ORCID Profile
0000-0001-5330-1470
Current Organisations
Stanford University School of Medicine
,
Infectious Diseases Research Laboratory
,
Charles River Medical Group
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Society for Microbiology
Date: 07-2017
DOI: 10.1128/JCM.00176-17
Abstract: Although Roche COBAS Ampliprep/COBAS TaqMan (CAP/CTM) systems are widely used in sub-Saharan Africa for early infant diagnosis of HIV from dried blood spots (DBS), viral load monitoring with this system is not practical due to nonspecific extraction of both cell-free and cell-associated viral nucleic acids. A simplified DBS extraction technique for cell-free virus elution using phosphate-buffered saline (PBS) may provide an alternative analyte for lower-cost quantitative HIV virus load (VL) testing to monitor antiretroviral therapy (ART). We evaluated the CAP/CTM v2.0 assay in 272 paired plasma and DBS specimens using the cell-free virus elution method and determined the level of agreement, sensitivity, and specificity at thresholds of target not detected (TND), target below the limit of quantification (BLQ) ( copies/ml in plasma or copies/ml in DBS), and VL of ,000 copies/ml, and VL of ,000 copies/ml. Reported plasma VL ranged from TND, or , to 5,781,592 copies/ml, and DBS VL ranged from TND, or , to 467,600 copies/ml. At copies/ml, agreement between DBS and plasma was 96.7% (kappa coefficient, 0.93 P 0.0001). The mean difference between DBS and plasma VL values was −1.06 log 10 copies/ml (95% confidence interval [CI], −1.17, −0.97 P 0.0001). At a treatment failure threshold of ,000 copies/ml, the sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) were 92.7%, 100%, 100%, and 94.3%, respectively. PBS elution of DBS offers a sensitive and specific method for monitoring plasma viremia among adults and children on ART at the WHO-recommended threshold of ,000 copies/ml on the Roche CAP/CTM system.
Publisher: MDPI AG
Date: 21-10-2022
Abstract: Vaccination is one of the most effective methods for preventing morbidity and mortality from COVID-19. Vaccine hesitancy has led to a decrease in vaccine uptake driven by misinformation, fear, and misperceptions of vaccine safety. Whole inactivated vaccines have been used in one-fifth of the vaccine recipients in Africa, however there are limited real-world data on their safety. We evaluated the reported adverse events and factors associated with reported adverse events following vaccination with whole inactivated COVID-19 vaccines-BBiBP-CorV (Sinopharm) and CoronaVac (Sinovac). A quantitative survey evaluating attitudes and adverse events from vaccination was administered to 1016 adults presenting at vaccination centers. Two follow-up telephone interviews were conducted to determine adverse events after the first and second vaccination dose. Overall, the vaccine was well tolerated 26.0% and 14.4% reported adverse events after the first and second dose, respectively. The most frequent local and systemic adverse events were pain at the injection site and headaches, respectively. Most symptoms were mild, and no participants required hospitalization. Participants who perceived COVID-19 vaccines as safe or had a personal COVID-19 experience were significantly less likely to report adverse events. Our findings provide data on the safety and tolerability of whole inactivated COVID-19 vaccines in an African population, providing the necessary data to create effective strategies to increase vaccination and support vaccination c aigns.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-06-2021
Publisher: Oxford University Press (OUP)
Date: 06-2010
DOI: 10.1086/652652
Abstract: BACKGROUND. Cryptococcal meningitis (CM) remains a leading cause of acquired immunodeficiency syndrome-related death in sub-Saharan Africa. The timing of the initiation of antiretroviral therapy (ART) for human immunodeficiency virus (HIV)-associated CM remains uncertain. The study aimed to determine the optimal timing for initiation of ART in HIV-positive in iduals with CM. METHODS. A prospective, open-label, randomized clinical trial was conducted at a tertiary teaching hospital in Zimbabwe. Participants were aged > or = 18 years, were ART naive, had received a first CM diagnosis, and were randomized to receive early ART (within 72 h after CM diagnosis) or delayed ART (after 10 weeks of treatment with fluconazole alone). Participants received 800 mg of fluconazole per day. The ART regimen used was stavudine, lamivudine, and nevirapine given twice daily. The duration of follow-up was up to 3 years. The primary end point was all-cause mortality. RESULTS. Fifty-four participants were enrolled in the study (28 in the early ART arm and 26 in the delayed ART arm). The median CD4 cell count at enrollment was 37 cells/mm(3) (interquartile range, 17-69 cells/mm(3)). The 3-year mortality rate differed significantly between the early and delayed ART groups (88% vs 54% P < .006) the overall 3-year mortality rate was 73%. The median durations of survival were 28 days and 637 days in the early and delayed ART groups, respectively (P = .031, by log-rank test). The risk of mortality was almost 3 times as great in the early ART group versus the delayed ART group (adjusted hazard ratio, 2.85 95% confidence interval, 1.1-7.23). The study was terminated early by the data safety monitoring committee. CONCLUSIONS. In resource-limited settings where CM management may be suboptimal, when compared with a delay of 10 weeks after a CM diagnosis, early initiation of ART results in increased mortality. Trial registration. ClinicalTrials.gov identifier: NCT00830856.
