Browsing by Author "Mbaya, Nelson"

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    Effect of safe water delivery plus water and sanitation hygiene behavior change communication on diarrheal disease prevalence among children under 5 years in a slum setting in Nairobi, Kenya: a quasi-experimental study
    (Springer Nature, 2025-10-28) Izudi, Jonathan; Muchiri, Evans; Musyoka, Dennis; Simiyu, Sheillah; Tumwebaze, Innocent K.; Mbaya, Nelson; Sidze, Estelle; Musau, Kelvin; Abajobir, Amanuel
    Background Diarrheal diseases are prevalent among children under five years of age in slum areas. We evaluated the effect of safe water delivery plus water, sanitation, and hygiene (WASH)-Behavior Change Communication (WASH-BCC on diarrheal disease prevalence among children under 5 years in a slum setting in Nairobi, Kenya. Methods We designed a quasi-experimental study, with the intervention as safe water delivery plus WASH-BCC. The intervention arm consisted of 2 slum villages that received safe water plus WASH-BCC, while the comparison arm comprised 2 slum villages that did not receive the intervention. The primary outcome was diarrheal disease in a child under five years of age in the past 2 weeks in both study arms, defined as the passage of ≥ 3 watery stools in the past 24 h. Data were collected at the baseline and endline from a random sample of eligible households in the villages. Propensity score weighting was used to achieve similarity in measured covariates between both arms. Binary logistic regression analysis, adjusting for propensity-score weights, was utilized to estimate the causal effect of the intervention, reported as odds ratio (OR) and 95% confidence interval (CI). Results We analyzed data from 1,876 participants in a 1:1 ratio and found 382 (20.4%) children under five years of age had diarrheal disease at the endline. Diarrheal disease prevalence declined in the intervention villages (33.3% baseline vs. 23.5% endline) but increased in the comparison villages (15.7% baseline vs. 17.5% endline). We found a 31% decline in diarrheal disease in the intervention villages relative to the comparison villages (OR 0.69, 95% CI 0.55–0.86). In a difference-in-differences analysis, the decline was 11.4%. The findings remained robust in a sensitivity analysis. Conclusion The intervention significantly reduced diarrheal disease prevalence in children under five years of age in the slum setting. Therefore, there is a need to expand the intervention to the remaining areas to reduce diarrheal disease morbidity and mortality.
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    Timeliness of vaccine administration among children in urban informal settlements in Nairobi, Kenya
    (PLOS, 2026-02-11) Ng’oda, Maurine; Izudi, Jonathan; Omenda, Collins; Njeri, Anne; Mbaya, Nelson; Ziraba, Abdhalah
    Timeliness of vaccination among children in urban informal settlements is understudied in sub-Saharan Africa. We determined the proportion of children below 5 years who received vaccines on time and the associated factors in two large urban informal settlements in Nairobi, Kenya. We conducted an analytic cross-sectional study in Viwandani and Korogocho, randomly selected households with a child below 5 years, and administered questionnaires to mothers/caregivers. Timely vaccination was defined according to the Kenya Expanded Programme on Immunization schedule. Vaccination was considered timely if administered within 28 days of birth for Bacille Calmette-Guérin (BCG), between 14 and 18 weeks for Diphtheria-Tetanus-Pertussis-Haemophilus influenzae type b-Hepatitis B dose 3 (DTP-Hib-HepB-3), and between 9 and 10 months for Measles-Containing Vaccine dose 1 (MCV1). Multivariable modified Poisson regression identified the factors associated with timely vaccination. Of 412 children, 216 (52%) with verifiable immunization booklets were analyzed for timeliness. Timely vaccination rates were 90.4% for BCG (189/209), 90.2% for DTP-HIB-Hep-3 (184/204), and 84.2% for MCV1 (160/190). Factors associated with timely vaccination included caregiver uncertainty about access to health services, which reduced the likelihood of timely BCG (adjusted prevalence risk ratio [aPR] 0.87, 95% confidence interval [CI] 0.78-0.96), DTP-Hib-HepB-3 (aPR 0.88, 95% CI 0.79-0.98), and MCV1 (aPR 0.81, 95% CI 0.70-0.94). Compared with Korogocho, children in Viwandani were more likely to receive timely MCV1 (aPR 1.18, 95% CI 1.03-1.35), whereas children of Christian caregivers were less likely than those of non-religious caregivers (aPR 0.83, 95% CI 0.70-0.99). Overall, vaccination timeliness varied by antigen, with a slight decline over time for later-schedule vaccines such as MCV1. Residence, religion, and access to routine health services were key determinants of timely vaccination. Strengthening outreach, faith-based engagement, and reminder systems in informal settlements like Korogocho could enhance vaccine timeliness, particularly for vaccines administered later in infancy.