John Phuka

Dr. John Phuka

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 September 2021 in The American Journal of Clinical Nutrition
Verified
Journal Article
Open access
PDF file
EPElizabeth L Prado
Elizabeth L Prado
CACharles D Arnold
Charles D Arnold
KWK. Ryan Wessells
K. Ryan Wessells
CSChristine P Stewart
Christine P Stewart
SASouheila Abbeddou
Souheila Abbeddou
KDKathryn G Dewey
Kathryn G Dewey
Small-quantity (SQ) lipid-based nutrient supplements (LNSs) provide many nutrients needed for brain development. We aimed to generate pooled estimates of the effect of SQ-LNSs on developmental outcomes (language, social-emotional, motor, and executive function), and to identify study-level and individual-level modifiers of these effects. We conducted a 2-stage meta-analysis of individual participant data from 14 intervention against control group comparisons in 13 randomized trials of SQ-LNSs provided to children age 6–24 mo (total n = 30,024). In 11–13 intervention against control group comparisons (n = 23,588–24,561), SQ-LNSs increased mean language (mean difference: 0.07 SD; 95% CI: 0.04, 0.10 SD), social-emotional (0.08; 0.05, 0.11 SD), and motor scores (0.08; 95% CI: 0.05, 0.11 SD) and reduced the prevalence of children in the lowest decile of these scores by 16% (prevalence ratio: 0.84; 95% CI: 0.76, 0.92), 19% (0.81; 95% CI: 0.74, 0.89), and 16% (0.84; 95% CI: 0.76, 0.92), respectively. SQ-LNSs also increased the prevalence of children walking without support at 12 mo by 9% (1.09; 95% CI: 1.05, 1.14). Effects of SQ-LNSs on language, social-emotional, and motor outcomes were larger among study populations with a higher stunting burden (≥35%) (mean difference: 0.11–0.13 SD; 8–9 comparisons). At the individual level, greater effects of SQ-LNSs were found on language among children who were acutely malnourished (mean difference: 0.31) at baseline; on language (0.12), motor (0.11), and executive function (0.06) among children in households with lower socioeconomic status; and on motor development among later-born children (0.11), children of older mothers (0.10), and children of mothers with lower education (0.11). Child SQ-LNSs can be expected to result in modest developmental gains, which would be analogous to 1–1.5 IQ points on an IQ test, particularly in populations with a high child stunting burden. Certain groups of children who experience higher-risk environments have greater potential to benefit from SQ-LNSs in developmental outcomes. This trial was registered at www.crd.york.ac.uk/PROSPERO as CRD42020159971.

5 March 2021 in JMIR Public Health and Surveillance
Verified
Journal Article
Open access
ONOnicio Leal Neto
Onicio Leal Neto
SHSimon Haenni
Simon Haenni
JPJohn Phuka
John Phuka
LOLaura Ozella
Laura Ozella
DPDaniela Paolotti
Daniela Paolotti
GLGuilherme Lichand
Guilherme Lichand
Background: Multimodal approaches have been shown to be a promising way to collect data on child development at high frequency, combining different data inputs (from phone surveys to signals from noninvasive biomarkers) to understand children’s health and development outcomes more integrally from multiple perspectives. Objective: The aim of this work was to describe an implementation study using a multimodal approach combining noninvasive biomarkers, social contact patterns, mobile surveying, and face-to-face interviews in order to validate technologies that help us better understand child development in poor countries at a high frequency. Methods: We carried out a mixed study based on a transversal descriptive analysis and a longitudinal prospective analysis in Malawi. In each village, children were sampled to participate in weekly sessions in which data signals were collected through wearable devices (electrocardiography [ECG] hand pads and electroencephalography [EEG] headbands). Additionally, wearable proximity sensors to elicit the social network were deployed among children and their caregivers. Mobile surveys using interactive voice response calls were also used as an additional layer of data collection. An end-line face-to-face survey was conducted at the end of the study. Results: During the implementation, 82 EEG/ECG data entry points were collected across four villages. The sampled children for EEG/ECG were 0 to 5 years old. EEG/ECG data were collected once a week. In every session, children wore the EEG headband for 5 minutes and the ECG hand pad for 3 minutes. In total, 3531 calls were sent over 5 weeks, with 2291 participants picking up the calls and 984 of those answering the consent question. In total, 585 people completed the surveys over the course of 5 weeks. Conclusions: This study achieved its objective of demonstrating the feasibility of generating data through the unprecedented use of a multimodal approach for tracking child development in Malawi, which is one of the poorest countries in the world. Above and beyond its multiple dimensions, the dynamics of child development are complex. It is the case not only that no data stream in isolation can accurately characterize it, but also that even if combined, infrequent data might miss critical inflection points and interactions between different conditions and behaviors. In turn, combining different modes at a sufficiently high frequency allows researchers to make progress by considering contact patterns, reported symptoms and behaviors, and critical biomarkers all at once. This application showcases that even in developing countries facing multiple constraints, complementary technologies can leverage and accelerate the digitalization of health, bringing benefits to populations that lack new tools for understanding child well-being and development.