Publisher: Public Library of Science (PLoS)
Date: 07-07-2016
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2019
Publisher: Elsevier BV
Date: 06-2015
Publisher: MDPI AG
Date: 02-09-2022
DOI: 10.20944/PREPRINTS202209.0033.V1
Abstract: Vaccination is one of the most effective methods for preventing morbidity and mortality from COVID-19. Vaccine hesitancy has led to a decrease in vaccine uptake driven by misinformation, fear, and perceptions of vaccine safety. Whole inactivated vaccines have been used in one-fifth of the vaccine recipients in Africa, however there is limited real-world data on their safety. We evaluated the reported side effects and factors associated with reported side effects following vaccination with whole inactivated COVID-19 vaccines - BBiBP-CorV (Sinopharm) and CoronaVac (Sinovac). A quantitative survey evaluating attitudes and side effects from vaccination was administered to 1016 adults presenting at vaccination centers. Two follow-up telephone interviews were conducted to determine side effects after the first and second vaccination dose. Overall, the vaccine was well tolerated 26.0% and 14.4% reported side effects after the first and second dose respectively. The most frequent local and systemic side effects were pain at the injection site and headaches respectively. Most symptoms were mild, and no participants re-quired hospitalization. Participants who perceived COVID-19 vaccines as safe or had a personal COVID-19 experience were significantly less likely to report side effects. Our findings provide data on the safety and tolerability of whole inactivated COVID-19 vaccines in an African population, providing the necessary data to create effective strategies to increase vaccination and support vaccination c aigns.
Publisher: American Society for Microbiology
Date: 24-08-2020
DOI: 10.1128/JCM.01045-20
Abstract: HIV drug resistance (HIVDR) is a barrier to sustained virologic suppression in low- and middle-income countries (LMICs). Point mutation assays targeting priority drug resistance mutations (DRMs) are being evaluated to improve access to HIVDR testing. In a cross-sectional study (June 2018 to September 2019), we evaluated the diagnostic accuracy of a simple and rapid HIVDR assay (the pan-degenerate lification and adaptation [PANDAA] assay targeting the mutations K65R, K103NS, M184VI, Y181C, and G190A) compared to Sanger sequencing and next-generation sequencing (NGS).
