Use Of Rapid Diagnostic Tests Research Articles

P-2248. Modeling the Economic Impact of Different Testing Strategies for Meningitis/Encephalitis in Adult Patients from a US Hospital Perspective

Abstract Background Meningitis/encephalitis (ME) is a life-threatening disease whose severity and trajectory vary by etiology. Many times, patients with suspected ME are unnecessarily hospitalized and treated with empiric therapy as a precaution while clinicians determine etiology. ME diagnosis and treatment algorithms vary across hospitals, with some using a battery of rapid diagnostic tests (RDTs) or syndromic testing to inform diagnosis and clinical decisions and others relying on bacterial culture and send-out tests. We modeled the economic impact of 4 ME testing strategies from a US hospital perspective. Methods A simulation model was used to generate a large sample of 20,000 suspected ME cases based on known distributions of ME etiology and cerebrospinal fluid (CSF) analysis results. The model simulated diagnosis, clinical decisions, and resource use and costs to hospitals in 4 testing scenarios: (1) no RDTs, (2) a battery of 4 RDTs for HSV, enterovirus, VZV, and C. neoformans/gattii, (3) BIOFIRE® FILMARRAY® ME panel alone [syndromic testing], and (4) syndromic testing in conjunction with RDTs for HSV and C. neoformans/gattii (Figures 1-2). Mean inpatient resource use (i.e., hospital stay and antimicrobial use) and cost per suspected ME case were estimated. Common costs across testing scenarios were excluded. Sensitivity analyses were conducted. Results The mean (95% CI) cost per suspected ME case was estimated at $19,337 ($19,150-$19,525) with no RDT use, $16,412 ($16,226-$16,598) with the battery of 4 RDTs, $15,465 ($15,285-$15,644) with syndromic testing, and $15,720 ($15,536-$15,903) under conjunction testing. Cost savings were driven primarily by reductions in hospital stay due to reduced time to correct pathogen identification. Performance characteristics of RDTs/syndromic test and time to correct pathogen identification had the largest impact on modeled costs for strategies that include RDT/syndromic testing. Conclusion Using either the battery of 4 RDTs or syndromic testing would result in cost savings for hospitals currently not using RDTs in ME diagnosis and treatment. Syndromic testing would yield even higher savings than the battery of 4 RDTs by further reducing unnecessary hospital stays and inappropriate antimicrobial use. Disclosures Rodrigo Hasbun, MD MPH FIDSA, Biomeriaux: Grant/Research Support|Biomeriaux: Honoraria Kyle Hueth, MS, MLS(ASCP)SC, bioMérieux: Stocks/Bonds (Public Company) Glaucia Paranhos-Baccala, PhD, bioMérieux: Stocks/Bonds (Public Company) Tristan T. Timbrook, PharmD, bioMérieux: Stocks/Bonds (Public Company) Lohit Korrapati, MBA, bioMérieux: Advisor/Consultant Catherine Regan, MPH, bioMérieux: Advisor/Consultant Adrienne Kwok, MPH, bioMérieux: Advisor/Consultant Noam Kirson, PhD, bioMérieux: Advisor/Consultant

Magnitude of Potential Biases in COVID-19 Vaccine Effectiveness Studies due to Differential Healthcare seeking following Home Testing: Implications for Test Negative Design Studies.

The test-negative design (TND) is widely used to estimate COVID-19 vaccine effectiveness (VE). Biased estimates of VE may result from effects of at-home SARS-CoV-2 rapid diagnostic test (RDT) results on decisions to seek healthcare. To investigate magnitude of potential bias, we constructed decision trees with input probabilities obtained from longitudinal surveys of U.S. adults between March 2022 - October 2023. Prevalence of at-home RDT use and healthcare seeking following a positive or negative RDT result was estimated by participant vaccination status and socio-demographic characteristics. At true VE values ranging from 5% to 95%, we defined bias as the difference between the observed and true VE . Among 1,918 symptomatic adults, prevalence of at-home RDT use was higher among vaccinated (37%) versus unvaccinated (22%) participants. At-home RDT use was associated with seeking care, and participants reporting positive RDT were more likely than those reporting negative RDT to have sought care when ill. In primary analyses, we observed downward bias in VE estimates that increased in magnitude when true VE was low. Variations in proportions of vaccination, at-home RDT use and healthcare seeking by socio-demographic characteristics may impact VE estimates. Further evaluation of potential impact of at-home RDT use on VE estimates is warranted.

Infectious Risk in Pediatric Emergency Departments in Italy: A Survey by the Italian Society for Pediatric Emergency and Urgent Medicine (SIMEUP) on Available Preventive and Diagnostic Tools.

