Publications by authors named "Collins Odhiambo"

Background: Climate change increasingly impacts health, particularly of rural populations in sub-Saharan Africa due to their limited resources for adaptation. Understanding these impacts remains a challenge, as continuous monitoring of vital signs in such populations is limited. Wearable devices (wearables) present a viable approach to studying these impacts on human health in real time.

View Article and Find Full Text PDF

In this paper, performance of hurdle models in rare events data is improved by modifying their binary component. The rare-event weighted logistic regression model is adopted in place of logistic regression to deal with class imbalance due to rare events. Poisson Hurdle Rare Event Weighted Logistic Regression (REWLR) and Negative Binomial Hurdle (NBH) REWLR are developed as two-part models which use the REWLR model to estimate the probability of a positive count and a Poisson or NB zero-truncated count model to estimate non-zero counts.

View Article and Find Full Text PDF

Background: Data to inform the switch from a ritonavir-boosted protease inhibitor (PI) to dolutegravir in patients living with human immunodeficiency virus (HIV) infection who do not have genotype information and who have viral suppression with second-line therapy containing a ritonavir-boosted PI have been limited.

Methods: In a prospective, multicenter, open-label trial conducted at four sites in Kenya, we randomly assigned, in a 1:1 ratio, previously treated patients without genotype information who had viral suppression while receiving treatment containing a ritonavir-boosted PI to either switch to dolutegravir or continue the current regimen. The primary end point was a plasma HIV type 1 RNA level of at least 50 copies per milliliter at week 48, assessed on the basis of the Food and Drug Administration snapshot algorithm.

View Article and Find Full Text PDF

Since 2019, the WHO recommends the development and implementation of National Essential Diagnostics List (NEDL) to facilitate availability of In-Vitro Diagnostics (IVDs) across the various tiers of the healthcare pyramid, facilities with or without a laboratory on-site. To be effective, the development of NEDL should take into consideration the challenges and opportunities associated with current modalities for organization of tier specific testing services in-country. We conducted a mixed-methods analysis set out to explore available national policies, guidelines and decision-making processes that affect accessibility of diagnostics in African countries; 307 documents from 48 African countries were reviewed and 28 in-depth (group) interviews with 43 key-informants in seven countries were conducted between June and July 2022.

View Article and Find Full Text PDF

Background: Achievement of ISO15189 accreditation demonstrates competency of a laboratory to conduct testing. Three programmes were developed to facilitate achievement of accreditation in low- and middle-income countries: Strengthening Laboratory Management Towards Accreditation (SLMTA), Stepwise Laboratory Improvement Process Towards Accreditation (SLIPTA) and Laboratory Quality Stepwise Implementation (LQSI).

Objective: To determine the level of accreditation and associated barriers and facilitators among medical laboratories in the WHO-AFRO region by 2020.

View Article and Find Full Text PDF

Waste generated from HIV viral load (VL) testing contains potentially hazardous guanidinium thiocyanate (GTC). GTC is toxic to humans and can pollute waters and harm aquatic life if not disposed of appropriately. We assessed gaps in waste management (WM) policies, regulations and practices through a self-assessment scorecard and an online survey questionnaire among 11 African countries participating in a laboratory systems strengthening community of practice and receiving technical assistance to scale-up VL testing.

View Article and Find Full Text PDF

Background: To improve early infant HIV diagnosis (EID) programs, options include replacing laboratory-based tests with point-of-care (POC) assays or investing in strengthened systems for sample transport and result return.

Setting: We used the CEPAC-Pediatric model to examine clinical benefits and costs of 3 EID strategies in Zimbabwe for infants 6 weeks of age.

Methods: We examined (1) laboratory-based EID (LAB), (2) strengthened laboratory-based EID (S-LAB), and (3) POC EID (POC).

View Article and Find Full Text PDF

Background: Although the World Health Organization recommends HIV-exposed infants receive a 6-week diagnostic test, few receive results by 12 weeks. Point-of-care (POC) early infant diagnosis (EID) may improve timely diagnosis and treatment. This study assesses the impact of routine POC versus laboratory-based EID on return of results by 12 weeks of age.

View Article and Find Full Text PDF

Background: Hypertension is the leading risk factor for mortality globally. African countries, including Kenya, have a high and rising prevalence of hypertension. Prehypertension is associated with an increased risk of progression to overt hypertension and a higher risk of cardiovascular disease and mortality.

View Article and Find Full Text PDF

Introduction: We determine the level of adherence to the revised Kenya early infant diagnosis (EID) algorithm during implementation of a point-of-care (POC) EID project.

Methods: Data before (August 2016 to July 2017) and after (August 2017 to July 2018) introduction of POC EID were collected retrospectively from the national EID database and registers for 33 health facilities. We assessed the number of HIV-infected infants who underwent confirmatory testing and received baseline viral load test and proportion of infants with an initial negative result who had a subsequent test.

View Article and Find Full Text PDF

Background: Herpes simplex virus type 2 (HSV-2) infections are associated with increased risk of HIV transmission. We determined HSV-2 prevalence, incidence and associated risk factors, incidence among persons with indeterminate results, and prevalence of HSV-2/HIV co-infection among young adults (18-34 years) and adolescents (16-17 years) enrolled in an HIV incidence cohort study in western Kenya.

Methods: Participants (n = 1106; 846 adults) were screened and those HIV-1 negative were enrolled and followed-up quarterly for one year.

