults without previous receipt of Ebola, Marburg, or cAd3 vectored-vaccines were enrolled to receive cAd3-EBO S at either 1 × 1010 or 1 × 1011 particle units (PU) in a single intramuscular vaccination and were followed up for 48 weeks. Primary safety and tolerability endpoints were assessed in all vaccine recipients by reactogenicity for the first 7 days, adverse events for the first 28 days, and serious adverse events throughout the study. Secondary immunogenicity endpoints included evaluation of binding antibody and T-cell responses against the Sudan Ebola virus glycoprotein, and neutralising antibody responses against the cAd3 vector at 4 weeks after vaccination. This study is registered with ClinicalTrials.gov, NCT04041570, and is completed. FINDINGS: 40 healthy adults were enrolled between July 22 and Oct 1, 2019, with 20 receiving 1 × 1010 PU and 20 receiving 1 × 1011 PU of cAd3-EBO S. 38 (95%) participants completed all follow-up visits. The cAd3-EBO S vaccine was well tolerated with no severe adverse events. The most common reactogenicity symptoms were pain or tenderness at the injection site (34 [85%] of 40), fatigue (29 [73%] of 40), and headache (26 [65%] of 40), and were mild to moderate in severity. Positive responses for glycoprotein-specific binding antibodies were induced by 2 weeks in 31 (78%) participants, increased to 34 (85%) participants by 4 weeks, and persisted to 48 weeks in 31 (82%) participants. Most participants developed glycoprotein-specific T-cell responses (20 [59%, 95% CI 41-75] of 34; six participants were removed from the T cell analysis after failing quality control parameters) by 4 weeks after vaccination, and neutralising titres against the cAd3 vector were also increased from baseline (90% inhibitory concentration of 47, 95% CI 30-73) to 4 weeks after vaccination (196, 125-308). INTERPRETATION: The cAd3-EBO S vaccine was safe at both doses, rapidly inducing immune responses in most participants after a single injection. The rapid onset and durability of the vaccine-induced antibodies make this vaccine a strong candidate for emergency deployment in Sudan Ebola virus outbreaks. FUNDING: National Institutes of Health via interagency agreement with Walter Reed Army Institute of Research.

Predictors of All-Cause Mortality Among People With Human Immunodeficiency Virus (HIV) in a Prospective Cohort Study in East Africa and Nigeria.

BACKGROUND: Introduction of antiretroviral therapy (ART) has been associated with a decline in human immunodeficiency virus (HIV)-related mortality, although HIV remains a leading cause of death in sub-Saharan Africa. We describe all-cause mortality and its predictors in people living with HIV (PLWH) in the African Cohort Study (AFRICOS). METHODS: AFRICOS enrolls participants with or without HIV at 12 sites in Kenya, Uganda, Tanzania, and Nigeria. Evaluations every 6 months include sociobehavioral questionnaires, medical history, physical examination, and laboratory tests. Mortality data are collected from medical records and survivor interviews. Multivariable Cox proportional hazards models were used to calculate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for factors associated with mortality. RESULTS: From 2013 through 2020, 2724 PLWH completed at least 1 follow-up visit or experienced death. Of these 58.4% were females, 25.8% were aged ≥ 50 years, and 98.3% were ART-experienced. We observed 11.42 deaths per 1000 person-years (95% CI: 9.53-13.68) with causes ascertained in 54% of participants. Deaths were caused by malignancy (28.1%), infections (29.7%), and other non-HIV related conditions. Predictors of mortality included CD4 ≤ 350 cells/µL (aHR 2.01 [95% CI: 1.31-3.08]), a log10copies/mL increase of viral load (aHR 1.36 [95% CI: 1.22-1.51]), recent fever (aHR 1.85[95% CI: 1.22-2.81]), body mass index < 18.5 kg/m2 (aHR 2.20 [95% CI: 1.44-3.38]), clinical depression (aHR 2.42 [95% CI: 1.40-4.18]), World Health Organization (WHO) stage III (aHR 2.18 [95% CI: 1.31-3.61]), a g/dL increase in hemoglobin (aHR 0.79 [95% CI: .72-.85]), and every year on ART (aHR 0.67 [95% CI: .56-.81]). CONCLUSIONS: The mortality rate was low in this cohort of mostly virally suppressed PLWH. Patterns of deaths and identified predictors suggest multiple targets for interventions to reduce mortality.