Background/Objectives: The COVID-19 pandemic has emphasized the importance of preparedness in preventing the spread of infectious diseases, especially in Emergency Departments (EDs), where initial patient assessments and triage occur. This study aims to evaluate the current practices and available tools for infection control in Pediatric EDs across Italy, focusing on the differences between various hospital types and regional settings. Methods: A cross-sectional national survey was conducted in February 2022, targeting healthcare workers in Pediatric EDs across Italy. The survey, distributed via the Italian Society for Pediatric Emergency and Urgent Medicine (SIMEUP) mailing list, collected data on infection control measures, including the availability of hand hygiene stations, personal protective equipment, disinfection protocols, and the use of rapid diagnostic tests. Results: A total of 80 questionnaires were completed from 119 (67.2%) different ERs. The majority of respondents were from Northern Italy (47.5%) and worked in hospitals with 24 h pediatric assistance (48.8%). Less than half of non-pediatric hospitals had separate access for children, potentially exposing them to adult pathogens. Across all settings, basic infection control measures, such as providing masks and hand gel, were widely implemented. However, significant differences were observed in the availability of social distancing, informational materials, and dedicated pediatric pathways, with I level assistance hospitals less likely to have these resources. Rapid diagnostic tests were available in most settings, but the focus was predominantly on SARS-CoV-2, despite other respiratory pathogens' relevance in pediatric care. Conclusions: Strengthening preparations for future pandemics will be crucial in enhancing the resilience of healthcare systems and ensuring the safety of both patients and healthcare workers in the face of emerging infectious threats.

Performance of the Bioline™ Malaria Ag Pf/Pan and Bioline™ Malaria Ag Pf/Pv for Malaria Diagnostics: Madagascar In-Country Evaluation.

Malaria remains a significant public health concern in Madagascar. The WHO recommends using parasitological methods to confirm Plasmodium infection before treatment. This study evaluated the performance of two rapid diagnostic tests (RDTs), Bioline™ Malaria Ag Pf/Pan (Abbott Point of Care, Princeton, NJ) and Bioline™ Malaria Ag Pf/Pv (Abbott Point of Care, Princeton, NJ), compared with microscopy and polymerase chain reaction (PCR) as reference methods. A prospective, diagnostic performance study was conducted in two malaria-endemic districts with different epidemiological contexts: Ifanadiana (Plasmodium falciparum [P. falciparum] transmission) and Mandoto (Plasmodium vivax transmission). Symptomatic patients and asymptomatic individuals aged 3-81 years were enrolled between April and July 2023. Finger prick blood samples were used for RDTs, Giemsa-stained blood films, and molecular analysis. Among 675 participants (401 symptomatic, 274 asymptomatic), the performance for detecting P. falciparum and non-falciparum/vivax malaria in symptomatic patients for Bioline™ Malaria Ag Pf/Pan was 96.5% (95% CI: 93.4-98.4%) and 91.5% (95% CI: 82.5-96.8%) sensitivity and 76.0% (95% CI: 64.7-85.1%) specificity, and the performance for Bioline™ Malaria Ag Pf/Pv was 95.0% and 91.5% sensitivity and 76.0% specificity. In asymptomatic individuals, the performance was 90.3% (95% CI: 83.4-95.0%) and 33.3% (95% CI: 4.3-77.7%) sensitivity and 85.4% (95% CI: 78.9-90.6%) specificity for Bioline™ Malaria Ag Pf/Pan and 80.6% (95% CI: 80.1-93.1%) and 0% (95% CI: 0-84.2%) sensitivity and 86.0% (95% CI: 79.7-91.0%) and 86.1% (95% CI: 79.7-91.0%) specificity for Bioline™ Malaria Ag Pf/Pv. Rapid diagnostic test performance varies with local epidemiology in symptomatic patients. The results emphasize the need for careful consideration of RDT use based on local epidemiology and clinical context. Both RDTs could be used when microscopy and PCR are unavailable.

The spread of molecular markers of artemisinin partial resistance and diagnostic evasion in Eritrea: a retrospective molecular epidemiology study