View Article and Find Full Text PDF

Background: Pregnancy is associated with changes in hematological and biochemistry values, yet there are no African reference intervals for clinical management of pregnant women. We sought to 1) develop laboratory reference intervals during pregnancy and up to 24 weeks postpartum and 2) determine the proportion of women in a previous clinical trial who would be misclassified as having out-of-range values using reference intervals from a United States (U.S.

View Article and Find Full Text PDF

Integrated approaches provide better understanding of HIV/AIDS epidemics. We optimised a multiassay algorithm (MAA) and assessed HIV incidence, correlates of recent infections, viral diversity, plus transmission clusters among participants screened for Kisumu Incidence Cohort Study (KICoS1) (2007-2009). We performed BED-CEIA, Limiting antigen (LAg) avidity, Biorad avidity, and viral load (VL) tests on HIV-positive samples.

View Article and Find Full Text PDF

Objectives: Reproductive tract infections (RTIs), including sexually acquired, among adolescent girls is a public health concern, but few studies have measured prevalence in low-middle-income countries. The objective of this study was to examine prevalence in rural schoolgirls in Kenya against their reported symptoms.

Methods: In 2013, a survey was conducted in 542 adolescent schoolgirls aged 14-17 years who were enrolled in a menstrual feasibility study.

View Article and Find Full Text PDF

Objective: The prevalence of anaemia during pregnancy is estimated to be 35-75% in sub-Saharan Africa and is associated with an increased risk of maternal mortality. We evaluated the frequency and factors associated with anaemia in HIV-infected women undergoing antiretroviral (ARV) therapy for prevention of mother-to-child transmission (PMTCT) enrolled in The Kisumu Breastfeeding Study 2003-2009.

Methods: Maternal haematological parameters were monitored from 32 to 34 weeks of gestation to 2 years post-delivery among 522 enrolled women.

View Article and Find Full Text PDF

Background: Anemia results in increased morbidity and mortality, underscoring the need to better understand its pathophysiology amongst HIV-exposed and infected children in sub-Saharan Africa, the region where most infant HIV exposure and infections occur.

Methods: This analysis used samples obtained from children in the Kisumu Breastfeeding Study (KiBS). KiBS was a longitudinal phase IIB, open-label, one-arm clinical trial, designed to investigate the safety, tolerability and effectiveness of a maternal triple-antiretroviral (ARV) regimen for prevention of mother-to-child transmission (PMTCT) of HIV, during late pregnancy and early infancy while breastfeeding.

View Article and Find Full Text PDF

Bunyamwera and Ngari viruses have been isolated from a range of mosquito species in Kenya but their actual role in the maintenance and transmission of these viruses in nature remains unclear. Identification of the mosquito species efficient in transmitting these viruses is critical for estimating the risk of human exposure and understanding the transmission and maintenance mechanism. We determined the vector competence of, Aedes aegypti (L.

View Article and Find Full Text PDF

Ngari, Bunyamwera, Ilesha, and Germiston viruses are among the mosquito-borne human pathogens in the Orthobunyavirus genus, family Bunyaviridae, associated with febrile illness. Although the four orthobunyaviruses have been isolated from mosquito and/or tick vectors sampled from different geographic regions in Kenya, little is known of human exposure in such areas. We conducted a serologic investigation to determine whether orthobunyaviruses commonly infect humans in Kenya.

View Article and Find Full Text PDF

Background: Important differences have been demonstrated in laboratory parameters from healthy persons in different geographical regions and populations, mostly driven by a combination of genetic, demographic, nutritional, and environmental factors. Despite this, European and North American derived laboratory reference intervals are used in African countries for patient management, clinical trial eligibility, and toxicity determination; which can result in misclassification of healthy persons as having laboratory abnormalities.

Methods: An observational prospective cohort study known as the Kisumu Incidence Cohort Study (KICoS) was conducted to estimate the incidence of HIV seroconversion and identify determinants of successful recruitment and retention in preparation for an HIV vaccine/prevention trial among young adults and adolescents in western Kenya.

View Article and Find Full Text PDF

Background: West Nile virus (WNV) has a wide geographical distribution and has been associated to cause neurological disease in humans and horses. Mosquitoes are the traditional vectors for WNV; however, the virus has also been isolated from tick species in North Africa and Europe which could be a means of introduction and spread of the virus over long distances through migratory birds. Although WNV has been isolated in mosquitoes in Kenya, paucity of genetic and pathogenicity data exists.

View Article and Find Full Text PDF

Biological phenotypes of tri-segmented arboviruses display characteristics that map to mutation/s in the S, M or L segments of the genome. Plaque variants have been characterized for other viruses displaying varied phenotypes including attenuation in growth and/or pathogenesis. In order to characterize variants of Bunyamwera and Ngari viruses, we isolated individual plaque size variants; small plaque (SP) and large plaque (LP) and determined in vitro growth properties and in vivo pathogenesis in suckling mice.

View Article and Find Full Text PDF

Background: Severe anemia due to Plasmodium falciparum malaria is a major cause of mortality among young children in western Kenya. The factors that lead to the age-specific incidence of this anemia are unknown. Previous studies have shown an age-related expression of red cell complement regulatory proteins, which protect erythrocytes from autologous complement attack and destruction.

View Article and Find Full Text PDF