Malaria Journal

The innate immune response of Anopheles mosquitoes is closely associated with the successful development of Plasmodium parasites and their subsequent transmission to humans. However, the extent to which mosquito immune activation correlates with parasite burden during early sporogonic development, and how additional factors may be linked to variation in this early immune response, remains only partly understood. In this study, we examined the immune responses of individual Anopheles coluzzii mosquitoes fed on Plasmodium falciparum infected blood with identical gametocytemia, yet exhibiting different infection intensities at the ookinete stage. We focused on the critical window of ookinete maturation and midgut traversal (12 to 36 hours post-infection), a key phase for parasite establishment, while minimizing confounding factors such as mosquito age, microbiota composition, blood meal variability, and experimental noise. Ookinete burden was estimated in individual mosquitoes by quantifying four well established stage-specific transcripts (ctrp, warp, soap, and cht1), allowing stratification into "low" and "high" ookinete load groups prior to RNA-seq analysis. Transcriptional profiling revealed clear differences between these two conditions, with mosquitoes carrying lower ookinete loads exhibiting stronger upregulation of immune-related genes compared to those with higher burdens, indicating that the reduced parasite establishment during the very early stages of infection is strictly associated with an effective immune activation. Notably, genes involved in L-arginine homeostasis were significantly modulated, highlighting a pathway not extensively explored in the context of mosquito anti-Plasmodium defense. Overall, our findings show that ookinete burden correlates with distinct mosquito transcriptional states during early infection and emphasize the value of ookinete-specific transcripts quantification for dissecting early vector-parasite interactions.

Introduction: The continuing high and inequitable global malaria burden requires improved methods to understand trends and target control. Current methods often involve infection prevalence surveys, but additional parasitological measures could increase precision in estimating infection burdens of communities. Methods: Focusing on the country with most malaria globally, examinations of slides from 10,651 children under five sampled in the 2021 national Malaria Indicator Survey in Nigeria were performed to measure asexual parasite densities in infected children and discriminate sexual stages and species. Variation in these indices among the six different geopolitical zones and 37 individual states including the Federal Capital Territory were compared with the variation indicated by infection prevalence alone. Results: Among the six major geopolitical zones, only one had significantly higher asexual parasite prevalence than others, but parasite densities within infected children revealed more significant variation among the different zones. Comparing results for 2021 with previous data from 2018, one zone showed lower asexual parasite prevalence and two had lower sexual parasite prevalence, but three had higher asexual parasite densities in infected children. Variation in parasite densities among individual states also highlighted significant geographical and temporal differences, extending the detection of heterogeneity within each geopolitical zone. Overall trends were driven by the predominant parasite species Plasmodium falciparum as prevalence and density of the other species were much lower. Conclusions: Findings indicate that understanding complex patterns of geographical and temporal variation is enhanced by including asexual parasite density measurement, providing opportunities for more precise targeting of malaria control within high burden countries.

Background: Severe malaria remains a major cause of hospitalization in malaria-endemic sub-Saharan Africa, and anemia is among its most frequent severity criteria. Data on the impact of anemia on hospital length of stay (LOS) among adults with severe malaria remain limited in Central Africa. We assessed the impact of anemia on LOS among adults hospitalized for severe malaria in Brazzaville, Republic of Congo. Methods: We conducted a cross-sectional, descriptive, and analytic study of medical records from adult patients ([&ge;]18 years) diagnosed with severe malaria (WHO criteria) and admitted to four hospitals in Brazzaville between January 2020 and December 2024. We dichotomized LOS as short (<5 days) or prolonged ([&ge;]5 days). Multivariable logistic regression, using a backward stepwise procedure, identified factors independently associated with prolonged LOS; isolated hemoglobinuria served as the reference severity category. Results: Among 523 patients hospitalized for severe malaria, 296 met the inclusion criteria. Median age was 25.5 years (IQR 20-40); 51.7% were female, and 82.1% had a low socioeconomic status. Median hemoglobin was 10.55 g/dL, and median LOS was 4 days (IQR 3-5). In multivariable analysis, prolonged LOS was independently associated with delay to consultation (aOR 1.25/day, 95% CI 1.09-1.44), isolated anemia (aOR 7.07, 1.23-40.55), convulsions (aOR 5.86, 1.81-18.97), prostration (aOR 4.42, 1.21-16.2), and impaired consciousness (aOR 4.29, 1.17-15.7). The strongest associations involved combined severity criteria: anemia with prostration (aOR 8.58), anemia with jaundice or hemoglobinuria (aOR 16.21), and impaired consciousness with anemia (aOR 33.31). Conclusions: Anemia is a major, potentially modifiable determinant of prolonged hospitalization in adults with severe malaria, with a markedly amplified effect when combined with neurologic impairment. Early anemia screening, improved access to safe blood transfusion, and reduced delays to care could shorten hospital stays and ease the burden on health systems in this setting.