Eritrea was the first African country to discontinue the use of histidine rich protein 2 (HRP2)-detecting rapid diagnostic tests (RDTs) for malaria diagnosis following reports of a high prevalence of pfhrp2/3-deleted Plasmodium falciparum parasites causing false-negative results in the country. Eritrea was also the first African country to report partial artemisinin resistance due to the Pfalciparum kelch13 (pfk13) Arg622Ile mutation. We aimed tocharacterise the spatial distribution of pfk13 mutants and their interactions with pfhrp2/3 deletions in Eritrea andto assess the role of the use of HRP2-detecting RDTs and antimalarial (artesunate-amodiaquine) therapy in the spread of the two variants. We conducted a retrospective molecular epidemiological analysis of pfk13 mutations and pfhrp2/3 deletions in existing Pfalciparum-infected blood samples collected as part of previous pfhrp2/3 deletion and severe malaria studies. Samples were collected in March, 2016and between September, 2018, and January, 2020, from symptomatic patients seeking care at 15health centres in four administration zones (Semenawi Keyih Bahri, Gash Barka, Anseba, and Debub) in Eritrea. Afragment spanning the propeller region of pfk13 was amplified from samples and sequenced using Sanger sequencing or targeted amplicon sequencing to identify genetic mutations. Deletions of pfhrp2/3 genes in samples were determined using multiplex quantitative PCR. Parasite haplotypes and genetic relatedness of parasite haplotypes were determined previously using microsatellite marker typing. The primary objective was to determine the prevalence of pfk13 mutations at health centres and administrative zones. The secondary objective was to investigate whether pfk13 mutants and pfhrp2/3 deleted parasites converge. We sequenced 50samples collected in March, 2016from the Semenawi Keyih Bahri zone and identified no pfk13 mutations. By contrast, in 587samples included in this study that were collected from health centres in GashBarka, Anseba, and Debub in 2018-20, we detected five different single non-synonymous mutations: Glu605Lys, Arg622Ile, Asn657Lys, Lys658Glu, and Ser679Leu. The most prevalent mutation was pfk13 Arg622Ile, which was detected in samples collected from all nine health centres where more than five samples were available across all three administration zones, with an overall prevalence of 11·9% (70 of 587samples; range 5·9-28·0%). Weidentified 22unique pfk13 Arg622Ile mutant haplotypes among 26samples tested, of which 13 (59·1%) were genetically related, whereas the remaining nine (40·9%) were not. The prevalence of pfk13 Arg622Ile was significantly higher in parasites with a single pfhrp3 deletion (46 [18·0%] of 255samples) than in parasites withoutpfhrp2/3 deletions (ten [6·2%] of 161samples; odds ratio 3·89 [95% CI 1·59-7·61]; p=0·0006) and with dual pfhrp2/3-deleted parasites (13 [9·0%] of 145; 2·23 [1·13-4·68]; p=0·018). The geographical spread of the pfk13 Arg622Ile mutation might have initially resulted from the clonal expansion and spread of pfhrp2/3 deletions under the test-and-treat policy using HRP2-detecting RDTs. Subsequently, selective pressure from artemisinin combination therapy could have further facilitated the spread of both pfk13 Arg622Ile and pfhrp2/3 deletions. Continuous monitoring of trends in pfk13 and pfhrp2/3 variants is needed to inform effective malaria control and elimination strategies in Eritrea and other African countries. US Department of Defense Armed Forces Health Surveillance Division, Global Emerging Infections Surveillance Branch (AFHSD/GEIS), and Wellcome Trust.

Performance of ParaHIT® HRP2-Based Rapid Diagnostic Test and Proportions of Plasmodium falciparum Histidine-Rich Protein 2/3 Gene Deletions in Togo.

In areas where malaria is endemic and microscopes are unavailable, rapid diagnostic tests (RDTs) are essential tools for early diagnosis and prompt and effective treatment. However, HRP2-based RDTs are threatened by the emergence of Plasmodium falciparum parasites that do not carry the pfhrp2 or pfhrp3 gene, leading to false-negative results. Therefore, the aim of this study was to evaluate the performance of the ParaHIT RDT together with the proportion of pfhrp2/3 gene-deleted P. falciparum parasites in Togo. The performance of RDTs compared with microscopy and polymerase chain reaction (PCR) was determined using capillary blood collected by finger prick during a cross-sectional study conducted from September 2021 to January 2022 in children aged 6-59 months at two sentinel sites. Blood spots were collected for molecular analysis. Amplicons from the target regions (exon 2 of hrp2 and hrp3 genes) were generated by multiplex nested PCR and sequenced using Illumina's MiSeq protocol. A total of 278 samples were analyzed for ParaHIT RDT evaluation. The sensitivity and specificity of the RDT test compared with microscopy were 96.4% and 85.7%, respectively, which increased to 97.9% and 90.7%, respectively, when compared with PCR. Of the microscopically and PCR-positive P. falciparum samples, 138 were sequenced to detect pfhrp2/3 deletions. None of the parasites had a single pfhrp2 deletion or a single pfhrp3 deletion. The ParaHIT RDT demonstrated an acceptable level of performance in this evaluation, confirming the use of HRP2-based RDTs for the detection of P. falciparum infection in areas where microscopy is not available in Togo.

Bridging the "know-do" gap to improve active case finding for tuberculosis in India: A qualitative exploration into national tuberculosis elimination program staffs' perspectives.

