Blood Spots Research Articles

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.

Monitoring SARS-CoV-2 IgA, IgM and IgG antibodies in dried blood and saliva samples using antibody proximity extension assays (AbPEA)

Using a modified proximity extension assay, total and immunoglobulin (Ig) class-specific anti-SARS-CoV-2 antibodies were sensitively and conveniently detected directly from ø1.2 mm discs cut from dried blood and saliva spots (DBS and DSS) without the need for elution. For total Ig detection, antigen probes were prepared by conjugating recombinant spike protein subunit 1 (S1-RBD) to a pair of oligonucleotides. To detect isotype-specific antibody reactivity, one antigen probe was replaced with oligonucleotide-conjugated antibodies specific for antibody isotypes. Binding of pairs of oligonucleotide-conjugated probes to antibodies in patient samples brings oligonucleotides in proximity. An added DNA polymerase uses a transient hybridization between the oligonucleotides to prime synthesis of a DNA strand, which serves as a DNA amplicon that is quantified by real-time PCR. The S1-RBD-specific IgG, IgM, and IgA antibodies in DBS samples collected over the course of a first and second vaccination exhibited kinetics consistent with previous reports. Both DBS and DSS collected from 42 individuals in the autumn of 2023 showed significant level of total S1-RBD antibodies with a correlation of R = 0.70. However, levels in DSS were generally 10 to 100-fold lower than in DBS. Anti-S1-RBD IgG and IgA in DSS demonstrated a correlation of R = 0.6.

Therapeutic efficacy of artemether–lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria in Arba Minch Zuria District, Gamo Zone, Southwest Ethiopia

BackgroundArtemether–lumefantrine (AL) has been the primary anti-malarial drug used to treat uncomplicated Plasmodium falciparum malaria in Ethiopia since 2004. However, there have been recent reports of AL resistance mutations in different African countries, including Ethiopia. This is concerning and requires periodic monitoring of anti-malarial drug resistance. Therefore, the current study aimed to evaluate the therapeutic efficacy of AL in treating uncomplicated P. falciparum malaria in the Arba Minch Zuria District, Gamo Zone, Southwest Ethiopia.MethodsA single-arm prospective study with a 28-day follow-up period was conducted from July to October 2022. Capillary blood samples were collected for RDT and microscopic examination. The study enrolled monoinfected P. falciparum patients aged ≥ 18 years at Ganta Sira Health Post. Sociodemographic and clinical data were recorded, and a dried blood spot (DBS) was prepared for each participant. Nested polymerase chain reaction (nPCR) genotyping of the msp-1 and msp-2 genes was only performed for recurrent cases to distinguish between recurrence and reinfection. Data entry and analysis were performed using the WHO Excel spreadsheet and SPSS version 26.ResultsA total of 89 patients were enrolled, and 67 adequately completed the 28-day follow-up period. AL showed a 100% clearance rate for fever on day 2 and asexual parasites on day 3. Gametocytes were detected in 13.5% (12/89) of the participants. The gametocyte clearance rate was 58.3% (7/12) until day 7 and 100% (12/12) until day 14. Five participants developed recurrent malaria, three of whom experienced relapse and two of whom experienced reinfection. Based on the Kaplan–Meier survival analysis, the PCR-uncorrected and PCR-corrected cumulative incidence of success were 93.7% (95% CI 85.5–97.3) and 96.2% (95% CI 85.5–98.7), respectively.ConclusionAL was efficacious in treating uncomplicated P. falciparum malaria in the study area. However, the detection of recurrent patients highlights the need for continuous efficacy studies in this area.

A cross-sectional analysis identifies a low prevalence of Plasmodium ovale species infections in symptomatic and asymptomatic individuals in Kilifi county, Kenya.