Artemisinin partial resistance (ART R) associated Plasmodium falciparum Kelch13 mutations is expanding across Africa. However, their population level consequences remain poorly understood, particularly in settings of moderate to high malaria transmission. We investigated associations between Kelch13 and partner drug mutation prevalence and monthly confirmed malaria incidence across 16 Ugandan districts from 2017 to 2022, using integrated molecular, epidemiological, climatic, malaria control, and antimalarial resistance data and negative binomial regression. Combined prevalence of WHO validated and candidate Kelch13 mutations increased over the study period. Each 10 percentage point increase in Kelch13 prevalence was associated with a 13.1% higher incidence after multivariable adjustment (aIRR 1.131, 95% CI 1.090 to 1.174). Furthermore, each 10% increase in pfcrt K76T was associated with a 24% increase in malaria transmission. As expected, ITN distribution >80%, IRS coverage >90%, and higher altitude were associated with lower incidence, whereas temperatures of 25 to 30C, relative humidity of 60 to 80%, and higher precipitation were associated with higher incidence. The persistence of the Kelch13 and pfcrt K76T association after adjustment suggests that expanding ART R associated parasite populations are independently associated with malaria incidence. The relationship may be bidirectional. These findings support interpreting ART R within its ecological and intervention context and integrating molecular, epidemiological, and malaria control surveillance to safeguard antimalarial efficacy.

Immunity against Plasmodium falciparum malaria is acquired slowly and incompletely through repeated infections, leading to differing levels of protection among individuals based on their history of exposure to the disease. Since malaria is a climate sensitive vector-borne disease, immunological history is shaped by the local climate. Nonetheless, compartmental malaria models, which may be used to inform policy, implicitly represent immunity as a population-average trait --- an assumption that can lead to incorrect estimates of clinical prevalence by age, and of the overall burden of malaria. As the rate at which immunity is acquired depends on transmission intensity, and therefore on background climatic conditions, the error introduced by this assumption is expected to be climate-sensitive. We quantify how individual exposure histories shape community-level prevalence, and identify the age groups for which resolving immunity individually matters most across climatic regimes. For this, we introduce VECTRI-ABM, a grid-based framework coupling the climate-driven vector component of the VECTRI model to an agent-based representation of the human population, resolving immunity at the individual level. The framework was calibrated against entomological and epidemiological observations from Dielmo and Ndiop (Senegal, 1990--2003) and evaluated against reported entomological inoculation rates, Malaria Atlas Project estimates of parasite rate in children aged 2--10, and confirmed cases from Senegal's National Malaria Control Program (PNLP). We then applied it across Senegal and The Gambia, which encompass a pronounced Sahelian-to-tropical rainfall gradient, and compared simulations in which immunity develops individually against a counterfactual where agents carry the local population-average immunity, thus mimicking the assumption made by standard models. Results show that the averaging approach misallocates burden across age, underestimating clinical prevalence in children, especially so in the wettest high-transmission regions, and overestimating adult asymptomatic reservoirs, with implications for transmission-targeting interventions. We find that the simpler approach to immunity is adequate for immunologically mature populations, typically above 15 years of age, and that the error it introduces elsewhere is climate-dependent.

