Kamala Thriemer

• MD, MPH, PhD
• Menzies School of Health Research

Plasmodium vivax malaria remains a major challenge in the Asia–Pacific region, where National Malaria Programmes (NMPs) will need to determine optimal radical cure strategies given the availability of novel options, such as high-dose primaquine and tafenoquine. The Options Assessment Toolkit (OAT) was developed to assist NMPs to make decisions on t...

Background Low dose primaquine regimens are widely used to treat Plasmodium vivax malaria, but they have limited efficacy and effectiveness. Short courses with higher daily doses as well as single dose tafenoquine have the potential to improve effectiveness but can increase the risk of adverse events. A clinical review visit on day 3 post-treatment...

Introduction Data on morbidity, mortality and cost for malaria-related hospitalisation are important for prioritising resources for malaria control strategies, but these data are often limited. The aim of this study was to understand the current malaria service delivery in Indonesia, including referral rates to hospitals, mortality outcomes and mal...

Background Community health workers have been key to improvements in global health. In Cambodia, a malaria-endemic country, village malaria workers (VMWs) have helped reduce the malaria burden over the last two decades. In 2021, VMWs were tasked to support health facility workers (HFWs) in conducting follow-up of patients with Plasmodium vivax mala...

Background Researchers acknowledge the need to share study results with the patients and their communities, but this is not done consistently due to a plethora of barriers, including a paucity of data to guide best practice approaches in different populations. Methods This study was nested within a large multi-center randomized controlled trial of...

Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the main risk factor for severe haemolysis following treatment with 8-aminoquinolines (8AQ). The World Health Organization recommends G6PD testing prior to 8AQ-based hypnozoitocidal treatment. Methods We undertook an individual level meta-analysis of the performance of commercially...

Background Disseminating research findings to study participants is emerging as a critical component of clinical research. There is evidence that dissemination strengthens social relations and understanding between researchers and participants and their communities, and it is increasingly required by funding bodies. However, there is limited fundin...

Background As a widely accepted field standard diagnostic tool for malaria, microscopic examination is often difficult to perform in resource-poor settings. The immunochromatographic HRP2/pLDH (Pf/Pan) Rapid Diagnostic Tests (RDTs) serve as alternatives to microscopic examination for falciparum and non-falciparum malaria in co-endemic areas by dete...

Background In moderate-to-high malaria transmission regions, the World Health Organization recommends intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) alongside insecticide-treated bed nets to reduce the adverse consequences of pregnancy-associated malaria. Due to high-grade Plasmodium falciparum resistance...

Background The 8-aminoquinolines, primaquine and tafenoquine, are the only available drugs for the radical cure of Plasmodium vivax hypnozoites. Previous evidence suggests that there is dose-dependent 8-aminoquinoline induced methaemoglobinaemia and that higher methaemoglobin concentrations are associated with a lower risk of P. vivax recurrence. W...

Background Primaquine, the only widely available treatment to prevent relapsing Plasmodium vivax malaria, is produced as 15 mg tablets, and new paediatric formulations are being developed. To inform the optimal primaquine dosing regimen for children, we aimed to determine the efficacy and safety of different primaquine dose strategies in children y...

Plasmodium vivax remains a challenge for malaria elimination since it forms dormant liver stages (hypnozoites) that can reactivate after initial infection. 8-aminoquinolone drugs kill hypnozoites but can cause severe hemolysis in individuals with Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency. The STANDARD G6PD test (Biosensor) is a novel poin...

Productivity losses are often included in costing studies and economic evaluations to provide a comprehensive understanding of the economic burden of disease. Global guidance on estimating productivity losses is sparse, especially for low-and middle-income countries (LMICs) where informal and unpaid work remains dominant. This study aims to describ...

Designing policy in public health is a complex process requiring decision making that incorporates available evidence and is suitable to a country’s epidemiological and health system context. The main objective of this study was to develop an options assessment toolkit (OAT) to provide a pragmatic and evidence-based approach to the development of p...