Background The focus on P. falciparum diagnosis has led to an underestimation of the global burden of malaria resulting from neglected Plasmodium species. However, there is still scarce data on the prevalence of P. ovale species (spp) globally. To address this knowledge gap, data collected from cross-sectional studies in Kilifi county were used to: 1) determine the prevalence of P. ovale spp infections; and 2) determine the sensitivity of different diagnostic assays in detecting P. ovale spp infections. Methods A total of 531 individuals were sampled across three study sites in Kilifi County, Kenya between 2009 and 2020. Blood smears were prepared from peripheral blood and screened for Plasmodium parasite stages using light microscopy. Molecular screening involved DNA extraction of dried blood spots and blood in ethylenediaminetetraacetic acid, polymerase chain reaction (PCR) using primers targeting the 18 small ribosomal subunit and sequencing. Results Microscopy screening revealed that the most prevalent species was P. falciparum (32.0%) followed by P. malariae (9.0%) and then P. ovale spp( 1.5%). PCR screening identified additional P. ovale spp positives cases. Overall PCR results indicate that43 (8.1%) out of the 531 individuals harbored P. ovale spp infection with the highest prevalence reported in the tertiary health facility, (14.6%, 95% CI 8-23.6%), followed by the primary health facility (8.3%, 95% CI 5.4-11.9%), and the community from a cross-sectional blood survey, (3.6%, 95% CI 1.2-8.2%). Microscopy screening for P. ovale spp had a low sensitivity of 7% (95% CI 1-19-30%) and a high specificity of 99% (95% CI 98-100%). Sequencing results confirmed the presence of P.ovale curtisi. Conclusions This study provides baseline data for P.ovale spp surveillance in Kilifi County, primarily using PCR to improve diagnosis. These results suggest that malaria elimination and eradication efforts should not only concentrate on P. falciparum but should embrace a holistic approach towards elimination of all Plasmodium spp.

Trends in body mass index for people with and without HIV: Pooled analysis of nationally-representative health surveys from 10 countries and 173,800 adults in Africa.

It remains unclear if and how body mass index (BMI) levels have changed over time in HIV endemic regions. We described trends in mean BMI and prevalence of overweight between 2003-2019 in 10 countries in Africa including people living with (PLWH) and without (PLWoH) HIV. We pooled Demographic and Health Surveys (DHS) from countries where ≥2 surveys >4 years apart were available with height/weight measurements and HIV tests. HIV status was ascertained with a finger-prick dried blood spot (DBS) specimen tested in a laboratory. The DBS is taken as part of the regular DHS procedures. We summarized age and socioeconomic status standardized sex-specific mean BMI (kg/m2) and prevalence of overweight (BMI ≥25 kg/m2) by HIV status. We fitted country-level meta-regressions to ascertain if changes in ART coverage were correlated with changes in BMI. Before 2011, women LWH (22.9 [95% CI: 22.2-23.6]) and LWoH (22.6 [95% CI: 22.3-22.8]) had similar mean BMI. Over time, mean BMI increased more in women LWH (+0.8 [95% CI: 0.7-0.8] BMI units) than LWoH (+0.2 [95% CI: 0.2-0.3]). Before 2013, the mean BMI was similar between men LWH (21.1 (95% CI: 20.3-21.9)) and LWoH (20.8 (95% CI: 20.6-21.1)). Over time, mean BMI increased more in men LWoH (+0.3 [95% CI: 0.3-0.3]) than LWH (+0.1 [95% CI: 0.1-0.1]). The same profile was observed for prevalence of overweight. ART coverage was not strongly associated with BMI changes. Mean BMI and prevalence of overweight were similar in PLWH and PLWoH, yet in some cases the estimates for PWLH were on track to catch up with those for PLWoH. BMI monitoring programs are warranted in PLWH to address the rising BMI trends.

Preterm birth as a determinant of neurodevelopment and cognition in children (PRENCOG): protocol for an exposure-based cohort study in the UK

IntroductionPreterm birth (PTB) is strongly associated with encephalopathy of prematurity (EoP) and neurocognitive impairment. The biological axes linking PTB with atypical brain development are uncertain. We aim to elucidate the...

Performance of patient-collected dried blood spot specimens for HIV-1 viral load testing: evidence from the DO ART Study in South Africa.

Evaluate the clinical utility of patient-collected dried blood spots (DBS) in measuring HIV-1 viral load (VL) for monitoring antiretroviral therapy (ART) compared to provider-collected DBS and blood plasma. In a randomized trial of community-based delivery of ART in South Africa, we assessed performance of: (1) DBS specimens compared to plasma, and (2) participant-collected versus staff-collected DBS specimens, to measure HIV-1 VL. The bioMérieux NucliSENS EasyQ HIV-1 v2.0 assay was used for VL measurement. From October 2017 to November 2019, we collected 996 pairs of plasma/DBS specimens from 760 participants and 315 pairs of staff-/participant-collected DBS cards from 261 participants. We assessed DBS test sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) using the WHO failure threshold of 1000 copies/mL. Log-transformed VL was compared using concordance correlation coefficients (CCC) and mean differences from linear mixed models. In a population with 13% detectable VL, DBS VL compared with plasma VL had 91% (95% CI: 86-95) sensitivity, 99% (98-100) specificity, 94% (90-98) PPV, and 99% (98-99) NPV. We observed high agreement between staff-collected DBS VL and plasma VL (CCC: 0.94), and between participant-collected DBS VL and plasma VL (CCC: 0.92). Correlation between participant- and staff-collected DBS was very high (CCC: 0.97; mean difference for those with a detectable result: -0.10 log 10 copies/mL [-0.21-0.02]). VL results from participant-collected DBS are clinically comparable with those collected by clinical staff and using blood plasma. Self-collected DBS has potential for use for ART monitoring outside the clinic.