Genomic tools can support malaria control policy through surveillance of Plasmodium falciparum populations, tracking antimalarial drug resistance, pfhrp2/3 deletions that compromise rapid diagnostic tests, and selection at the circumsporozoite protein (PfCSP) vaccine target, as well as through molecular correction of therapeutic efficacy studies (TES). Multiplex Amplicons for Drug, Diagnostic, Diversity, and Differentiation Haplotypes using Targeted Resequencing (MAD4HatTeR), a comprehensive amplicon sequencing panel covering up to 276 targets, supports these applications but is tailored to research rather than routine programmatic use. We developed P. falciparum Public Health Amplicon Sequencing Tool (PfPHAST), a 56-target derivative of MAD4HatTeR spanning drug resistance loci, pfhrp2/3 deletion, PfCSP genotyping, non-falciparum species identification, and 20 high-heterozygosity microhaplotype loci for TES classification. We compared PfPHAST and MAD4HatTeR using laboratory strain controls, including two-strain dilution series and a five-strain mixture, across parasite densities of 100 to 10,000 parasites/L. At matched per-target depth, PfPHAST achieved a higher quality-control pass rate than MAD4HatTeR (94.4% versus 90.0%) and distributed reads more evenly across targets. The panels showed comparable recall and precision for drug resistance codons and microhaplotypes, reaching near-complete recall above 40% within-sample allele frequency (WSAF) at all densities, with reduced sensitivity for minor alleles below 10% WSAF at low parasite density in both panels. Observed and expected WSAF correlated strongly for both panels, and both resolved a five-strain polyclonal mixture, including a 5% minor strain. By concentrating sequencing capacity on targets of greatest programmatic relevance, PfPHAST offers a scalable, lower-cost alternative to comprehensive research panels without sacrificing performance on shared targets, complementing MAD4HatTeR for routine molecular malaria surveillance.

Blood-stage vaccines (BSVs) against malaria offer a promising avenue for reducing parasite burden and transmission, yet their efficacy is challenging to interpret across different trial phases. In this study we develop a simple mechanistic within-host mathematical model of Plasmodium falciparum asexual parasitaemia. We fit this model to individual-level data from the phase I/IIa RH5.1 trial and estimate the relationship between vaccine efficacy and RH5 antibody titres, enabling the quantitative prediction of vaccine-impact on public health outcomes. We show that small reductions in erythrocyte invasion rate can lead to substantial decreases in probability of exceeding parasitaemia thresholds and transmission potential. Our framework provides a flexible, biologically motivated method for interpreting early-phase trial data and can inform future trial design, vaccine evaluation and integration into broader malaria control strategies.

Sporozoites, the infectious stage of Plasmodium malaria parasites, must invade two different tissues in two very different hosts to ensure transmission: the mosquito salivary glands and the human liver. Whether infectivity to hepatocytes is affected by physiological components, such as the availability of nutrients within the Anopheles female, is not well understood. Here we show that Plasmodium falciparum sporozoite infectivity to hepatocytes is increased if mosquitoes take an additional blood meal while oocysts are developing. Infection rates of HC04.J7 hepatocytes at 24 h were 1.8-fold higher for P. falciparum salivary gland sporozoites isolated from Anopheles gambiae females fed twice (2BF) compared to those which only received the infectious blood meal (1BF). This increase in infectivity was observed at an early infection timepoint (day 11) and was accompanied by a marked shift in the transcriptional profiles of 2BF salivary gland sporozoites, identifying genes likely involved in infection and development in the mammalian host. Overall, our data reveal new factors potentially involved in sporozoite infectivity, and have broad implications for understanding transmission of malaria in endemic areas where multiple blood meals commonly shape available resources for adult female mosquitoes.