In 2022, India's national tuberculosis (TB) elimination program (NTEP) commissioned a national level evaluation of active case finding (ACF) for TB to guide evidence-based strategic planning. As part of this evaluation, based on secondary data analysis we observed that the quality of ACF was suboptimal in 2021. Hence, this study aimed to understand the enablers, barriers, and suggested solutions to improve ACF for TB in India from NTEP staff (provider) perspective. This was a descriptive qualitative study involving key informant interviews from six districts and eight states, conducted between February and August 2023. We purposively selected key state- district- and sub-district-level program managers and implementers who were experienced and vocal. The interviews were audio recorded and transcribed verbatim by research interns and investigators. Two investigators independently did manual descriptive thematic analysis, and a third investigator resolved inconsistencies. The themes and categories emerged by collating together the results of the coding process. A total of 34 key informant interviews were conducted and of these, four were repeat interviews. Adequate budgets for ACF including incentives, performance review mechanism, engagement of all stakeholders, adopting a community friendly approach, use of rapid diagnostic tests and digitalization were the perceived enablers. In some states ACF was implemented in general population (not restricted to high-risk population) following directives at state level. There were limited mechanisms to ensure ACF quality indicators were met before disbursing incentives and cross-verification of the aggregate ACF care cascade numbers that were reported in Ni-kshay (electronic TB information management system under NTEP). In addition to the state and district level implementers having limited understanding of concepts around ACF (quality indicators, number needed to screen and yield), we also inferred the presence of a 'know-do' gap for many activities under ACF. The suggested solutions were around capacity building and quality improvement strategies. The existing national ACF guidance should be revised to emphasize capacity building, need to carry out ACF in high-risk (not general) population, quality control-linked incentives, and regular implementation monitoring of the activities. This should contribute towards better coverage and improved quality translating into better ACF outcomes.

Histidine-rich protein (hrp) 2-based RDT false-negatives and Plasmodium falciparum hrp 2 and 3 gene deletions in low, seasonal and intense perennial transmission zones in Cameroon: a cross - sectional study.

False negative rapid diagnostic tests (RDTs) accruing to the non-detection of Plasmodium falciparum histidine-rich protein 2/3 (Pfhrp2/3) is threatening the diagnosis and management of malaria. Although regular monitoring is necessary to gauge the level of efficacy of the tool, studies in Cameroon remain limited. This study assessed Plasmodium spp. prevalence and Pfhrp2/3 gene deletions across ecological and transmission zones in Cameroon. This is a cross-sectional, multi-site, community- and hospital- based study, in 21 health facilities and 14 communities covering all five ecological settings in low seasonal (LS) and intense perennial (IPT) malaria transmission zones between 2019 and 2021. Participants were screened for malaria parasite using Pfhrp2 RDT and light microscopic examination of thick peripheral blood smears. DNA was extracted from dried blood spot using chelex®-100 and P. falciparum confirmed using varATS real-time quantitative Polymerase Chain Reaction (qPCR), P. malariae and P. ovale by real-time qPCR of Plasmepsin gene, and P. vivax using a commercial kit. Isolates with amplified Pfcsp and Pfama-1 genes were assayed for Pfhrp 2/3 gene deletions by conventional PCR. A total of 3,373 participants enrolled, 1,786 Plasmodium spp. infected, with 77.4% P. falciparum. Discordant RDT and qPCR results (False negatives) were reported in 191 (15.7%) P. falciparum mono-infected samples from LS (29%, 42) and IPT (13.9%, 149). The Pfhrp2+/Pfhrp3 + genotype was most frequent, similar between LS (5.5%, 8/145) and IPT (6.0%, 65/1,076). Single Pfhrp2 and Pfhrp3 gene deletions occurred in LS (0.7%, 1/145 each) and IPT (3.6%, 39/1,076 vs. 2.9%, 31/1,076), respectively. Whilst a single sample harboured Pfhrp2-/Pfhrp3- genotype in LS, 2.4% (26/1,076) were double deleted at IPT. Pfhrp2+/Pfhrp3- (0.3%, 3/1,076) and Pfhrp2-/Pfhrp3+ (1.2%, 13/1,076) genotypes were only observed in IPT. Pfhrp2, Pfhrp3 deletions and Pfhrp2-/Pfhrp3- genotype accounted for 78.8% (26), 69.7% (23) and 63.6% (21) RDT false negatives, respectively. Plasmodium falciparum remains the most dominant and widely distributed Plasmodium species across transmission and ecological zones in Cameroon. Although the low prevalence of Pfhrp2/3 gene deletions supports the continued use of HRP2-based RDTs for routine malaria diagnosis, the high proportion of false-negatives due to gene deleted parasites necessitates continued surveillance to inform control and elimination efforts.

Advances in Malaria Diagnostic Methods in Resource-Limited Settings: A Systematic Review.