COMPARATIVE ANALYSIS OF TREC AND KREC ASSAYS FOR DIAGNOSIS OF PID IN DIFFERENT COUNTRIES

Nationwide neonatal screening programs of lymphocyte production using T-cell recombination excision circles (TREC) and kappa-deleting element recombination circle (KREC) have been important tools for the timely diagnosis of primary immunodeficiency (PID). Diagnosis and treatment of congenital defects of the immune system have made significant strides in many countries. However, a significant part of the children with severe immunodeficiency in the first year of life are diagnosed posthumously. Immunodeficiencies are under diagnosed primarily due to the lack of opportunities for early diagnosis and low awareness of these pathologies in doctors and the other healthcare professionals. Therefore, the issue and importance of early SCID detection using newborn screening assays become an essential public health problem. Newborn screening, particularly through TREC and KREC assays, has emerged as a promising avenue for identifying PID in its nascent stages. Early diagnosis not only facilitates prompt and targeted intervention, but also offers the opportunity to provide improved long-term outcomes for individuals facing these complex disorders. Screening for severe combined immunodeficiency (SCID) was introduced in the Swedish newborn screening program in August 2019, and according to the results from the first year, TREC, KREC and actin beta (ACTB) levels were measured by multiplex qPCR in dried blood spots (DBS) that obtained from 115,786 newborns and children under two years of age. On the basis of low TREC levels, 73 children were requested to undergo further clinical evaluation, resulting in the diagnosis of T-cell lymphopenia in 21 children. The DEPISTREC pilot study in France compared 190,517 infants screened for TREC with a control group of 1,400,000 children. TREC screening identified three patients with SCID, compared to 28 in the control group. Unfortunately, five children in the control group died of SCID before waiting for HSCT, which could potentially have been prevented by TREC screening. An economic analysis showed that the main cost factors were morbidity and cost per test and demonstrated that routine SCID screening was feasible and effective. In addition, two US states, Wisconsin and Massachusetts, have conducted pilot projects funded by the Center for Disease Control to evaluate the feasibility and effectiveness of newborn screening (NBS) for severe combined immunodeficiency (SCID) using the TREC assay. In Wisconsin, 71,000 infants were screened in 2008, identifying eight infants with T-lymphocytopenia, including one successfully treated with cord blood hematopoietic stem cell transplantation (HSCT). In Massachusetts, 100,597 infants were screened in 2009-2010 where twenty-nine infants with T-lymphocytopenia were identified, one of whom had SCID due to a compound heterozygous mutation in JAK3 and also received successful HSCT from an unrelated donor. After successfully identifying T lymphocytopenia in these experiments, the Advisory Committee on Hereditary Diseases of Newborns and Children of the Health and Human Services recommended that SCID be included in a uniform newborn screening panel. Therefore, newborn screening based on TREC and KREC assay programs is expected to provide early detection, prevent infections and prompt treatment, eventually improving overall survival. The ability to detect and intervene in the early stages of immunodeficiency diseases not only improves the prognosis for affected individuals but also enhances our understanding of the prevalence and spectrum of PID in the newborn population.

Generation Victoria (GenV): Creating a large consented longitudinal infrastructure for discovery and intervention research

Designed to help solve complex problems facing children and adults, Generation Victoria is Australia’s largest-ever birth cohort, and the only such cohort mounted internationally during the COVID-19 pandemic. Here, we describe progress in bringing together this ‘cell-to-society’ consented cohort with diverse existing data and biosamples assets. GenV is a whole-of-state consented cohort open to all Victorian children born October 2021-October 2023 and their parents. With over 117,000 participants to date (babies, mothers, fathers and non-binary parents), GenV closely reflects Australia's diverse demographics. At recruitment parents consent to GenV accessing (a) government managed and routinely collected administrative datasets across health, primary care, education, social care and geospatial and clinical datasets, (b) residual biosamples, (c) clinical and other service records and (d) spatial data. To date, GenV has developed protocols, governance and technical requirements for linking birthing hospitals clinical data, state based administrative datasets and residual samples from statewide pathology labs. In pilot studies we have achieved high linkages rate (over 98%) with the state-based linkage spine and with clinical records from one birthing hospital. Universal newborn blood spot linkage is nearing completion. We are developing methods to include our natural and built environment exposome platform, antenatal imaging and trials data. While challenging, GenV has encountered no significant barriers in creating an enduring, linked and secure data resource to advance future evidence-based decision making for child, family and adult outcomes. Our collaborative approach welcomes partnerships to co-build and enhance the muti-sectoral data and its utility.