Publisher: Cold Spring Harbor Laboratory
Date: 21-04-2022
DOI: 10.1101/2022.04.20.22274081
Abstract: The rapid development of vaccines in response to the COVID-19 pandemic has provided an effective tool for the management of COVID-19. However, in Africa there has been a poor uptake of COVID-19 vaccines with only 15% vaccine coverage compared to the WHO global target of 70%. One of the important drivers has been vaccine hesitancy, understanding late adopters of vaccination can provide insights into the attitudes, motivations and influences that can enhance vaccine uptake. Between January 4 – February 11, 2022, we conducted a survey among adults presenting for their first dose of a COVID-19 vaccine almost 12-months after the vaccination program began. Vaccines were free and provided at clinics and outreach centers in Harare, Zimbabwe. The questionnaire assessed environmental and in idual factors (attitudes, barriers, motivations, key influencers, and information sources) that influenced the decision to present for vaccination. Baseline socio-demographic data and responses to survey questions were summarized using descriptive statistics. Binary logistic regression models were developed to understand factors associated with vaccine confidence. 1016 adults were enrolled into the study, 508 (50%) were female, 126 (12.4%) had HIV co-infection. The median age was 30 years (IQR 22 – 39). Women were more likely to have negative views about the COVID-19 vaccine compared to men (OR 1.51 (95%CI 1.16, 1.97, p=0.002). Women compared to men and older adults (≥ 40 years) compared with youth (18-25 years) were more likely to have ‘major concerns’ about vaccines. Most concerns were about safety with 602 (59.3%) concerned about immediate and 520 (51.2%) about long-term health effects of vaccines. People living with HIV (PLWH) were more likely to perceive vaccines as safe (OR 1.71 (95%CI: 1.07, 2.74, p=0.025), effective (1.68 (95%CI: 1.07, 2.64, p=0.026) and to trust regulatory systems for approving vaccines (OR 1.79 (95% CI: 1.11, 2.89, p=0.017) compared to those without HIV. Internet users were less likely to perceive vaccines as safe (OR 0.72 (95% CI: 0.55, 0.95, p=0.021), effective (OR 0.61 (95% CI: 0.47, 0.80, p .001) or trust regulatory processes for approving vaccines (OR 0.64 (95% CI: 0.48, 0.85, p=0.002) compared to non-internet users. Social influence was a key factor in the decision to be vaccinated with family members being the primary key influencers for 560 (55.2%) participants. The most important reason for receiving the COVID-19 vaccine today for 715 (70.4%) participants was the protection of in idual health. The most trusted source of information regarding the vaccine was the Ministry of Health (79.7%) and the radio, television and social media were the preferred sources for obtaining this information. Social media was a more likely source for youth and those with higher levels of education. Improving vaccine coverage will need targeted communication strategies that address negative perceptions of vaccines and associated safety and effectiveness concerns. Leveraging normative behavior as a social motivator for vaccination will be important as close social networks are key influences of vaccination. Traditional media remains important for health communication in Africa and should be strengthened to counter social media-based misinformation that drives concerns about safety and effectiveness particularly among internet users.
Publisher: Springer Science and Business Media LLC
Date: 16-06-2021
DOI: 10.1186/S12981-021-00356-W
Abstract: Adolescents and young adults living with HIV in sub Saharan Africa are at high risk of poor adherence to antiretroviral therapy (ART) and virologic failure (VF). We conducted a randomized control trial among adolescents and young adults on ART with VF to assess the effectiveness of a community-based peer support intervention aimed at improving VF. Viral load (VL) levels were obtained at 12, 24 and 36 weeks. A subset of the participants had baseline HIV drug resistance (HIVDR) genotyped using Sanger sequencing. The participants’ median (interquartile range (IQR)) age was 18.1 (IQR: 15.1–20.0) years and half (50.5%, n = 107) were male. At week 24, the proportion of subjects with a detectable viremia was significantly lower in the intervention arm than in the standard of care (SOC) arm (76.0% (n = 79) vs. 89.0% (n = 96), p = 0.013). At Week 36, there remained a difference in the proportion of subjects with a detectable VL between the intervention arm (68.3%, n = 71) and SOC arm (79.6%, n = 86), which was trending towards statistical significance (p = 0.059). There was no difference in the probability of having a detectable VL over time between the intervention and SOC groups (adjusted odds ratio: 1.14, p = 0.439). Baseline HIVDR was observed in 44.0% of the participants in the intervention and 56.0% in the SOC group (p = 0.146). A transient effect of the peer support intervention in improving VF was observed among adolescents and young people failing ART. Trial registration : This study is registered with www.clinicaltrials.gov under the reference number: NCT02833441
Publisher: MDPI AG
Date: 07-07-2022
Abstract: Despite sufficient supply, % of the population in sub-Saharan Africa has received at least one dose of COVID-19 vaccine. Vaccine mandates have previously been effective in increasing vaccine uptake. Attitudes to COVID-19 vaccine mandates and vaccines for children in African populations are not well understood. We surveyed late-adopters presenting for COVID-19 vaccination one year after program initiation in Zimbabwe. Logistic regression models were developed to evaluate factors associated with attitudes to mandates. In total, 1016 adults were enrolled 690 (67.9%) approved of mandating vaccination for use of public spaces, 686 (67.5%) approved of employer mandates, and 796 (78.3%) approved of mandating COVID-19 vaccines for schools. In iduals of lower economic status were twice as likely as high-income in iduals to approve of mandates. Further, 743 (73.1%) participants indicated that they were extremely/very likely to accept vaccines for children. Approval of vaccine mandates was strongly associated with perceptions of vaccine safety, effectiveness, and trust in regulatory processes that approved vaccines. Vaccine hesitancy is an important driver of low vaccine coverage in Africa and can be mitigated by vaccine mandates. Overall, participants favored vaccine mandates however, attitudes to mandates were strongly associated with level of education and socioeconomic status.