BackgroundIn Ethiopia as other Sub-Sharan African countries malaria in pregnancy is a major public health threat particularly in the rural communities. Immunosuppression during pregnancy increases the risk of placental malaria; this, in turn, leads to anemia, low birth weight, preterm delivery, and stillbirth, causing severe complications that pose a life-threatening risk to both the mother and fetus. Hence, this study is aimed to assess the prevalence of malaria, and associated factors among pregnant women attending antenatal clinics in Damot Gale district, South Ethiopia. MethodAn institutional-based cross sectional study was conducted from March 1 to May 30, 2024. A multistage sampling technique and pre-tested semi-structured questionnaires were used for data collection. Using standard parasitological methods, blood samples collected from 389 participants were analyzed through microscopic examination of Giemsa-stained thick and thin blood films. Logistic regression was used to assess factors associated with malaria. Adjusted odds ratio with 95% confidence interval was calculated and P-value < 0.05 was considered statistically significant. ResultsIn this study the prevalence of malaria among pregnant women was 10.5% (95% CI: 7.7-13.6%). Among the malaria-positive pregnant women (9%) were P. falciparum infected, followed by P. vivax (1.3) and mixed infections (0.2%). In the multivariate analysis, multigravdae (AOR = 0.358; 95% CI: 0.14-0.92), utilization of LLINs (AOR = 0.286; 95% CI: 0.119-0.687) and use of IRS (AOR = 0.068; 95% CI: 0.027-0.172) were significantly associated with malaria among pregnant women. ConclusionMalaria is still a public health problem among pregnant women in Damote-gale district. The present study indicated that adequate distribution and proper utilization of bed nets In addition seasonal proper spray of IRS might be helpful to prevent and control malaria.

BackgroundMalaria in pregnancy (MiP) imposes a substantial economic burden on households in sub-Saharan Africa. We estimated household costs of MiP and their distribution across wealth quintiles among HIV-uninfected pregnant women in western Kenya receiving intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP), dihydroartemisinin-piperaquine (DP), or dihydroartemisinin-piperaquine plus provider education. MethodsThis study was nested within a three-armed, pragmatic, open-label, cluster-randomised trial across 15 health facilities over 10 months. Exit interviews were conducted during the second and third trimesters, approximately 5-6 months after the start of the intervention period. Direct and indirect household costs from the most recent malaria episode were compared with income to estimate catastrophic health expenditure (CHE). Costs were analysed using mixed-effects generalised linear model and their distribution across wealth quintiles using the concentration index. Cost data collected in 2020 (Kenyan shillings) were inflated and converted to 2024 US dollars. FindingsAmong 1,189 participants, 247 (21%) self-reported having sought care for MiP (212 outpatients, 24 inpatients, 11 unspecified). Mean costs were USD 24.9 for outpatient and USD 57.1 for inpatient care per episode. Indirect costs accounted for 87% and 70% of outpatient and inpatient costs, respectively. The mean outpatient malaria costs were equivalent to six or more days while inpatient costs were half a month or more of the minimum wages in the study area. The incidence of CHE for outpatient care was 8%, and neither outpatient costs nor CHE varied between wealth quintiles (concentration index =0.02, p=0.571 and 0.01, p=0.304, respectively). ConclusionsMiP imposes a substantial economic burden on households in western Kenya, despite a national policy of free maternal health services. Most costs arose from productivity losses rather than payments for care; financial protection therefore depends on the prevention of malaria episodes.

Implementing vector control interventions against infectious diseases is operationally challenging, with delivery and population uptake taking considerable time within a community. Studies have suggested that the slow mass drug administration (MDA) of the endectocide, ivermectin, may have contributed to the lower epidemiological impact against malaria observed in recent cluster-randomised controlled trials, although evidence supporting this hypothesis is lacking. It is unclear whether interventions which have short but highly effective durations of entomological impact are more impactful than tools which kill the same number of mosquitoes but over a longer period. Transmission dynamics mathematical models can be used to explore the trade-offs between product profiles and investigate how different implementation periods could influence disease control. First, we use a simple vector-borne disease compartmental model to explore the epidemiological impact of killing the same number of mosquitoes over 10, 30 or 90 days. We find that for different mosquito-killing periods, the total number of cases averted is similar, although the observable impact may depend on when efficacy is assessed. Secondly, we adapted an existing malaria transmission model and simulated the fast and slow deployment of an effective endectocide MDA campaign in different seasonal settings. In perennial and seasonal settings and for a given coverage, slow MDA deployment averts more clinical cases of malaria than a fast synchronised distribution (completed in a single day, although the difference was modest). The benefits of the intervention depend on how well-timed a deployment is relative to the peak of the transmission season, with the efficacy of an ivermectin-like endectocide MDA being up to approximately 42% lower if started late. The work indicates that the time taken to complete MDA campaigns is unlikely to drive major differences in the effectiveness of short-lived endectocides and showcases how transmission dynamics models can be used to support epidemiological trial interpretation.