EYoung men's experiences of violence and poverty and the relationship to sexually transmissible HIV: a cross sectional study from rural South Africa.

Young (ages 18-35 years) men are inadequately engaged in HIV prevention and treatment globally, including in South Africa, increasing the likelihood of them having sexually transmissible HIV (i.e. living with HIV but with high viral loads). We sought to understand how men's experiences of poverty and violence, impacted on transmissible HIV, directly or indirectly via mental health and substance misuse. Rural communities in northern KwaZulu-Natal, South Africa. Cross-sectional population-based random selection (September 2018-June 2019), assessing transmissible HIV (living with HIV and viral load ≥400 copies/mL) via dried blood spots, and socio-demographic data. Structural equation models (SEM), assessed direct and indirect pathways from food insecurity and violence experience to transmissible-HIV, with mediators common mental disorders, alcohol use, gender inequitable attitudes and perceptions of life chances. 2,086 young (ages 18-36 years) men and 8.6%(n=178) men had transmissible HIV. In SEM no direct pathways between food insecurity, or violence experience, and transmissible HIV. Poor mental health and alcohol use mediated the relationship between violence experience and food insecurity and transmissible HIV. Life chances also mediated the food insecurity to transmissible HIV pathway. There was a high level of transmissible HIV in a representative sample of young men. The analysis highlights the need to address both the proximate 'drivers' poor mental health and substance misuse, as well as the social contexts shaping these among young men, namely poverty and violence experience. Building holistic interventions that adequately engage these multiple challenges is critical for improving HIV among young men.

Consistency in the Assessment of Dried Blood Spot Specimen Size and Quality in U.K. Newborn Screening Laboratories.

In 2015, U.K. newborn screening (NBS) laboratory guidelines were introduced to standardize dried blood spot (DBS) specimen quality acceptance and specify a minimum acceptable DBS diameter of ≥7 mm. The UK 'acceptable' avoidable repeat rate (AVRR) is ≤2%. To assess inter-laboratory variability in specimen acceptance/rejection, two sets of colored scanned images (n = 40/set) of both good and poor-quality DBS specimens were distributed to all 16 U.K. NBS laboratories for evaluation as part of an external quality assurance (EQA) assessment. The mean (range) number of specimens rejected in the first EQA distribution was 7 (1-16) and in the second EQA distribution was 7 (0-16), demonstrating that adherence to the 2015 guidelines was highly variable. A new minimum standard for DBS size of ≥8 mm (to enable a minimum of six sub-punches from two DBS) was discussed. NBS laboratories undertook a prospective audit and demonstrated that using ≥8 mm as the minimum acceptable DBS diameter would increase the AVRR from 2.1% (range 0.55% to 5.5%) to 7.8% (range 0.55% to 22.7%). A significant inverse association between the number of specimens rejected in the DBS EQA distributions and the predicted AVVR (using ≥8 mm minimum standard) was observed (r = -0.734, p = 0.003). Before implementing more stringent standards, the impact of a standard operating procedure (SOP) designed to enable a standardized approach of visual assessment and using the existing ≥7 mm diameter (to enable a minimum of four sub-punches from two DBS) as the minimum standard was assessed in a retrospective audit. Implementation of the SOP and using the ≥7 mm DBS diameter would increase the AVRR from 2.3% (range 0.63% to 5.3%) to 6.5% (range 4.3% to 20.9%). The results demonstrate that there is inconsistency in applying the acceptance/rejection criteria, and that a low AVVR is not an indication of good-quality specimens being received into laboratories. Further work is underway to introduce and maintain standards without increasing the AVRR to unacceptable levels.

High-risk screening for late-onset Pompe disease in China: An expanded multicenter study.

