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38,995 result(s) for "Population Surveillance"
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A pooled testing strategy for identifying SARS-CoV-2 at low prevalence
Suppressing infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will probably require the rapid identification and isolation of individuals infected with the virus on an ongoing basis. Reverse-transcription polymerase chain reaction (RT–PCR) tests are accurate but costly, which makes the regular testing of every individual expensive. These costs are a challenge for all countries around the world, but particularly for low-to-middle-income countries. Cost reductions can be achieved by pooling (or combining) subsamples and testing them in groups 1 – 7 . A balance must be struck between increasing the group size and retaining test sensitivity, as sample dilution increases the likelihood of false-negative test results for individuals with a low viral load in the sampled region at the time of the test 8 . Similarly, minimizing the number of tests to reduce costs must be balanced against minimizing the time that testing takes, to reduce the spread of the infection. Here we propose an algorithm for pooling subsamples based on the geometry of a hypercube that, at low prevalence, accurately identifies individuals infected with SARS-CoV-2 in a small number of tests and few rounds of testing. We discuss the optimal group size and explain why, given the highly infectious nature of the disease, largely parallel searches are preferred. We report proof-of-concept experiments in which a positive subsample was detected even when diluted 100-fold with negative subsamples (compared with 30–48-fold dilutions described in previous studies 9 – 11 ). We quantify the loss of sensitivity due to dilution and discuss how it may be mitigated by the frequent re-testing of groups, for example. With the use of these methods, the cost of mass testing could be reduced by a large factor. At low prevalence, the costs decrease in rough proportion to the prevalence. Field trials of our approach are under way in Rwanda and South Africa. The use of group testing on a massive scale to monitor infection rates closely and continually in a population, along with the rapid and effective isolation of people with SARS-CoV-2 infections, provides a promising pathway towards the long-term control of coronavirus disease 2019 (COVID-19). A mathematical algorithm for population-wide screening of SARS-CoV-2 infections using pooled parallel RT–PCR tests requires considerably fewer tests than individual testing procedures and has minimal delays in the identification of individuals infected with SARS-CoV-2.
Faecal immunochemical tests (FIT) versus colonoscopy for surveillance after screening and polypectomy: a diagnostic accuracy and cost-effectiveness study
ObjectiveThe English Bowel Cancer Screening Programme (BCSP) recommends 3 yearly colonoscopy surveillance for patients at intermediate risk of colorectal cancer (CRC) postpolypectomy (those with three to four small adenomas or one ≥10 mm). We investigated whether faecal immunochemical tests (FITs) could reduce surveillance burden on patients and endoscopy services.DesignIntermediate-risk patients (60–72 years) recommended 3 yearly surveillance were recruited within the BCSP (January 2012–December 2013). FITs were offered at 1, 2 and 3 years postpolypectomy. Invitees consenting and returning a year 1 FIT were included. Participants testing positive (haemoglobin ≥40 µg/g) at years one or two were offered colonoscopy early; all others were offered colonoscopy at 3 years. Diagnostic accuracy for CRC and advanced adenomas (AAs) was estimated considering multiple tests and thresholds. We calculated incremental costs per additional AA and CRC detected by colonoscopy versus FIT surveillance.Results74% (5938/8009) of invitees were included in our study having participated at year 1. Of these, 97% returned FITs at years 2 and 3. Three-year cumulative positivity was 13% at the 40 µg/g haemoglobin threshold and 29% at 10 µg/g. 29 participants were diagnosed with CRC and 446 with AAs. Three-year programme sensitivities for CRC and AAs were, respectively, 59% and 33% at 40 µg/g, and 72% and 57% at 10 µg/g. Incremental costs per additional AA and CRC detected by colonoscopy versus FIT (40 µg/g) surveillance were £7354 and £180 778, respectively.ConclusionsReplacing 3 yearly colonoscopy surveillance in intermediate-risk patients with annual FIT could reduce colonoscopies by 71%, significantly cut costs but could miss 30%–40% of CRCs and 40%–70% of AAs.Trial registration number ISRCTN18040196; Results.