Publisher: SAGE Publications
Date: 02-2015
DOI: 10.1016/J.AUSMJ.2014.10.002
Abstract: Research on trust in business collaborations is generally founded on the premises that: a) cognitive trust is initially defined within contractual procedures b) positive experiences lead to adjustments in contractual and/or informal arrangements, and c) cognitive trust is eventually supplanted by affective trust. This dynamic, process view of trust fails to capture the impact of trust experiences in external collaborations on trust emergence in a focal collaboration, and the complexity of trust co-evolution as each actor interprets and responds to the other's communication, behaviour and action. A complexity conceptualisation of trust as a self-organising, adaptive phenomenon can help us better understand the way trust develops. Through engaging with complexity theories as metaphors to enrich trust theory, trust is described as ‘self-organising’ as new cognitive, interpretive schema are evoked, and ‘adapting’ in response to trust experiences external to the collaboration. A complexity perspective evokes a new field of research questions and rich methodological opportunities.
Publisher: American Society for Microbiology
Date: 31-08-2022
DOI: 10.1128/SPECTRUM.01075-22
Abstract: Cryptococcal disease (CD) remains a leading cause of morbidity and mortality among in iduals with advanced HIV disease (AHD). Identifying point of care (POC) approaches to screening for CD in asymptomatic in iduals is important to guide therapeutic management.
Publisher: Oxford University Press (OUP)
Date: 11-12-2018
DOI: 10.1093/OFID/OFY333
Abstract: There are no host biomarkers of risk for HIV-associated cryptococcal meningitis (CM) except CD4+ T-cell deficiency. At present, serum cryptococcal antigen (CrAg) screening of those with CD4 & cells/µL is used to identify persons at risk for HIV-associated CM. We determined if plasma antibody profiles could discriminate CrAg+ from CrAg- patients. We performed serological analyses of 237 HIV-infected asymptomatic Zimbabwean patients with CD4 & cells/µL 125 CrAg- and CrAg+ but cerebrospinal fluid CrAg- by CrAg lateral flow assay. We measured plasma immunoglobulin M (IgM), immunoglobulin G (IgG) 1, and IgG2 concentrations by Luminex, and titers of Cryptococcus neoformans (Cn) glucuronoxylomannan (GXM) polysaccharide and naturally occurring Laminarin (natural Lam, a β-(1–3)-glucan linked polysaccharide)-binding IgM and IgG by enzyme-linked immunosorbent assay. GXM-IgG, -IgM, and -IgG2 levels were significantly higher in CrAg+ patients, whereas natural Lam-IgM and Lam-IgG were higher in CrAg- patients before and after adjustment for age, sex, and CD4 T-cell count, despite overlap of values. To address this variability and better discriminate the groups, we used Akaike Information Criteria to select variables that independently predicted CrAg+ status and included them in a receiver operating characteristic curve to predict CrAg status. By inclusion of CD4, GXM-IgG, GXM-IgM, and Lam-IgG, -IgG2, and -IgM, this model had an 80.4% probability (95% confidence interval, 0.75–0.86) of predicting CrAg+ status. Statistical models that include multiple serological variables may improve the identification of patients at risk for CM and inform new directions in research on the complex role that antibodies may play in resistance and susceptibility to CM.
Location: United Kingdom of Great Britain and Northern Ireland
Location: No location found
Location: Zimbabwe
Location: United States of America
No related grants have been discovered for Azure Tariro Makadzange.