Late-onset Pompe disease (LOPD) is caused by a genetic deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA), leading to progressive limb-girdle weakness and respiratory impairment. The insidious onset of non-specific early symptoms often prohibits timely diagnosis. This study aimed to validate the high-risk screening criteria for LOPD in the Chinese population. A total of 726 patients were included, including 96 patients under 14 years of age. Dried blood spots (DBS) and tandem mass spectrometry (MS/MS) were employed to evaluate serum GAA activity. Forty-four patients exhibited a decreased GAA activity, 16 (2.2%) of which were confirmed as LOPD by genetic testing. Three previously unreported GAA mutations were also identified. The median diagnostic delay was shortened to 3 years, which excelled the previous retrospective studies. At diagnosis, most patients exhibited impaired respiratory function and/or limb-girdle weakness. Elevated serum creatine kinase (CK) levels were more frequently observed in patients who manifested before age 16. Overall, high-risk screening is a feasible and efficient method to identify LOPD patients at an early stage. Patients over 1 year of age with either weakness in axial and/or proximal limb muscles, or unexplained respiratory distress shall be subject to GAA enzymatic test, while CK levels above 2 times the upper normal limit shall be an additional criterion for patients under 16. This modified high-risk screening criteria for LOPD requires further validation in larger Chinese cohorts.

Integrated Serosurveillance for Onchocerciasis, Lymphatic Filariasis, and Schistosomiasis in North Darfur, Sudan.

Sudan is endemic for multiple neglected tropical diseases, including trachoma, onchocerciasis (OV), lymphatic filariasis (LF), and schistosomiasis (SCH). In 2019, dried blood spot samples were collected for a baseline trachoma serosurvey in three localities (El Seraif, Kotom, and Saraf Omrah) in North Darfur State. None were classified previously as OV- or LF-endemic, although low levels of SCH had been identified in all three. Approximately 30 households from 25 communities in each locality were selected by multistage cluster random sampling. Collections of DBSs were analyzed by multiplex bead assay for antibodies to multiple pathogens. This paper presents data on OV (Ov16), LF (Wb123, Bm14, Bm33), and SCH (soluble egg antigen [SEA], Sm25) antibodies among 8,322 individuals from 2,119 households. The survey-adjusted seroprevalence estimates for Ov16 were <0.3% in all localities. Lymphatic filariasis-antigen seroprevalences were discordant. Seroprevalence estimates ranged from 4.6-6.0% (Wb123), 0.99-1.4% (Bm14), and 29.2-33.3% (Bm33). Schistosomiasis seroprevalence estimates among school-aged children ranged from 2.7-8.0% (SEA) and 10.9-15.6% (Sm25). Ov16 seropositivity was low and supported the localities' classification as nonendemic. The results suggested LF exposure, but discordance between antigens, challenges defining seropositivity thresholds, and the absence of programmatic guidance based on antibody serology alone for Wuchereria bancrofti indicate a need for remapping surveys to confirm transmission. Schistosomiasis antibody levels were high enough to warrant further mapping to guide treatment decisions. The lack of gold standards limited interpretation of results, particularly for LF, but in resource-challenged areas, integrated serological surveillance offers the possibility of efficient monitoring of exposure to multiple diseases.

Screening for Fabry disease in patients with left ventricular hypertrophy in China: A multicentre and prospective study.

Left ventricular hypertrophy (LVH) is frequently detected via echocardiography in individuals with Fabry disease (FD), sometimes leading to confusion with hypertrophic cardiomyopathy (HCM) of other aetiologies. Considering this diagnosis challenge, FD should be included in the list of differential diagnosis for patients presenting with LVH. To address this concern, we conducted a prospective screening study in China, using dried blood spot (DBS) testing, to evaluate patients with unexplained LVH. Our study was designed as a nationwide, multicentre prospective investigation. A total of 1015 patients from 55 different centres who were diagnosed with LVH by echocardiography were screened in the study from September 2022 to December 2023. Demographic information, biochemistry data, echocardiography parameters and clinical observations were meticulously collected from all participants. The DBS method was used to assess α-galactosidase A (α-Gal A) activity in males and both α-Gal A and globotriaosylsphingosine (lyso-Gb3) levels in females. The final screening population included 906 patients (589 males, 65%) with LVH, characterized by a mean maximal myocardial thickness of 14.8±4.6mm and an average age of 56.9±17.2years. In total, 43 patients (38 males, 5 females) exhibited low α-Gal A activity measurement (<2.2μmol/L), while 21 patients (10 males, 11 females) presented low α-Gal A activity or elevated lyso-Gb3 levels (>1.1ng/mL). Among these patients, eight individuals (7 males and 1 female) were genetically confirmed to harbour pathogenic GLA mutations, resulting in a total prevalence of 0.88%. Compared with patients without FD, patients with FD tended to have proteinuria (75% vs. 21.2%, P=0.001), family history of HCM (37.5% vs. 2.3%, P<0.01) and neuropathic pain (37.5% vs. 4.4%, P<0.01) but lower systolic blood pressure (118.5±12.5 vs. 143.3±29.3mmHg, P=0.017). Five mutations were previously recognized as associated with FD while the remaining two, p.Asp313Val (c.938A>T) and c.547+3A>G, were deemed potentially pathogenic. Subsequent familial validation post-diagnosis identified an additional 14 confirmed cases. This pioneering screening study for FD among Chinese patients with unexplained LVH using DBS measurement, revealed an FD detection rate of 0.88%. Our findings confirmed that the combined measurement of lyso-Gb3 and α-Gal A activity is beneficial for primary screening of FD in patients with LVH. Given the availability of efficacious therapies and the value of cascade screening in extended families, early detection of FD in LVH patients is clinically important.