How short or long should be a questionnaire for any research? Researchers dilemma in deciding the appropriate questionnaire length
A questionnaire plays a pivotal role in various surveys. Within the realm of biomedical research, questionnaires serve a role in epidemiological surveys and mental health surveys and to obtain information about knowledge, attitude, and practice (KAP) on various topics of interest. Questionnaire in border perspective can be of different types like self-administered or professionally administered and according to the mode of delivery paper-based or electronic media-based. Various studies have been conducted to assess the appropriateness of a questionnaire in a particular field and methods to translate and validate them. But very little is known regarding the appropriate length and number of questions in a questionnaire and what role it has in data quality, reliability, and response rates. Hence, this narrative review is to explore the critical issue of appropriate length and number of questions in a questionnaire while questionnaire designing.
Clinical Trials of Active Surveillance of Papillary Microcarcinoma of the Thyroid
Background The incidence of thyroid cancer is increasing globally. This is mainly due to the increase in the detection of small papillary carcinomas, including papillary microcarcinomas (PMC) 1 cm or smaller. It was suggested recently that PMCs are overdiagnosed and overtreated. Methods In 1993, the author proposed a clinical trial to compare surgery and observation for low-risk PMC at doctors’ meeting in Kuma Hospital, which was approved and the trial started in the same year. Patients choose immediate surgery or observation. This paper shares our 22-year experience with the active surveillance of more than 2000 patients with low-risk PMC and compares the outcomes of immediate surgery with that of active observation. Results The oncological outcomes of these management groups were similarly excellent. In our active surveillance trial on 1235 patients, 8 % of patients showed tumor enlargement by 3 mm or more at 10 years of observation, and 3.8 % of the patients showed novel appearance of lymph node metastasis at 10 years. Patients 40 years or younger tended to show progression of the disease. Patients with these slight progressions of the disease were successfully treated with a rescue surgery. None of the patients in both study groups died of the disease. However, incidences of unfavorable events, such as temporary vocal cord paralysis (VCP) and temporary and permanent hypoparathyroidism, were significantly higher in the immediate surgery group than in the observation group (4.1 vs. 0.6 %, p  < 0.0001; 16.7 vs. 2.8 %, p  < 0.0001; and 1.6 vs. 0.08 %, p  < 0.0001, respectively). Permanent VCP occurred in two of the surgery group. Conclusions As a result, although we still offer two options, immediate surgery or observation, to patients with low-risk PMC at Kuma Hospital, we now strongly recommend observation as the best choice.
From Fax to Secure File Transfer Protocol: The 25-Year Evolution of Real-Time Syndromic Surveillance in England
The purpose of syndromic surveillance is to provide early warning of public health incidents, real-time situational awareness during incidents and emergencies, and reassurance of the lack of impact on the population, particularly during mass gatherings. The United Kingdom Health Security Agency (UKHSA) currently coordinates a real-time syndromic surveillance service that encompasses 6 national syndromic surveillance systems reporting on daily health care usage across England. Each working day, UKHSA analyzes syndromic data from over 200,000 daily patient encounters with the National Health Service, monitoring over 140 unique syndromic indicators, risk assessing over 50 daily statistical exceedances, and taking and recommending public health action on these daily. This English syndromic surveillance service had its origins as a small exploratory pilot in a single region of England in 1999 involving a new pilot telehealth service, initially reporting only on “cold or flu” calls. This pilot showed the value of syndromic surveillance in England, providing advanced warning of the start of seasonal influenza activity over existing laboratory-based surveillance systems. Since this initial pilot, a program of real-time syndromic surveillance has evolved from the single-system, -region, -indicator pilot (using manual data transfer methods) to an all-hazard, multisystem, automated national service. The suite of systems now monitors a wide range of syndromes, from acute respiratory illness to diarrhea to cardiac conditions, and is widely used in routine public health surveillance and for monitoring seasonal respiratory disease and incidents such as the COVID-19 pandemic. Here, we describe the 25-year evolution of the English syndromic surveillance system, focusing on the expansion and improvements in data sources and data management, the technological and digital enablers, and novel methods of data analytics and visualization.