Background The 8-aminoquinolines, primaquine and tafenoquine, are the only available drugs for the radical cure of Plasmodium vivax hypnozoites. Prior evidence suggests that there is dose-dependent 8-aminoquinoline induced methaemoglobinaemia and that higher methaemoglobin concentrations are associated with a lower risk of P. vivax recurrence. We u...

Background The WHO recommends routine testing of G6PD activity to guide radical cure in patients with Plasmodium vivax malaria. Females may have intermediate G6PD enzyme activity and to date, only complex diagnostics are able to reliably identify them. The semi-quantitative G6PD diagnostic “One Step G6PD Test” (Humasis, RoK; “RDT”) is a lateral flo...

Health policy processes should be evidence-informed, transparent and timely, but these processes are often unclear to stakeholders outside the immediate policymaking environment. We spoke to 36 international malaria stakeholders to gain insights on the processes involved in the World Health Organization’s Global Malaria Programme’s recommendations...

Background Plasmodium vivax remains a major challenge for malaria control and elimination due to its ability to cause relapsing illness. To prevent relapses the Indian National Center for Vector Borne Diseases Control (NCVBDC) recommends treatment with primaquine at a dose of 0.25 mg/kg/day provided over 14 days. Shorter treatment courses may impro...

Introduction Designing policy in public health is a complex process requiring decision making that incorporates available evidence and is suitable to a country’s epidemiological and health system context. The main objective of this study was to develop an options assessment toolkit (OAT) to provide a pragmatic and evidence-based approach to the dev...

In remote communities, diagnosis of G6PD deficiency is challenging. We assessed the impact of modified test procedures and delayed testing for the point-of-care diagnostic STANDARD G6PD (SDBiosensor, RoK), and evaluated recommended cut-offs. We tested capillary blood from fingerpricks (Standard Method) and a microtainer (BD, USA; Method 1), venous...

Background The optimal dosing of primaquine to prevent relapsing Plasmodium vivax malaria in South Asia remains unclear. We investigated the efficacy and safety of different primaquine regimens to prevent P. vivax relapse. Methods A systematic review identified P. vivax efficacy studies from South Asia published between 1 January 2000 and 23 Augus...

Background In areas co-endemic for Plasmodium vivax and Plasmodium falciparum there is an increased risk of P vivax parasitaemia following P falciparum malaria. Radical cure is currently only recommended for patients presenting with P vivax malaria. Expanding the indication for radical cure to patients presenting with P falciparum malaria could red...

Half of all pregnancies at risk of malaria worldwide occur in the Asia-Pacific region, where Plasmodium falciparum and Plasmodium vivax co-exist. Despite substantial reductions in transmission, malaria remains an important cause of adverse health outcomes for mothers and offspring, including pre-eclampsia. Malaria transmission is heterogeneous, and...

Background

Background The World Health Organization recommends that primaquine should be given once weekly for 8-weeks to patients with Plasmodium vivax malaria and glucose-6-phosphate dehydrogenase (G6PD) deficiency, but data on its antirelapse efficacy and safety are limited. Methods Within the context of a multicentre, randomised clinical trial of two pri...

Results-sharing with participants or their communities after the completion of research is an essential element of ethical research. The main objective of this study was to identify and document current practice of trial result dissemination, to explore attitudes among trialists towards result dissemination and to better understand previous experie...

Introduction Symptoms reported following the administration of investigational drugs play an important role in decisions for registration and treatment guidelines. However, symptoms are subjective, and interview methods to quantify them are difficult to standardise. We explored differences in symptom reporting across study sites of a multicentre an...

Background Primaquine is used to eliminate Plasmodium vivax hypnozoites, but its optimal dosing regimen remains unclear. We undertook a systematic review and individual patient data meta-analysis to investigate the efficacy and tolerability of different primaquine dosing regimens to prevent P vivax recurrence. Methods For this systematic review an...