Malaria continues to pose a health challenge globally, and its elimination has remained a major topic of public health discussions. A key factor in eliminating malaria is the early and accurate detection of the parasite, especially in asymptomatic individuals, and so the importance of enhanced diagnostic methods cannot be overemphasized. This paper reviewed the advances in malaria diagnostic tools and detection methods over recent years. The use of these advanced diagnostics in lower and lower-middle-income countries as compared to advanced economies has been highlighted. Scientific databases such as Google Scholar, PUBMED, and Multidisciplinary Digital Publishing Institute (MDPI), among others, were reviewed. The findings suggest important advancements in malaria detection, ranging from the use of rapid diagnostic tests (RDTs) and molecular-based technologies to advanced non-invasive detection methods and computerized technologies. Molecular tests, RDTs, and computerized tests were also seen to be in use in resource-limited settings. In all, only twenty-one out of a total of eighty (26%) low and lower-middle-income countries showed evidence of the use of modern malaria diagnostic methods. It is imperative for governments and other agencies to direct efforts toward malaria research to upscale progress towards malaria elimination globally, especially in endemic regions, which usually happen to be resource-limited regions.

The use of rapid diagnostic tests for chronic Chagas disease: An expert meeting report.

Chagas disease, caused by Trypanosoma cruzi, affects millions of people globally and is associated with significant underdiagnosis and undertreatment. Current diagnostic algorithms face challenges in remote regions. We aimed to review the potential of rapid diagnostic tests (RDTs) for screening or diagnosing chronic Chagas disease in endemic areas. An expert panel representing scientific and academic institutions from the Americas convened with the aim of discussing the use of RDTs. The study employed the nominal group technique, gathering insights from diverse experts during a 3-day meeting. Panel discussions covered RDT application, research protocols, and regulatory mechanisms. The results indicate that RDTs play a crucial role in surveillance and screening, although limitations in sensitivity and specificity exist. The expert group recommends standardized protocols, emphasizes the importance of cost-effectiveness assessments, and highlights the need to consider geographic validation. Despite these challenges, RDTs present a promising avenue for improving Chagas disease diagnosis in resource-limited settings. Future research and a collaborative approach are deemed essential for effective implementation.

Cost-effectiveness of sentinel screening of endemic diseases alongside malaria diagnosis: A case study in schistosomiasis.

In countries where malaria is endemic, the use of rapid diagnostic tests(RDTs) has become routine, especially in rural settings. Such regions are characterised by often having other co-endemic infectious diseases, at high levels of prevalence. To illustrate the potential added-value of "sentinel" screening for patients presenting for a routine diagnostic test for malaria, at healthcare facilities in Uganda. We developed an economic model by combining two decision trees, one for malaria and a second for the co-endemic disease schistosomiasis. The integrated model was designed to inform policy strategies for the co-endemic disease in addition to malaria (i.e., whether to test opportunistically for schistosomiasis or use mass drug administration(MDA) as per usual practice).We performed the analysis on three comparators varying testing accuracy and costs. Sentinel screening can provide added value to the testing of patients compared with the status quo: when schistosomiasis prevalence is high then MDA is preferential; if low prevalence, treating no one is preferred. If the disease has average levels of prevalence, then a strategy involving testing is preferred. Prevalence thresholds driving the dominant strategy are dependent upon the model parameters, which are highly context specific. At average levels of prevalence for schistosomiasis and malaria for Uganda, adding a sentinel screening was cost-effective when the accuracy of test was higher than current diagnostics and when economies of scope were generated(Expected value clinical Information = 0.65$ per DALY averted, 137.91$ per correct diagnoses).Protocols using diagnostics with current accuracy levels were preferred only for levels of MDA coverage below 75%. The importance of the epidemiological setting is crucial in determining the best cost-effective strategy for detecting endemic disease. Economies of scope can make sentinel screenings cost-effective strategies in specific contexts. Blanket thresholds recommended for MDA may not always be the preferred option for endemic diseases.

Improving malaria case management with artemisinin-based combination therapies and malaria rapid diagnostic tests in private medicine retail outlets in sub-Saharan Africa: A systematic review.

Private medicine retailers (PMRs) such as pharmacies and drug stores account for a substantial share of treatment-seeking for fever and malaria, but there are widespread concerns about quality of care, including inadequate access to malaria rapid diagnostic tests (RDTs) and artemisinin-based combination therapies (ACTs). This review synthesizes evidence on the effectiveness of interventions to improve malaria case management in PMRs in sub-Saharan Africa (PROSPERO #2021:CRD42021253564). We included quantitative studies evaluating interventions supporting RDT and/or ACT sales by PMR staff, with a historical or contemporaneous control group, and outcomes related to care received. We searched Medline Ovid, Embase Ovid, Global Health Ovid, Econlit Ovid and the Cochrane Library; unpublished studies were identified by contacting key informants. We conducted a narrative synthesis by intervention category. We included 41 papers, relating to 34 studies. There was strong evidence that small and large-scale ACT subsidy programmes (without RDTs) increased the market share of quality-assured ACT in PMRs, including among rural and poorer groups, with increases of over 30 percentage points in most settings. Interventions to introduce or enhance RDT use in PMRs led to RDT uptake among febrile clients of over two-thirds and dispensing according to RDT result of over three quarters, though some studies had much poorer results. Introducing Integrated Community Case Management (iCCM) was also effective in improving malaria case management. However, there were no eligible studies on RDT or iCCM implementation at large scale. There was limited evidence that PMR accreditation (without RDTs) increased ACT uptake. Key evidence gaps include evaluations of RDTs and iCCM at large scale, evaluations of interventions including use of digital technologies, and robust studies of accreditation and other broader PMR interventions.