Public Knowledge and Awareness About Hemorrhoids and the Reasons for Late Presentation to Local Doctors in Makkah Region, Saudi Arabia: A Cross-Sectional Exploratory Study.

Background Hemorrhoids, also known as piles, manifest as anal lumps with or without bleeding. This study aims to explore and assess the public knowledge and awareness about hemorrhoids and the factors leading to late presentation to local doctors in the Makkah region of Saudi Arabia. Methodology A questionnaire-based, cross-sectional study was conducted targeting the Saudi population aged 18 years and more living in the Makkah region. The study was conducted from May 1 to May 29, 2023. Data collection was done using electronic Google Forms for data collection. The questionnaire was divided into three main sections covering demographics, knowledge items, and personal and family history of hemorrhoids. Results A total of 495 participants completed the study questionnaire. Participants' ages ranged from 18 to 65 years with a mean age of 25.1 ± 13.7 years old. Overall, 414 (83.6%) were males. Only 106 (21.4%) had an overall good knowledge level. The majority of the participants (78.6%, 389) had poor knowledge. Pain (78% of the participants) was the most common reason for seeking medical advice, followed by feeling uncomfortable (43.3%), and the presence of blood or blood spots in the stool (41.1%). Among others who never sought medical advice, the most reported reason was being embarrassed (66.7%). Conclusions This study revealed that the prevalence of early seeking medical advicewas low as many did not because of stigma. The main reasons for seeking medical care were disease-related symptoms, and embarrassment was the main reported barrier.

Interlaboratory Harmonization Study and Prospective Evaluation of the PURE–Trypanosoma cruzi–Loop-Mediated Isothermal Amplification Assay for Detecting Parasite DNA in Newborn's Dried Blood Spots

Timely diagnosis of vertical Trypanosoma cruzi infections involves microscopy-based detection of circulating parasites from peripheral blood, which lacks sensitivity and is operator dependent. Consequently, most children born to T. cruzi-infected mothers are required to undergo serological testing after nine months, which risks loss to follow-up. Alternatively, the Loop-mediated isothermal amplification (LAMP) test for T. cruzi DNA offers high analytical and clinical performance and easy to use in low-complexity laboratories. Recently, we optimized this technique using an ultra-rapid DNA extraction method combined with the LAMP in dried blood spots (DBS) on FTA cards. The procedure has been implemented in ten public maternities across Paraguay, Bolivia, and Argentina, involving the training of 14 technicians. Operators' performance was evaluated using a standardized DBS testing panel for harmonization, including negative controls and DBS samples artificially contaminated with T. cruzi at 50 and 20 cells/mL. There was strong agreement (ĸ = 0.924) for controls and 50 cells/mL samples, and good agreement (ĸ = 0.718) across all testing panels, even at the detection limit of the test. A prospective study collected 306 DBS from 222 newborns at birth and/or two months, detecting T. cruzi microscopically in four cases. LAMP identified eight positive cases and perfectly aligned with Real Time PCR (ĸ = 1), demonstrating higher sensitivity than microscopic observation for early detection of infection in infants.

A risk-differentiated, community-led intervention to strengthen uptake and engagement with HIV prevention and care cascades among female sex workers in Zimbabwe (AMETHIST): a cluster randomised trial