Background Primaquine radical cure is used to treat dormant liver-stage parasites and prevent relapsing Plasmodium vivax malaria but is limited by concerns of haemolysis. We undertook a systematic review and individual patient data meta-analysis to investigate the haematological safety of different primaquine regimens for P vivax radical cure. Met...

Primaquine (PQ) kills Plasmodium vivax hypnozoites but can cause severe hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We conducted two systematic reviews. The first used data from clinical trials to determine the variety of definitions and frequency of hematological serious adverse events (SAEs) related to PQ treat...

Background: Reducing the risk of recurrent Plasmodium vivax malaria is critical for malaria control and elimination. Primaquine (PQ) is the only widely available drug against P. vivax dormant liver stages, but is recommended as a 14-day regimen, which can undermine adherence to a complete course of treatment. Methods: This is a mixed-methods stu...

Plasmodium vivax malaria continues to cause a significant burden of disease in the Asia-Pacific, the Horn of Africa, and the Americas. In addition to schizontocidal treatment, the 8-aminoquinoline drugs are crucial for the complete removal of the parasite from the human host (radical cure). While well tolerated in most recipients, 8-aminoquinolines...

Introduction Recent advances in G6PD deficiency screening and treatment are rapidly changing the landscape of radical cure of vivax malaria available for National Malaria Programs (NMPs). While NMPs await the WHO’s global policy guidance on these advances, they will also need to consider different contextual factors related to the vivax burden, hea...

Background Primaquine (PQ) kills Plasmodium vivax hypnozoites but can cause haemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Methods We did two systematic reviews: the first used data from clinical trials to determine the spectrum of definitions and frequency of haematological serious adverse events (SAE) related to...

Background: The COVID-19 pandemic and resulting restrictions, particularly travel restrictions, have had significant impact on the conduct of global clinical trials. Our clinical trials programme, which relied on in-person visits for training, monitoring and capacity building across nine low- and middle-income countries, had to adapt to those unpr...

Traditionally, patient travel history has been used to distinguish imported from autochthonous malaria cases, but the dormant liver stages of Plasmodium vivax confound this approach. Molecular tools offer an alternative method to identify, and map imported cases. Using machine learning approaches incorporating hierarchical fixation index and decisi...

Background Quantitative measurement of Glucose-6-Phosphate Dehydrogenase (G6PD) enzyme activity is critical to decide on appropriate treatment and provision of radical cure regimens for vivax malaria. Biosensors are point-of-care semi-quantitative analysers that measure G6PD enzyme activity. The main objective of this study was to evaluate the oper...

Background: Elimination targets for Plasmodium vivax are approaching, wit the Cambodian target of 2025. Quantitative tools can assess if proposed strategies are likely to be sufficient to meet those targets. Methods: We calibrated the Optima Malaria transmission model to reported case data from 2011–2018 for six provinces with different transmissi...

Background. Reducing the risk of recurrent P. vivax malaria is critical for malaria control and elimination. Primaquine (PQ) is the only widely available drug against P. vivax dormant liver stages, but is recommended as a 14-day regimen, which can undermine adherence to a complete course of treatment. Methods. This is a mixed-methods study to asses...

Background: Plasmodium vivax forms dormant liver stages that can reactivate weeks or months following an acute infection. Recurrent infections are often associated with a febrile illness and can cause a cumulative risk of severe anaemia, direct and indirect mortality, and onward transmission of the parasite. There is an increased risk of P. vivax...

Primaquine and tafenoquine are the only licensed drugs with activity against Plasmodium vivax hypnozoites but cause haemolysis in patients with glucose–6–phosphate dehydrogenase (G6PD) deficiency. Malaria also causes haemolysis, leading to the replacement of older erythrocytes with low G6PD activity by reticulocytes and young erythrocytes with high...