Use of Measles and Rubella Rapid Diagnostic Tests to Improve Case Detection and Targeting of Vaccinations.

Efforts to control and eliminate measles and rubella are aided by high-quality surveillance data-supported by laboratory confirmation-to guide decision-making on routine immunization strategies and locations for conducting preventive supplementary immunization activities (SIAs) and outbreak response. Important developments in rapid diagnostic tests (RDTs) for measles and rubella present new opportunities for the global measles and rubella surveillance program to greatly improve the ability to rapidly detect and respond to outbreaks. Here, we review the status of RDTs for measles and rubella Immunoglobulin M (IgM) testing, as well as ongoing questions and challenges regarding the operational use and deployment of RDTs as part of global measles and rubella surveillance. Efforts to develop IgM RDTs that can be produced at scale are underway. Once validated RDTs are available, clear information on the benefits, challenges, and costs of their implementation will be critical for shaping deployment guidance and informing country plans for sustainably deploying such tests. The wide availability of RDTs could provide new programmatic options for measles and rubella elimination efforts, potentially enabling improvements and flexibility for testing, surveillance, and vaccination.

Molecular detection of sub-microscopic infections and Plasmodium falciparum histidine-rich protein-2 and 3 gene deletions in pre-elimination settings of South Africa

South Africa’s efforts toward eliminating malaria have positioned the country in the pre-elimination stage. Imported and sub-microscopic cases still contribute to the persistence of malaria in regions of low transmission as identified in this study where diagnostics is built largely on the use of Rapid Diagnostic Test (RDT). However, the presence of Pfhrp2/3 gene deletion is known to interfere with the accuracy of diagnosis with the use of RDT. Malaria elimination and detection of Pfhrp2/3 gene deletion in the pre-elimination setting requires accurate molecular surveillance. With the core objective of this study being the determination of the presence sub-microscopic malaria cases and deleted Pfhrp2/3 gene markers, a total of 354 samples were collected from five districts of KwaZulu Natal, South Africa. These samples were prepared for molecular analysis using primers and PCR conditions specific for amplification of 18S rRNA and msp-1gene. Positive amplicons were analysed for the presence of Pfhrp2/3 and flanking genes, along with Sanger sequencing and phylogenetic studies. Out of 354 samples collected 339 were tested negative with PfHRP2 based RDTs. Of these Pfhrp2 and Pfhrp3 gene deletions were confirmed in 94.7% (18/19) and 100% (19/19) respectively. High migration rate (75%) among the study participants was noted and phylogenetic analysis of sequenced isolates showed close evolutionary relatedness with India, United Kingdom, Iran, and Myanmar and China isolates. Molecular-based test is recommended as an essential surveillance tool for malaria management programs as the target focuses on elimination.

Cost-Effectiveness of Test-and-Treat Strategies to Reduce the Antibiotic Prescription Rate for Acute Febrile Illness in Primary Healthcare Clinics in Africa.

Inappropriate antibiotic use increases selective pressure, contributing to antimicrobial resistance. Point-of-care rapid diagnostic tests (RDTs) would be instrumental to better target antibiotic prescriptions, but widespread implementation of diagnostics for improved management of febrile illnesses is limited. Our study aims to contribute to evidence-based guidance to inform policymakers on investment decisions regarding interventions that foster more appropriate antibiotic prescriptions, as well as to address the evidence gap on the potential clinical and economic impact of RDTs on antibiotic prescription. A country-based cost-effectiveness model was developed for Burkina Faso, Ghana and Uganda. The decision tree model simulated seven test strategies for patients with febrile illness to assess the effect of different RDT combinations on antibiotic prescription rate (APR), costs and clinical outcomes. The incremental cost-effectiveness ratio (ICER) was expressed as the incremental cost per percentage point (ppt) reduction in APR. For Burkina Faso and Uganda, testing all patients with a malaria RDT was dominant compared to standard-of-care (SoC) (which included malaria testing). Expanding the test panel with a C-reactive protein (CRP) test resulted in an ICER of $0.03 and $0.08 per ppt reduction in APR for Burkina Faso and Uganda, respectively. For Ghana, the pairwise comparison with SoC-including malaria and complete blood count testing-indicates that both testing with malaria RDT only and malaria RDT + CRP are dominant. The use of RDTs for patients with febrile illness could effectively reduce APR at minimal additional costs, provided diagnostic algorithms are adhered to. Complementing SoC with CRP testing may increase clinicians' confidence in prescribing decisions and is a favourable strategy.