The epidemiological signature of influenza B virus and its B/Victoria and B/Yamagata lineages in the 21st century
We describe the epidemiological characteristics, pattern of circulation, and geographical distribution of influenza B viruses and its lineages using data from the Global Influenza B Study. We included over 1.8 million influenza cases occurred in thirty-one countries during 2000-2018. We calculated the proportion of cases caused by influenza B and its lineages; determined the timing of influenza A and B epidemics; compared the age distribution of B/Victoria and B/Yamagata cases; and evaluated the frequency of lineage-level mismatch for the trivalent vaccine. The median proportion of influenza cases caused by influenza B virus was 23.4%, with a tendency (borderline statistical significance, p = 0.060) to be higher in tropical vs. temperate countries. Influenza B was the dominant virus type in about one every seven seasons. In temperate countries, influenza B epidemics occurred on average three weeks later than influenza A epidemics; no consistent pattern emerged in the tropics. The two B lineages caused a comparable proportion of influenza B cases globally, however the B/Yamagata was more frequent in temperate countries, and the B/Victoria in the tropics (p = 0.048). B/Yamagata patients were significantly older than B/Victoria patients in almost all countries. A lineage-level vaccine mismatch was observed in over 40% of seasons in temperate countries and in 30% of seasons in the tropics. The type B virus caused a substantial proportion of influenza infections globally in the 21st century, and its two virus lineages differed in terms of age and geographical distribution of patients. These findings will help inform health policy decisions aiming to reduce disease burden associated with seasonal influenza.
Narrow Band Imaging for Detection of Dysplasia in Colitis: A Randomized Controlled Trial
In ulcerative colitis surveillance, chromoendoscopy improves dysplasia detection 3 – 5-fold compared with white light endoscopy (WLE). The aim of this study was to investigate whether narrow band imaging (NBI) can improve dysplasia detection compared with WLE. This was a randomized, parallel-group trial. A total of 220 patients were needed to be recruited to detect a threefold increase in dysplasia detection. In all, 112 patients with long-standing ulcerative colitis were randomized to colonoscopic extubation with NBI (56) or WLE (56) (1:1 ratio) at two tertiary endoscopy units in the United Kingdom. Targeted biopsies of suspicious areas and quadrantic random biopsies every 10 cm were taken in both groups. The primary outcome measure was the proportion of patients with at least one area of dysplasia detected. In a prespecified mid-point analysis, the criteria for trial discontinuation were met and the trial was stopped and analyzed at this point. There was no difference in the primary outcome between the two groups, with 5 patients having at least one dysplastic lesion in each group (odds ratio (OR) 1.00, 95 % confidence interval (95 % CI) 0.27 – 3.67, P = 1.00). This remained unchanged when adjusted for other variables (OR 0.69, 95 % CI 0.16 – 2.96, P = 0.62). Overall, dysplasia detection was 9 % in each arm. Yield of dysplasia from random nontargeted biopsies was 1 / 2,707 (0.04 % ). Overall, in this multicenter parallel-group trial, there was no difference in dysplasia detection when using NBI compared with high-definition WLE colonoscopy. Random background biopsies were ineffective in detecting dysplasia.
A randomized controlled trial of digital breast tomosynthesis versus digital mammography in population-based screening in Bergen: interim analysis of performance indicators from the To-Be trial
ObjectivesTo describe a randomized controlled trial (RCT) of digital breast tomosynthesis including synthesized two-dimensional mammograms (DBT) versus digital mammography (DM) in a population-based screening program for breast cancer and to compare selected secondary screening outcomes for the two techniques.MethodsThis RCT, performed in Bergen as part of BreastScreen Norway, was approved by the Regional Committees for Medical Health Research Ethics. All screening attendees in Bergen were invited to participate, of which 89% (14,274/15,976) concented during the first year, and were randomized to DBT (n = 7155) or DM (n = 7119). Secondary screening outcomes were stratified by mammographic density and compared using two-sample t-tests, chi-square tests, ANOVA, negative binomial regression and tests of proportions (z tests).ResultsMean reading time was 1 min 11 s for DBT and 41 s for DM (p < 0.01). Mean time spent at consensus was 3 min 12 s for DBT and 2 min 12 s for DM (p < 0.01), while the rate of cases discussed at consensus was 6.4% and 7.4%, respectively for DBT and DM (p = 0.03). The recall rate was 3.0% for DBT and 3.6% for DM (p = 0.03). For women with non-dense breasts, recall rate was 2.2% for DBT versus 3.4% for DM (p = 0.04). The rate did not differ for women with dense breasts (3.6% for both). Mean glandular dose per examination was 2.96 mGy for DBT and 2.95 mGy for DM (p = 0.433).ConclusionsInterim analysis of a screening RCT showed that DBT took longer to read than DM, but had significantly lower recall rate than DM. We found no differences in radiation dose between the two techniques.Key Points• In this RCT, DBT was associated with longer interpretation time than DM• Recall rates were lower for DBT than for DM• Mean glandular radiation dose did not differ between DBT and DM