Female sex workers remain disproportionately affected by HIV. The aim of this study was to determine the effect of risk-differentiated, peer-led support for female sex workers in Zimbabwe on the risk of HIV acquisition and HIV transmission from sex among female sex workers. In this cluster randomised, open-label, controlled study, 22 clinics dedicated to female sex workers co-located in government health facilities throughout Zimbabwe were allocated (1:1, through restricted randomisation) to usual care or AMETHIST intervention. Usual care comprised HIV testing, pre-exposure prophylaxis (PrEP), referral to government antiretroviral therapy (ART) services, contraception, condoms, syndromic management of sexually transmitted infections, health education, legal advice, and peer support. AMETHIST added peer-led microplanning tailored to individuals' risk and participatory self-help groups. All cisgender women (aged >18 years) who had sold sex within the past 30 days and lived or worked within trial cluster areas were eligible. Intervention status was not masked to programme implementers but was masked to survey teams and laboratory staff. After 28 months, a respondent-driven sampling (RDS) survey was done in the female sex worker population around each clinic, which measured the primary outcome, the combined proportion of female sex workers in the surveyed population at risk of transmitting HIV (ie, were HIV positive, not virally suppressed, and not consistently using condoms) or at risk of acquiring HIV (ie, were HIV negative and not consistently using condoms or PrEP). We report prespecified analyses of the disaggregated proportions of female sex workers in the surveyed population at risk of either transmission or acquisition of HIV. Analyses were prespecified, RDS-weighted, and age-adjusted. This trial is registered with the Pan African Clinical Trials Registry, PACTR202007818077777. The AMETHIST intervention was started on May 15, 2019, and data were collected from June 1, 2019, until Dec 13, 2021. The RDS survey was done from Oct 18 to Dec 13, 2021, with 2137 women included in the usual care group (11 clusters) and 2131 in the AMETHIST intervention group (11 clusters) after excluding survey seeds (n=132) and women with missing key data (n=44). 1973 (46·2%) of the 4268 female sex workers surveyed were living with HIV; of these, 863 (93·5%; RDS-adjusted) of 931 women in the intervention group and 927 (88·8%) of 1042 in the usual care group were virologically suppressed. 287 (22·4%) of 1200 HIV-negative women in the intervention group and 194 (15·7%) of 1096 in the usual care group reported currently taking PrEP, of whom only two (0·4%) of 569 had protective tenofovir diphosphate concentrations in dried blood spots (>700 fmol/dried blood punch). There was no effect of the intervention on the primary endpoint of risk of both HIV transmission and acquisition (intervention group n=1156/2131, RDS-adjusted proportion 55·3%; usual care group n=1104/2137, RDS-adjusted proportion 52·7%; age-adjusted risk difference -0·9%, 95% CI -5·7% to 3·9%, p=0·70). For the secondary outcomes, the proportion of women living with HIV at risk of transmission was low and significantly reduced in the intervention group (n=63/931, RDS-adjusted proportion 5·8%) compared with the usual care group (103/1041, 10·4%), with an age-adjusted risk difference of -5·5% (95% CI -8·2% to -2·9%, p=0·0003). Risk of acquisition among HIV-negative women was similar in the intervention (n=1093/1200, RDS-adjusted proportion 92·1%) and the usual care group (1001/1096, 92·2%), with an age-adjusted risk difference of -0·6% (95% CI -4·6 to 3·4, p=0·74). There was no overall benefit of the intervention on combined risk of transmission or acquisition. Viral load suppression in women living with HIV was high and appeared to be further improved by AMETHIST, suggesting potential for impressive uptake and adherence to ART in vulnerable and mobile populations. Sustaining treatment and reinvigorating prevention remain crucial. The Wellcome Trust and the Bill & Melinda Gates Foundation. For the Shona and Ndebele translations of the abstract see Supplementary Materials section.

P23-02 Detection of 25 PFAS in human blood by quantitative dried blood spots microsampling for large population monitoring

P23-02 Detection of 25 PFAS in human blood by quantitative dried blood spots microsampling for large population monitoring

Utilising integrated bio-behavioural surveillance (IBBS) to investigate declining hepatitis C antibody prevalence among people who inject drugs in the Australian Needle and Syringe Program Survey

BackgroundPrevalence of hepatitis C virus (HCV) antibody (Ab) on dried blood spot (DBS) samples in the Australian Needle and Syringe Program Survey (ANSPS) decreased nationally from 57 % in 2015 to 32 % in 2022. We aimed to investigate potential explanations for this decline. MethodsChanges in DBS HCV Ab prevalence were investigated by redefining positive cases as those with those with either a positive HCV Ab test result or a self-reported history of ever having HCV treatment (modified prevalence), examining HCV Ab prevalence by birth and age cohorts, and assessing trends in key risk behaviours. ResultsOverall prevalence of DBS HCV Ab declined rapidly and significantly from 57 % in 2015 to 32 % in 2022 (p < 0.001) however modified HCV Ab prevalence remained stable over time (85 % and 88 % in 2015 and 2022, respectively, p = 0.357). The proportion of participants with negative HCV Ab and self-reported HCV infection increased from 20 % in 1995 to 40 % in 2022 (p < 0.001) and the proportion with negative HCV Ab and lifetime HCV treatment increased from 3 % in 1999 to 67 % in 2022 (p < 0.001). We also observed a decreasing trend in DBS HCV Ab prevalence in all birth and age cohorts with a noticeable acceleration in the decline commensurate with the advent of HCV DAA treatment. A long-term decreasing trend was also observed for key risk behaviours (p < 0.001) however the short-term trend was not significant for recent receptive syringe sharing. ConclusionThe temporal decline in HCV Ab prevalence appears related to reduced sensitivity of DBS HCV Ab detection with viral clearance following treatment. Since 2016, HCV treatment uptake has increased markedly including among people who inject drugs. In this context, continuing to monitor HCV Ab prevalence by DBS testing is problematic, with a shift to surveillance of active infection the most relevant to guide policy and practice in this setting.