Primaquine and tafenoquine are the only licensed drugs with activity against Plasmodium vivax hypnozoites but cause haemolysis in patients with glucose-6-phosphate dehydroge-nase (G6PD) deficiency. Malaria also causes haemolysis, leading to the replacement of older erythrocytes with low G6PD activity by reticulocytes and young erythrocytes with hig...

This report describes the MalariaGEN Pv4 dataset, a new release of curated genome variation data on 1,895 samples of Plasmodium vivax collected at 88 worldwide locations between 2001 and 2017. It includes 1,370 new samples contributed by MalariaGEN and VivaxGEN partner studies in addition to previously published samples from these and other sources...

International regulatory authorities and funders require that research be disseminated promptly and appropriately to all involved stakeholders. However, following completion of clinical trials participants often either do not receive any feedback or materials provided are not appropriate for the context. The investigators of a multicentre anti-mala...

Background The changing global health landscape has highlighted the need for more proactive, efficient and transparent health policy-making. After more than 60 years of limited development, novel tools for vivax malaria are finally available, but need to be integrated into national policies. This paper maps the malaria policy-making processes in se...

Background There is a high risk of Plasmodium vivax recurrence in patients treated for Plasmodium falciparum malaria in co-endemic areas. Primaquine radical cure has the potential to reduce P vivax recurrences in patients presenting with P falciparum as well as P vivax malaria but is undermined by poor adherence to the currently recommended 14-day...

Background The radical cure of Plasmodium vivax requires treatment with an 8-aminoquinoline drug, such as primaquine and tafenoquine, to eradicate liver hypnozoite stages, which can reactivate to cause relapsing infections. Safe treatment regimens require prior screening of patients for glucose-6-phosphate dehydrogenase (G6PD) deficiency to avoid p...

Background Glucose-6-phosphate dehydrogenase (G6PD) activity is dependent upon G6PD genotype and age of the red blood cell (RBC) population, with younger RBCs having higher activity. Peripheral parasitemia with Plasmodium spp. induces hemolysis, replacing older RBCs with younger cells with higher G6PD activity. This study aimed to assess whether G6...

In this review for the Vivax malaria collection, Kamala Thriemer and colleagues explore efforts to eliminate P. vivax malaria.

PhD study on stakeholder networks, policy processes and contextual factors influencing P. vivax policy making in three countries.

New diagnostics and treatment options for the radical cure of Plasmodium vivax malaria are now available. At the 2019 annual meeting of the Vivax Working Group of the Asia Pacific Malaria Elimination Network, participants took part in a roundtable discussion to identify further evidence required to introduce these new tools into policy and practice...

Malaria elimination in the Greater Mekong Sub-Region is challenged by a rising proportion of malaria attributable to P. vivax. Primaquine (PQ) is effective in eliminating the parasite’s dormant liver stages and can prevent relapsing infections, but it induces severe haemolysis in patients with Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency, hi...

International regulatory authorities and funders require that research be disseminated promptly and appropriately to all involved stakeholders. However, following completion of clinical trials participants often either do not receive any feedback or materials provided are not appropriate for the context. The investigators of a multicentre anti-mala...

Background There is a high risk of Plasmodium vivax parasitaemia following treatment of falciparum malaria. Our study aimed to quantify this risk and the associated determinants using an individual patient data meta-analysis in order to identify populations in which a policy of universal radical cure, combining artemisinin-based combination therapy...

Background: The radical cure of Plasmodium vivax requires treatment with an 8-aminoquinoline drug, such as primaquine and tafenoquine, to clear the liver of parasites which can reactivate to cause relapsing infections. Safe treatment regimens require prior screening of patients for glucose-6-phosphate dehydrogenase (G6PD) deficiency to avoid potent...

Bangladesh has achieved significant progress towards malaria elimination, although health service delivery for malaria remains challenging in remote forested areas such as the Chittagong Hill Tracts (CHT). The aim of this study was to investigate perceptions of malaria and its treatment among the local population to inform contextualized strategies...