Rapid Diagnostic Tests and Antimicrobial Stewardship Programs for the Management of Bloodstream Infection: What Is Their Relative Contribution to Improving Clinical Outcomes? A Systematic Review and Network Meta-analysis.

Evidence about the clinical impact of rapid diagnostic tests (RDTs) for the diagnosis of bloodstream infections is limited, and whether RDT are superior to conventional blood cultures (BCs) embedded within antimicrobial stewardship programs (ASPs) is unknown. We performed network meta-analyses using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT (applied on positive BC broth or whole blood) to conventional BC, both assessed with and without ASP with respect to mortality, length of stay (LOS), and time to optimal therapy. Eighty-eight papers were selected, including 25 682 patient encounters. There was an appreciable amount of statistical heterogeneity within each meta-analysis. The network meta-analyses showed a significant reduction in mortality associated with the use of RDT + ASP versus BC alone (odds ratio [OR], 0.72; 95% confidence interval [CI], .59-.87) and with the use of RDT + ASP versus BC + ASP (OR, 0.78; 95% CI, .63-.96). No benefit in survival was found associated with the use of RDT alone nor with BC + ASP compared to BC alone. A reduction in LOS was associated with RDT + ASP versus BC alone (OR, 0.91; 95% CI, .84-.98) whereas no difference in LOS was shown between any other groups. A reduced time to optimal therapy was shown when RDT + ASP was compared to BC alone (-29 hours; 95% CI, -35 to -23), BC + ASP (-18 hours; 95% CI, -27 to -10), and to RDT alone (-12 hours; 95% CI, -20 to -3). The use of RDT + ASP may lead to a survival benefit even when introduced in settings already adopting effective ASP in association with conventional BC.

A qualitative study on determinants of the use of malaria rapid diagnostic test and anti-malarial drug prescription practices by primary healthcare workers in Ebonyi state, Nigeria

BackgroundThe increased availability and use of malaria rapid diagnostic test (RDT) by primary healthcare (PHC) workers has made universal diagnostic testing before malaria treatment more feasible. However, to meaningfully resolve the problem of over-treatment with artemisinin-based combination therapy and the heightened risk of selection pressure and drug resistance, there should be appropriate response (non-prescription of anti-malarial drugs) following a negative RDT result by PHC workers. This study explored the determinants of the use of RDT and anti-malarial drug prescription practices by PHC workers in Ebonyi state, Nigeria.MethodsBetween March 2 and 10, 2020, three focus group discussions were conducted in English with 23 purposively-selected consenting PHC workers involved in the diagnosis and treatment of malaria. Data was analysed thematically as informed by the method by Braun and Clarke.ResultsThe determinants of the use of RDT for malaria diagnosis were systemic (RDT availability and patient load), provider related (confidence in RDT and the desire to make correct diagnosis, PHC worker’s knowledge and training, and fear to prick a patient), client related (fear of needle prick and refusal to receive RDT, and self-diagnosis of malaria, based on symptoms, and insistence on not receiving RDT), and RDT-related (the ease of conducting and interpreting RDT). The determinants of anti-malarial drug prescription practices were systemic (drug availability and cost) and drug related (effectiveness and side-effects of the drugs). The determinants of the prescription of anti-malarial drugs following negative RDT were provider related (the desire to make more money and limited confidence in RDT) and clients’ demand while unnecessary co-prescription of antibiotics with anti-malarial drugs following positive RDT was determined by the desire to make more money.ConclusionsThis evidence highlights many systemic, provider, client, and RDT/drug related determinants of PHC workers’ use of RDT and anti-malarial drug prescription practices that should provide tailored guidance for relevant health policy actions in Ebonyi state, Nigeria, and similar settings.

A measles IgM rapid diagnostic test to address challenges with national measles surveillance and response in Malaysia.