Crowdsourced surveillance for neglected tropical diseases, Nigeria
To validate a crowdsourced, image-based morbidity hotspot method for surveillance of neglected tropical diseases. We conducted our crowdsourced surveillance pilot implementation study between November 2022 and October 2024 in 45 communities across three Nigerian states, covering a population of 477 138 people. Three additional states, where the project was not implemented but surveillance data obtained, served as control. Residents self-reported suspected symptoms by using smartphones to capture and transmit images of skin and eye manifestations via digital communication platforms. An expert panel then examined the images to confirm signs of neglected tropical diseases. We used frequency and percentages to present data; we also compared incidence data from both pilot and control locations. In total, 512 subjects submitted images, either themselves or via a community focal point. Their mean age was 53  years (standard deviation: 20.7). Forty-six percent (234/512) were women and 55% (281/512) were farmers. Notably, 43% (218/512) had experienced symptoms of neglected tropical diseases for 1-5 years before our study and 85% (437/512) had not received any intervention. Of all photos submitted, 75% (386/512) showed signs of neglected tropical diseases. In Ondo state crowdsourced surveillance led to an average of 54.3 monthly reports, versus traditional surveillance which averaged 6.8 (  < 0.01). Cost analysis showed that crowdsourced surveillance cost 72.4 United States dollars per case detected. Our surveillance method outperformed traditional surveillance, showing its promise for enhancing neglected tropical disease surveillance. The method's ability to detect emerging conditions and support post-elimination surveillance reinforces its value.
Evaluating the impact of the DREAMS partnership to reduce HIV incidence among adolescent girls and young women in four settings: a study protocol
Background HIV risk remains unacceptably high among adolescent girls and young women (AGYW) in southern and eastern Africa, reflecting structural and social inequities that drive new infections. In 2015, PEPFAR (the United States President’s Emergency Plan for AIDS Relief) with private-sector partners launched the DREAMS Partnership, an ambitious package of interventions in 10 sub-Saharan African countries. DREAMS aims to reduce HIV incidence by 40% among AGYW over two years by addressing multiple causes of AGYW vulnerability. This protocol outlines an impact evaluation of DREAMS in four settings. Methods To achieve an impact evaluation that is credible and timely, we describe a mix of methods that build on longitudinal data available in existing surveillance sites prior to DREAMS roll-out. In three long-running surveillance sites (in rural and urban Kenya and rural South Africa), the evaluation will measure: (1) population-level changes over time in HIV incidence and socio-economic, behavioural and health outcomes among AGYW and young men (before, during, after DREAMS); and (2) causal pathways linking uptake of DREAMS interventions to ‘mediators’ of change such as empowerment, through to behavioural and health outcomes, using nested cohort studies with samples of ~ 1000–1500 AGYW selected randomly from the general population and followed for two years. In Zimbabwe, where DREAMS includes an offer of pre-exposure HIV prophylaxis (PrEP), cohorts of young women who sell sex will be followed for two years to measure the impact of ‘DREAMS+PrEP’ on HIV incidence among young women at highest risk of HIV. In all four settings, process evaluation and qualitative studies will monitor the delivery and context of DREAMS implementation. The primary evaluation outcome is HIV incidence, and secondary outcomes include indicators of sexual behavior change, and social and biological protection. Discussion DREAMS is, to date, the most ambitious effort to scale-up combinations or ‘packages’ of multi-sectoral interventions for HIV prevention. Evidence of its effectiveness in reducing HIV incidence among AGYW, and demonstrating which aspects of the lives of AGYW were changed, will offer valuable lessons for replication.