The radical cure of Plasmodium vivax requires treatment of the dormant liver stages with either primaquine or tafenoquine but is constrained by the risk of severe hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. A revised case-management package, New Primaquine Treatment (NPT), was designed to support safe radical cure in Indonesia, and included G6PD screening, targeting high dose primaquine and early clinical review. A decision-tree model was constructed using individual-level data from a study, that treated patients with 7mg/kg primaquine according to their G6PD activity: primaquine administered over 7 days (G6PD normal individuals), 14 days (individuals with intermediate G6PD deficiency), or 8 weeks (if severely G6PD deficient). The model incorporated costs, adverse events, and P. vivax recurrence over a six-month time horizon. A business-as-usual comparator was created using historical P. vivax recurrence data for Indonesia overall and the three provinces separately. The primary outcome was disability-adjusted life-years (DALYs) averted. Costs were analyzed from health system and societal perspectives, and incremental cost-effectiveness ratios (ICERs) were compared with Indonesias Health Technology Assessment recommended willingness-to-pay thresholds of 1 and 3 gross domestic product per capita (US$4,925 and $14,475). One-way and probabilistic sensitivity analyses were conducted to assess uncertainty. Overall NPT averted 0.0011 DALYs per patient with an incremental cost of US$7.40 per patient from a health system perspective. This resulted in an ICER of US$6,636 per DALY averted, which was not cost-effective at the $4,925 threshold. Cost-effectiveness varied across settings: from US$5,098 per DALY averted in Papua to US$20,051 per DALY averted in southern Sumatra and US$80,825 per DALY averted in northern Sumatra. The ICER reduced when the societal perspective was included, with NPT cost-effective in Indonesia overall ($2,261/DALY averted) and in Papua ($675/DALY averted). The risk of P. vivax recurrence and intervention costs were the most influential parameters on the ICER. Overall, NPT was between the 1-3x GDP per capita cost-effectiveness thresholds in Indonesia; however, cost-effectiveness varied significantly across settings, indicating that NPT may not be an optimal use of resources in areas with low incidence.

Background Despite substantial improvements in maternal and child health over the past two decades, preventable maternal and neonatal morbidity and mortality remain major public health concerns in rural Bangladesh. Community-based interventions involving Community Volunteers (CVs), Community Groups (CGs), and Community Support Groups (CSGs) have been introduced to strengthen maternal and child health (MCH) services through health promotion, community engagement, and improved linkage with primary healthcare facilities. This study explored the roles, challenges, and opportunities of these community-based platforms in improving maternal and child health services. Methods A qualitative study was conducted in Kalaroa Upazila of Satkhira District, Bangladesh, between July and October 2020. Data were collected through focus group discussions and in-depth interviews with mothers, Community Volunteers, Community Group members, and Community Support Group members. Participants were purposively selected to capture diverse experiences from intervention and comparison areas. Interviews were conducted using semi-structured guides, audio-recorded with informed consent, transcribed verbatim, translated into English, and analyzed thematically using an inductive approach. Results Participants from intervention areas demonstrated greater knowledge of birth preparedness, antenatal care, pregnancy danger signs, institutional delivery, postnatal care, and newborn care than those from comparison areas. Community Volunteers, CGs, and CSGs played important roles in identifying pregnant women, conducting household counselling, promoting skilled maternal healthcare, facilitating referrals, and strengthening community participation. Participants perceived that these activities increased maternal awareness, improved health-seeking behaviour, and enhanced utilization of maternal and newborn health services. However, persistent barriers, including socio-cultural beliefs, financial constraints, transportation difficulties, shortages of skilled healthcare providers, and inadequate logistical support for community volunteers, continued to limit equitable access to quality services. Participants recommended strengthening community awareness programmes, improving community clinic readiness, enhancing referral systems, and providing regular training and supportive supervision for community-based health workers. Conclusions Community-based maternal health interventions involving Community Volunteers, Community Groups, and Community Support Groups contribute to improved maternal knowledge, health-seeking behaviour, and utilization of essential maternal and newborn health services in rural Bangladesh. Sustaining these gains will require stronger primary healthcare services, continued community engagement, and targeted strategies to address persistent health system and socio-cultural barriers. These findings provide important evidence for strengthening community-based maternal and child health programmes in Bangladesh and similar resource-constrained settings.