Evaluation of hydroxychloroquine or chloroquine for the prevention of COVID-19 (COPCOV): A double-blind, randomised, placebo-controlled trial.

Hydroxychloroquine (HCQ) has proved ineffective in treating patients hospitalised with Coronavirus Disease 2019 (COVID-19), but uncertainty remains over its safety and efficacy in chemoprevention. Previous chemoprevention randomised controlled trials (RCTs) did not individually show benefit of HCQ against COVID-19 and, although meta-analysis did suggest clinical benefit, guidelines recommend against its use. Healthy adult participants from the healthcare setting, and later from the community, were enrolled in 26 centres in 11 countries to a double-blind, placebo-controlled, randomised trial of COVID-19 chemoprevention. HCQ was evaluated in Europe and Africa, and chloroquine (CQ) was evaluated in Asia, (both base equivalent of 155 mg once daily). The primary endpoint was symptomatic COVID-19, confirmed by PCR or seroconversion during the 3-month follow-up period. The secondary and tertiary endpoints were: asymptomatic laboratory-confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection; severity of COVID-19 symptoms; all-cause PCR-confirmed symptomatic acute respiratory illness (including SARS-CoV-2 infection); participant reported number of workdays lost; genetic and baseline biochemical markers associated with symptomatic COVID-19, respiratory illness and disease severity (not reported here); and health economic analyses of HCQ and CQ prophylaxis on costs and quality of life measures (not reported here). The primary and safety analyses were conducted in the intention-to-treat (ITT) population. Recruitment of 40,000 (20,000 HCQ arm, 20,000 CQ arm) participants was planned but was not possible because of protracted delays resulting from controversies over efficacy and adverse events with HCQ use, vaccine rollout in some countries, and other factors. Between 29 April 2020 and 10 March 2022, 4,652 participants (46% females) were enrolled (HCQ/CQ n = 2,320; placebo n = 2,332). The median (IQR) age was 29 (23 to 39) years. SARS-CoV-2 infections (symptomatic and asymptomatic) occurred in 1,071 (23%) participants. For the primary endpoint the incidence of symptomatic COVID-19 was 240/2,320 in the HCQ/CQ versus 284/2,332 in the placebo arms (risk ratio (RR) 0.85 [95% confidence interval, 0.72 to 1.00; p = 0.05]). For the secondary and tertiary outcomes asymptomatic SARS-CoV-2 infections occurred in 11.5% of HCQ/CQ recipients and 12.0% of placebo recipients: RR: 0.96 (95% CI, 0.82 to 1.12; p = 0.6). There were no differences in the severity of symptoms between the groups and no severe illnesses. HCQ/CQ chemoprevention was associated with fewer PCR-confirmed all-cause respiratory infections (predominantly SARS-CoV-2): RR 0.61 (95% CI, 0.42 to 0.88; p = 0.009) and fewer days lost to work because of illness: 104 days per 1,000 participants over 90 days (95% CI, 12 to 199 days; p < 0.001). The prespecified meta-analysis of all published pre-exposure RCTs indicates that HCQ/CQ prophylaxis provided a moderate protective benefit against symptomatic COVID-19: RR 0.80 (95% CI, 0.71 to 0.91). Both drugs were well tolerated with no drug-related serious adverse events (SAEs). Study limitations include the smaller than planned study size, the relatively low number of PCR-confirmed infections, and the lower comparative accuracy of serology endpoints (in particular, the adapted dried blood spot method) compared to the PCR endpoint. The COPCOV trial was registered with ClinicalTrials.gov; number NCT04303507. In this large placebo-controlled, double-blind randomised trial, HCQ and CQ were safe and well tolerated in COVID-19 chemoprevention, and there was evidence of moderate protective benefit in a meta-analysis including this trial and similar RCTs. ClinicalTrials.gov NCT04303507; ISRCTN Registry ISRCTN10207947.