The proportion of Plasmodium vivax malaria among all malarias is increasing worldwide. Treatment with 8-aminoquinolines remain the only radical cure. However, 8-aminoquinolines can cause severe hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients. The population of the multi-ethnic Chittagong Hill Tracts (CHT) carry the highest...

Plasmodium vivax is an important cause of malaria, associated with a significant public health burden. Whilst enhanced malaria-control activities have successfully reduced the incidence of Plasmodium falciparum malaria in many areas, there has been a consistent increase in the proportion of malaria due to P. vivax in regions where both parasites co...

Objective: Electronic data collection (EDC) has become a suitable alternative to paper based data collection (PBDC) in biomedical research even in resource poor settings. During a survey in Nepal, data were collected using both systems and data entry errors compared between both methods. Collected data were checked for completeness, values outside...

Objective: To determine household and health-care provider costs associated with Plasmodium vivax infection across a range of endemic settings. Methods: We collected cost data alongside three multicentre clinical trials of P. vivax treatment in Afghanistan, Brazil, Colombia, Ethiopia, Indonesia, Philippines, Peru, Thailand and Viet Nam conducted b...

We herein report the first case of Mediterranean glucose-6-phosphate dehydrogenase (G6PD) variant from Bangladesh. A boy had been admitted to hospital and was diagnosed with uncomplicated Plasmodium vivax infection and treated with 30 mg/kg body weight (BW) chloroquine for 3 days and 4.8 mg/kg BW primaquine (PQ) to be taken over 14 days. The boy wa...

Background: Antimicrobial resistance (AMR) is a major global health concern, yet, there are noticeable gaps in AMR surveillance data in regions such as sub-Saharan Africa. We aimed to measure the prevalence of extended-spectrum β-lactamase (ESBL) producing Gram-negative bacteria in bloodstream infections from 12 sentinel sites in sub-Saharan Afric...

Background Salmonella Typhimurium and Enteritidis are major causes of bloodstream infection in children in sub-Saharan Africa. This study assessed evidence for their zoonotic versus human reservoir. Methods Index patients were children with blood culture confirmed Salmonella infection recruited during a microbiological surveillance study in Nanoro...

Objective: Electronic data collection (EDC) has become a suitable alternative to paper based data collection (PBDC) in biomedical research even in resource poor settings. During a survey in Nepal, data were collected using both systems and data entry errors compared between both methods. Collected data were checked for completeness, values outside...

Background Artemisinin-based combination therapy (ACT) is recommended for uncomplicated Plasmodium vivax malaria in areas of emerging chloroquine resistance. We undertook a systematic review and individual patient data meta-analysis to compare the efficacies of dihydroartemisinin-piperaquine (DP) and artemether-lumefantrine (AL) with or without pri...

Imported cases present a considerable challenge to the elimination of malaria. Traditionally, patient travel history has been used to identify imported cases, but the long-latency liver stages confound this approach in Plasmodium vivax . Molecular tools to identify and map imported cases offer a more robust approach, that can be combined with drug...

Objective: Electronic data collection (EDC) has become a suitable alternative to paper based data collection (PBDC) in biomedical research even in resource poor settings. During a survey in Nepal, data were collected using both systems and data entry errors compared between both methods. Collected data were checked for completeness, values outside...

Objective: Electronic data collection (EDC) has become a suitable alternative to paper based data collection (PBDC) in biomedical research even in resource poor settings. During a survey in Nepal, data were collected using both systems and data entry errors compared between both methods. Collected data were checked for completeness, values outside...

Objective: Electronic data collection (EDC) has become a suitable alternative to paper based data collection (PBDC) in biomedical research even in resource poor settings. During a survey in Nepal, data were collected using both systems and data entry errors compared between both methods. Collected data were checked for completeness, values outside...

Background: Malaria causes a reduction in haemoglobin that is compounded by primaquine, particularly in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The aim of this study was to determine the relative contributions to red cell loss of malaria and primaquine in patients with uncomplicated Plasmodium vivax. Methods: A systematic...