Aedes aegypti, an important vector of several arboviral diseases, is highly adapted to human-associated environments and commonly exploits anthropogenic water-holding containers for breeding. Understanding the ecological factors governing oviposition-site selection is essential for developing sustainable vector control strategies. Previous studies have established that microbial communities in breeding waters influence mosquito oviposition-site selection through the production of volatile organic compounds. Importantly, rapid urbanization in India has increased the availability of artificial breeding habitats for Ae. aegypti, potentially facilitating the transmission and persistence of arboviral diseases. However, the composition of bacterial communities in these larval habitats and their potential role in shaping the oviposition behavior of Ae. aegypti remain poorly characterized in the Indian context. Here, we investigated the bacterial diversity and community composition of Aedes larval habitats during the 2024 Zika and chikungunya outbreaks in Pune, India. Water samples, collected from artificial urban containers and natural freshwater habitats, were subjected to 16S rRNA amplicon sequencing. Artificial breeding habitats exhibited significantly higher bacterial diversity and were enriched with Enterobacter spp. compared with natural habitats. Oviposition bioassays further demonstrated a strong preference of gravid Ae. aegypti females for Enterobacter-conditioned water. GCMS analysis of bacterial suspension identified indole as a prominent volatile metabolite associated with Enterobacter, suggesting its possible role in mediating oviposition site selection. Together, these findings provide insights into the microbial and chemical ecology of Ae. aegypti breeding habitats and establish a basis for investigating microbial volatile cues as potential targets for vector surveillance and environmentally sustainable attract-and-kill strategies.

Epigenetic processes play important roles in the biology of the malaria parasite Plasmodium falciparum. We recently showed that Plasmodium histones are not only acetylated and methylated but also lactylated. This new epigenetic mark could form a particularly important axis of host-parasite signalling because severe malaria is often characterised by hyperlactataemia. In the human host this can cause respiratory distress, which is potentially fatal. For the parasite, it could be advantageous to sense this state of pathology and respond by modulating virulence. Virulence processes known to be under epigenetic control include antigenic variation, invasion switching and conversion to sexual gametocytes, i.e. gametocytogenesis. Here, we investigated the influence of lactate on gametocytogenesis. Hyperlactataemia in malaria patients is defined as [&ge;] 5mM blood lactate and we confirmed that in laboratory culture, adding 5mM L-lactate was sufficient to boost gametocytogenesis. Expression of the GDV-1 gene increased within one cell cycle of asexual parasites being exposed to L-lactate, suggesting that the canonical epigenetic switch for gametocytogenesis was involved: GDV-1 regulates epigenetic de-repression of the gene encoding the master transcription factor for gametocytogenesis, AP2-G. Indeed, parasite histones became rapidly lactylated after L-lactate exposure and chromatin profiling by CUT&Tag detected inducible lactylation of chromatin specifically upstream of the AP2-G gene, and also of the antisense RNA that regulates GDV-1. Thus L-lactate joins S-adenosylmethionine as a metabolite that can epigenetically regulate gametocytogenesis in P. falciparum.