29 December 2022 in eClinicalMedicine
Verified
Journal Article
Open access
UMUpendo L. Mseka
Upendo L. Mseka
JMJonathan Mandolo
Jonathan Mandolo
KNKenneth Nyoni
Kenneth Nyoni
ODOscar Divala
Oscar Divala
DKDzinkambani Kambalame
Dzinkambani Kambalame
ACAnnie Chauma-Mwale
Annie Chauma-Mwale
The B.1.1.529 (Omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the fourth COVID-19 pandemic wave across the southern African region, including Malawi. The seroprevalence of SARS-CoV-2 antibodies and their association with epidemiological trends of hospitalisations and deaths are needed to aid locally relevant public health policy decisions. We conducted a population-based serosurvey from December 27, 2021 to January 17, 2022, in 7 districts across Malawi to determine the seroprevalence of SARS-CoV-2 antibodies. Serum samples were tested for antibodies against SARS-CoV-2 receptor binding domain using WANTAI SARS-CoV-2 Receptor Binding Domain total antibody commercial enzyme-linked immunosorbent assay (ELISA). We also evaluated COVID-19 epidemiologic trends in Malawi, including cases, hospitalisations and deaths from April 1, 2021 through April 30, 2022, collected using the routine national COVID-19 reporting system. A multivariable logistic regression model was developed to investigate the factors associated with SARS-CoV-2 seropositivity. Serum samples were analysed from 4619 participants (57% female; 60% aged 18-50 years), of whom 878/3794 (23%) of vaccine eligible adults had received a single dose of any COVID-19 vaccine. The overall assay-adjusted seroprevalence was 83.7% (95% confidence interval (CI), 79.3%-93.4%). Seroprevalence was lowest among children <13 years of age (66%) and highest among adults 18-50 years of age (82%). Seroprevalence was higher among vaccinated compared to unvaccinated participants (1 dose, 94% vs. 77%, adjusted odds ratio 4.89 [95% CI, 3.43-7.22]; 2 doses, 97% vs. 77%, aOR 6.62 [95% CI, 4.14-11.3]). Urban residents were more likely to be seropositive than those from rural settings (91% vs. 78%, aOR 2.76 [95% CI, 2.16-3.55]). There was at least a two-fold reduction in the proportion of hospitalisations and deaths among the reported cases in the fourth wave compared to the third wave (hospitalisations, 10.7% (95% CI, 10.2-11.3) vs. 4.86% (95% CI, 4.52-5.23), p < 0.0001; deaths, 3.48% (95% CI, 3.18-3.81) vs. 1.15% (95% CI, 1.00-1.34), p < 0.0001). We report reduction in proportion of hospitalisations and deaths from SARS-CoV-2 infections during the Omicron variant dominated wave in Malawi, in the context of high SARS-CoV-2 seroprevalence and low COVID-19 vaccination coverage. These findings suggest that COVID-19 vaccination policy in high seroprevalence settings may need to be amended from mass campaigns to targeted vaccination of reported at-risk populations. Supported by the Bill and Melinda Gates Foundation (INV-039481).

3 April 2023 in Nutrients
Verified
Journal Article
Open access
PDF file
BLBlessings H Likoswe
Blessings H Likoswe
BCBernadette Chimera-Khombe
Bernadette Chimera-Khombe
NPNoel Patson
Noel Patson
ASApatsa Selemani
Apatsa Selemani
IPIsabel Potani
Isabel Potani
KMKenneth MPHATSO Maleta
Kenneth MPHATSO Maleta
The World Health Organisation (WHO) recommends that severe wasting and/or oedema should be treated with ready-to-use therapeutic food (RUTF) at a dose of 150–220 kcal/kg/day for 6–8 weeks. Emerging evidence suggests that variations of RUTF dosing regimens from the WHO recommendation are not inferior. We aimed to assess the comparative efficacy and effectiveness of different RUTF doses and durations in comparison with the current WHO RUTF dose recommendation for treating severe wasting and/or oedema among 6–59-month-old children. A systematic literature search identified three studies for inclusion, and the outcomes of interest included anthropometric recovery, anthropometric measures and indices, non-response, time to recovery, readmission, sustained recovery, and mortality. The study was registered with PROSPERO, CRD 42021276757. Only three studies were eligible for analysis. There was an overall high risk of bias for two of the studies and some concerns for the third study. Overall, there were no differences between the reduced and standard RUTF dose groups in all outcomes of interest. Despite the finding of no differences between reduced and standard-dose RUTF, the studies are too few to conclusively declare that reduced RUTF dose was more efficacious than standard RUTF.