A lateral flow rapid diagnostic test (RDT) enables detection of measles specific immunoglobulin M (IgM) antibody in serum, capillary blood, and oral fluid with accuracy consistent with enzyme immunoassay (EIA). The objectives of the study were: 1) to assess measles RDT inter-reader agreement between two clinic staff; 2) to assess the sensitivity and specificity of the measles RDT relative to standard surveillance testing in a low transmission setting; 3) to evaluate the knowledge, attitudes, and practices of staff in clinics using the RDT; and 4) to assess the impact of RDT testing on the measles public health response in Malaysia. The clinic-based prospective evaluation included all suspected measles cases captured by routine measles surveillance at 34 purposely selected clinics in 15 health districts in Malaysia between September 2019 and June 2020, following day-long regional trainings on RDT use. Following informed consent, four specimens were collected from each suspected case, including those routinely collected for standard surveillance [serum for EIA and throat swabs for quantitative reverse transcriptase polymerase chain reaction (RT-qPCR)] together with capillary blood and oral fluid tested with RDTs during the study. RDT impact was evaluated by comparing the rapidity of measles public health response between the pre-RDT implementation (December 2018 to August 2019) and RDT implementation periods (September 2019 to June 2020). To assess knowledge, attitudes, and practices of RDT use, staff involved in the public health management of measles at the selected sites were surveyed. Among the 436 suspect cases, agreement of direct visual readings of measles RDT devices between two health clinic staff was 99% for capillary blood (k = 0.94) and 97% for oral fluid (k = 0.90) specimens. Of the total, 45 (10%) were positive by measles IgM EIA (n = 44, including five also positive by RT-qPCR) or RT-qPCR only (n = 1), and 38 were positive by RDT (using either capillary blood or oral fluid). Using measles IgM EIA or RT-qPCR as reference, RDT sensitivity using capillary blood was 43% (95% CI: 30%-58%) and specificity was 98% (95% CI: 96%-99%); using oral fluid, sensitivity (26%, 95% CI: 15%-40%) and specificity (97%, 95% CI: 94%-98%) were lower. Nine months after training, RDT knowledge was high among staff involved with the public health management of measles (average quiz score of 80%) and was highest among those who received formal training (88%), followed by those trained during supervisory visits (83%). During the RDT implementation period, the number of days from case confirmation until initiation of public response decreased by about 5 days. The measles IgM RDT shows >95% inter-reader agreement, high retention of RDT knowledge, and a more rapid public health response. However, despite ≥95% RDT specificity using capillary blood or oral fluid, RDT sensitivity was <45%. Higher-powered studies using highly specific IgM assays and systematic RT-qPCR for case confirmation are needed to establish the role of RDT in measles elimination settings.

Evaluation of the Performance of Rapid Diagnostic Tests for Malaria Diagnosis and Mapping of Different Plasmodium Species in Mali.

The first-line diagnosis of malaria in Mali is based on the use of rapid diagnostic tests (RDT) that detect the Histidin Rich Protein 2 (HRP2) antigen specific to Plasmodium falciparum. Our study, based on a real-time polymerase chain reaction (qPCR) gold standard, aimed to describe the distribution of the Plasmodium species in each administrative region of Mali and to assess the performance of RDTs. We randomly selected 150 malaria-negative and up to 30 malaria-positive RDTs in 41 sites distributed in 9 regions of Mali. DNA extracted from the RDT nitrocellulose strip was assayed with a pan-Plasmodium qPCR. Positive samples were then analyzed with P. falciparum-, P. malariae-, P. vivax-, or P. ovale-specific qPCRs. Of the 1496 RDTs, 258 (18.6%) were positive for Plasmodium spp., of which 96.9% were P. falciparum. The P. vivax prevalence reached 21.1% in the north. RDT displayed acceptable diagnostic indices; the lower CI95% bounds of Youden indices were all ≥0.50, except in the north (Youden index 0.66 (95% CI [0.44-0.82]) and 0.63 (95% CI [0.33-0.83]. Overall, RDT diagnostic indices are adequate for the biological diagnosis of malaria in Mali. We recommend the use of RDTs detecting P. vivax-specific antigens in the north.

Rapid Detection of M. tuberculosis and Its Resistance to Rifampicin and Isoniazid with the mfloDx™ MDR-TB test.

Rapid detection of tuberculosis (TB) and its resistance are essential for the prompt initiation of correct drug therapy and for stopping the spread of drug-resistant TB. There is an urgent need for increased use of rapid diagnostic tests to control the threat of increased TB and multidrug-resistant TB (MDR-TB). EMPE Diagnostics has developed a multiplex molecular diagnostic platform called mfloDx™ by combining nucleotide-specific padlock probe-dependent rolling circle amplification with sensitive lateral flow biosensors, providing visual signals, similar to a COVID-19 test. The first test kit of this platform, mfloDx™ MDR-TB can identify Mycobacterium tuberculosis (MTB) complex and its clinically significant mutations in the rpoB and katG genes and in the inhA promotor contributing resistance to rifampicin (RIF) and isoniazid (INH), causing MDR-TB. We have evaluated the performance of the mfloDx™ MDR-TB test on 210 sputum samples (110 from suspected TB cases and 100 from TB-negative controls) received from a tertiary care center in India. The clinical sensitivity for detecting MTB compared to acid-fast microscopy and mycobacteria growth indicator tube (MGIT) cultures was 86.4% and 84.9%, respectively. All the 100 control samples were negative indicating excellent specificity. In smear-positive sputum samples, the mfloDx™ MDR-TB test showed a sensitivity of 92.5% and 86.4% against MGIT culture and Xpert MTB/RIF, respectively. The clinical sensitivity for the detection of RIF and INH resistance in comparison with MGIT drug susceptibility testing was 100% and 84.6%, respectively, while the clinical specificity was 100%. From the above evaluation, we find mfloDx™ MDR-TB to be a rapid and efficient test to detect TB and its multidrug resistance in 3 h at a low cost making it suitable for resource-limited laboratories.