RTS,S/AS01 (RTS,S) is one of two WHO-recommended malaria vaccines for children in moderate-to-high transmission settings. Yet, no validated immune correlate of protection (CoP) has been established for this vaccine. We selected 16 biomarkers to further assess as candidate CoPs, based largely on their ability to well-predict post-challenge outcomes in a previous integrative correlates analysis of two phase 2a controlled human malaria infection (CHMI) studies, Malaria-068 and Malaria-071. We evaluated the predictive power of these 16 biomarkers in two additional phase 2a CHMI studies, Malaria-092 and Malaria-102, to confirm these candidate CoPs in new malaria vaccine trials. In MAL092, malaria-naive volunteers were challenged three months after a series of two or three doses of RTS,S/AS01, and in MAL102, a subset were boosted nine months later and re-challenged after three weeks. The 16 biomarkers included Plasmodium falciparum circumsporozoite protein (CSP)-specific IgG antibodies targeting the CSP NANP-repeat region (CSP IgG ELISA), NANP repeat-specific antibody binding to human Fc gamma receptors (FcgRs), CSP-specific antibody Fc effector functions, total NANP6-specific serum Ig measured by biolayer interferometry (BLI), and NANP6-specific IgG1 antibodies measured by binding antibody multiplex assay. Immunogenicity analyses confirmed that the vaccine regimens elicited robust immune responses, including multiple biomarkers not previously reported on, in both trials. In MAL092, participants clustered into two distinct immunogenicity profiles that overlapped with malaria protection status. In univariate logistic regression analyses, most biomarkers were significantly associated with protection when measured on the day of challenge in both trials. Notably, the same three biomarkers ranked as top correlates in both trials (FCGR2AH NANP6, FCGR2AR NANP6, and FCGR2B NANP6; all adjusted p-values <0.001), with similar effect sizes across studies. Despite these strong associations, no biomarker demonstrated significantly better individual-level predictive performance than CSP IgG ELISA. In MAL092, CSP IgG ELISA achieved an area under the curve (AUC) [95% confidence interval (CI)] of 0.74 (0.63, 0.84), compared with AUCs of 0.76 - 0.78 for the top five biomarkers, all of which reflected NANP6-specific Fc{gamma}R binding (all adjusted p-values > 0.37 versus CSP IgG ELISA). Predictive models trained on data from two prior CHMI studies and applied to MAL092 and MAL102 identified a model based on FCGR2B NANP6 (validation AUC = 0.77 in MAL092; 0.80 in MAL102) as the best-performing univariate model for both studies. The best-performing multivariate predictive model for MAL092 was based on BLI NANP6 Dissociation AUC and ADCP NANP6 (validation AUC = 0.76), and in MAL102, it was based on CSP IgG ELISA, BLI NANP6 Dissociation AUC, and ADCP NANP6 (validation AUC = 0.82). The next approximately 10 highest-ranked models, however, had comparable performance with overlapping 95% CIs, and none were clearly superior to CSP IgG ELISA (validation AUCs 0.74 and 0.71 in MAL092 and MAL102, respectively). Collectively, these findings suggest that the majority of the previously identified candidate CoPs also hold up well in two additional malaria vaccine CHMI trials and underscore the continued utility of the CSP IgG ELISA readout as a robust marker of protection. Further studies are needed to determine whether these candidate CoPs hold in malaria-endemic field settings. Identifying validated CoPs that predict malaria vaccine efficacy would promote the development and approval of more effective and durable next-generation vaccines. These advances could also inform vaccine strategies for other infectious diseases.

Abstract Immunisation system performance depends on effective service delivery and the generation of high-quality data to support planning and decision-making. With the recent scaling down of external health funding, Kenya must identify sustainable strategies to strengthen the resilience of its immunisation programme. We conducted a three-part qualitative study comprising thematic analysis, application of complex adaptive systems (CAS) theory, and the Meadows leverage-points framework. Thematic key personnel interviews were conducted with selected Essential Programme on Immunisation (EPI) personnel from 14 counties and sub-counties in Kenya to explore factors influencing immunisation system performance. Vaccine distribution, health workforce shortages and immunisation financing emerged as the dominant themes affecting immunisation performance. Analysis through a CAS lens revealed that reinforcing feedback loops were more dominant than balancing loops, suggesting that system dysfunctions were more influential than adaptive self-correcting mechanisms, resulting in a tendency toward negative system behaviour. Application of the Meadows framework showed that existing interventions were largely concentrated at lower leverage levels, which are more likely to generate short-term operational improvements, while higher-leverage interventions with the potential for long-term system transformation remained underutilised. We concluded that systems-thinking approaches offer a powerful framework for understanding and improving immunisation system performance. They facilitate the identification of vulnerabilities and bottlenecks, while informing the design of higher-leverage interventions capable of producing sustainable and transformative improvements across the system.