16 July 2024 in JMIR Public Health and Surveillance
Verified
Journal Article
Open access
MVMariana Gasparoto Pereira Valerio
Mariana Gasparoto Pereira Valerio
BLBeverly Shaila Laher
Beverly Shaila Laher
JPJohn Phuka
John Phuka
GLGuilherme Lichand
Guilherme Lichand
DPDaniela Paolotti
Daniela Paolotti
ONOnicio Leal Neto
Onicio Leal Neto
Background: Cholera-like diarrheal disease (CLDD) outbreaks are complex and influenced by environmental factors, socioeconomic conditions, and population dynamics, leading to limitations in traditional surveillance methods. In Malawi, cholera is considered an endemic disease. Its epidemiological profile is characterized by seasonal patterns, often coinciding with the rainy season when contamination of water sources is more likely. However, the outbreak that began in March 2022 has extended to the dry season, with deaths reported in all 29 districts. It is considered the worst outbreak in the past 10 years. Objective: This study aims to evaluate the feasibility and outcomes of participatory surveillance (PS) using interactive voice response (IVR) technology for the early detection of CLDD outbreaks in Malawi. Methods: This longitudinal cohort study followed 740 households in rural settings in Malawi for 24 weeks. The survey tool was designed to have 10 symptom questions collected every week. The proxies’ rationale was related to exanthematic, ictero-hemorragica for endemic diseases or events, diarrhea and respiratory/targeting acute diseases or events, and diarrhea and respiratory/targeting seasonal diseases or events. This work will focus only on the CLDD as a proxy for gastroenteritis and cholera. In this study, CLDD was defined as cases where reports indicated diarrhea combined with either fever or vomiting/nausea. Results: During the study period, our data comprised 16,280 observations, with an average weekly participation rate of 35%. Maganga TA had the highest average of completed calls, at 144.83 (SD 10.587), while Ndindi TA had an average of 123.66 (SD 13.176) completed calls. Our findings demonstrate that this method might be effective in identifying CLDD with a notable and consistent signal captured over time (R2=0.681404). Participation rates were slightly higher at the beginning of the study and decreased over time, thanks to the sensitization activities rolled out at the CBCCs level. In terms of the attack rates for CLDD, we observed similar rates between Maganga TA and Ndindi TA, at 16% and 15%, respectively. Conclusions: PS has proven to be valuable for the early detection of epidemics. IVR technology is a promising approach for disease surveillance in rural villages in Africa, where access to health care and traditional disease surveillance methods may be limited. This study highlights the feasibility and potential of IVR technology for the timely and comprehensive reporting of disease incidence, symptoms, and behaviors in resource-limited settings.

1 December 2019 in Public Health Nutrition
Verified
Journal Article
Closed access
PDF file
CSCourtney H Schnefke
Courtney H Schnefke
CTChrissie Thakwalakwa
Chrissie Thakwalakwa
MMMary K Muth
Mary K Muth
JPJohn Phuka
John Phuka
JCJennifer Coates
Jennifer Coates
VFValerie L Flax
Valerie L Flax
Objective: To investigate preferences for and ease-of-use perceptions of different aspects of printed and digitally displayed photographic portion-size estimation aids (PSEA) in a low-resource setting and to document accuracy of portion-size selections using PSEA with different visual characteristics. Design: A convergent mixed-methods design and stepwise approach were used to assess characteristics of interest in isolation. Participants served themselves food and water, which were weighed before and after consumption to measure leftovers and quantity consumed. Thirty minutes later, data collectors administered a meal recall using a PSEA and then a semi-structured interview. Setting: Blantyre and Chikwawa Districts in the southern region of Malawi. Participants: Ninety-six women, aged 18-45 years. Results: Preferences and ease-of-use perceptions favoured photographs rather than drawings of shapes, three and five portion-size options rather than three with four virtual portion-size options, a 45 degrees rather than a 90 degrees photograph angle, and simultaneous rather than sequential presentation of portion-size options. Approximately half to three-quarters of participants found the portion-size options represented appropriate amounts of foods or water consumed. Photographs with three portion sizes resulted in more accurate portion-size selections (closest to measured consumption) than other format and number of portion-size option combinations. A 45 degrees angle and simultaneous presentation were more accurate than a 90 degrees angle and sequential presentation of images. Conclusions: Results from testing PSEA visual characteristics separately can be used to generate optimal PSEA, which can improve participants' experiences during meal recalls.