BackgroundModern contraceptive use remains low in many sub-Saharan African countries, including Mozambique, limiting progress towards sexual and reproductive health and Sustainable Development Goals (SDGs). Understanding the prevalence, determinants, and inequalities in modern contraceptive use based on Mozambique-wide national survey is critical to informing effective family planning interventions. MethodWe analyzed the most recent data from the Mozambique Demographic and Health Survey (DHS), 2022-2023, focusing on a total of 11,783 reproductive-aged women (15-49 years). The outcome variable was current use of modern contraceptives. Several individual, household-related and community determinants of modern contraceptives were examined employing multivariable logistic regression. Adjusted odds ratio with corresponding confidence intervals and p-values were reported. Erreygers Concentration Index (ECI) and concentration curves were used to assess wealth-and empowerment-related inequalities. All analyses were conducted on weighted data. ResultOverall, 27.6% of women reported current use of modern contraceptive methods. Younger age, higher education, being employed, higher parity, greater wealth, and a partner with higher education were positively associated with modern contraceptive use. Significant wealth-related (ECI = 0.32, p < 0.001) and womens empowerment-related (ECI = 0.26, p < 0.001) inequalities were observed, indicating that wealthier and more empowered women had higher use of modern contraceptive methods. ConclusionModern contraceptive use in Mozambique is suboptimal and influenced by a combination of individual, household, and contextual factors, with marked socioeconomic and empowerment-related disparities. Policy interventions should focus on improving access to and encouraging use of contraceptives for economically disadvantaged and women with low-empowerment, promoting womens autonomy, enhancing male involvement, and leveraging media and community-based programs to increase awareness and uptake. Equity-focused strategies are essential to achieving national and global family planning targets.

Urogenital schistosomiasis, caused by Schistosoma haematobium, remains a major public health challenge among school-aged children in rural Ghana. Although urogenital indicators are well-established, systemic hepatic biomarker alterations in post-mass drug administration pediatric settings remain poorly characterized. This cross-sectional study evaluated point-of-care urinalysis profiles alongside a panel of serum hepatic and renal biomarkers in 174 children (aged 3 to 16 years) from the Sene West District, Ghana. Active infection (urine microscopy egg detection) was identified in 84 participants (48.3%, median egg count = 4.50 eggs/10 mL, IQR: 1.00 - 9.25). Active infection was strongly associated with microhematuria (57.1% vs. 11.1%, p < 0.001), proteinuria (42.9% vs. 22.2%, p = 0.004), and leukocyturia (27.4% vs. 4.4%, p < 0.001). Children with active infection also demonstrated a higher frequency of composite categorical hepatic biomarker alterations (60.7% vs. 37.8%, p = 0.002), whereas categorical renal alterations showed no significant difference (p = 0.332). Controlling for age and sex, multivariable logistic regression confirmed active infection as a significant independent predictor of composite hepatic biomarker alterations (aOR = 2.54, 95% CI: 1.37 - 4.69, p = 0.003), but not renal alterations (aOR = 1.40, p = 0.359). Continuous medians for individual serum biomarkers showed no significant differences between groups. Combining composite hepatic biomarker thresholds with routine dipstick screening improves the detection of subclinical morbidity in pediatric field settings.

Geocoded health facility data are essential for spatial analyses, yet routine health information systems in many low- and middle-income countries often contain inaccurate, incomplete, inconsistent, or outdated facility coordinates. For Greater Accra, Ghana, we created a geocoded health facility dataset aligned with routine maternal health service data from the District Health Information Management System (DHIMS2). We undertook a desk-based, multi-source geocoding and verification workflow of 602 facilities reporting maternal health services between 2020 and 2024. Candidate coordinates were triangulated using national facility records, online mapping platforms, facility websites and social media, directories, photographs, satellite imagery, and local expert knowledge. Coordinates were classified according to the strength and concordance of supporting evidence, with uncertain cases undergoing secondary review. Coordinates were identified for 96.4% of 602 health facilities (n = 580), with 59.3% assigned a high confidence classification (n = 357). Only 22 facilities (3.7%) could not be located with sufficient supporting evidence. Our resulting dataset is made available in a version-controlled openly-modifiable repository for long-term use, permitting routine service utilisation data to be linked with facility locations; thereby facilitating spatial analysis important for equitable health service planning. By documenting our process, this study makes a typically hidden stage of spatial health research transparent and reproducible. Our findings also highlight the need to treat geocoded facility datasets as living, maintainable geospatial health data infrastructure rather than as static research outputs.