22 research outputs found
Findings from a cluster randomised trial of unconditional cash transfers in Niger.
Unconditional cash transfers (UCTs) are used as a humanitarian intervention to prevent acute malnutrition, despite a lack of evidence about their effectiveness. In Niger, UCT and supplementary feeding are given during the June-September "lean season," although admissions of malnourished children to feeding programmes may rise from March/April. We hypothesised that earlier initiation of the UCT would reduce the prevalence of global acute malnutrition (GAM) in children 6-59 months old in beneficiary households and at population level. We conducted a 2-armed cluster-randomised controlled trial in which the poorest households received either the standard UCT (4 transfers between June and September) or a modified UCT (6 transfers from April); both providing 130,000 FCFA/£144 in total. Eligible individuals (pregnant and lactating women and children 6- 0.05), despite improved food security (p < 0.05), possibly driven by increased fever/malaria in children (p < 0.001). Nonfood related drivers of malnutrition, such as disease, may limit the effectiveness of UCTs plus supplementary feeding to prevent malnutrition in this context. Caution is required in applying the findings of this study to periods of severe food insecurity
Assessing the use of an essential health package in a sector wide approach in Malawi
<p>Abstract</p> <p>Background</p> <p>The sector wide approach (SWAp) used in many developing countries is difficult to assess. One way is to consider the essential health package (EHP) which is commonly the vehicle for a SWAp's policies and plans. It is not possible to measure the impact of an EHP by measuring health outcomes in countries such as Malawi. But it is possible to assess the choice of interventions and their delivery in terms of coverage. This paper describes an attempt to assess the Malawi SWAp through its EHP using these available measures of technical efficiency.</p> <p>Methods</p> <p>A burden of disease model was used to identify the priority diseases and their estimated incidence. Data from the health management information system (HMIS) were used to measure the coverage of these interventions. A review of the cost-effectiveness of the chosen and potential interventions was undertaken to assess the appropriateness of each intervention used in the EHP. Expenditure data were used to assess the level of funding of the EHP.</p> <p>Results</p> <p>33 of the 55 EHP interventions were found to be potentially cost-effective (<150/DALY) and cost-effective estimates were not available for ten. 15 potential interventions, which were cost-effective and tackling one of the top 20 ranked diseases, were identified.</p> <p>Provision had increased in nearly all EHP services over the period of the SWAp. The rates of out patient attendances and inpatient days per 1000 population had both increased from 929 attendances in 2002/3 to 1135 in 2007/08 and from 124 inpatient days in 2002/03 to 179 in 2007/08.</p> <p>However, by 2007/08 the mean gap between what was required and what was provided was 0.68 of the estimated need. Two services involving the treatment of malaria were overprovided, but the majority were underprovided, with some such as maternity care providing less than half of what was required.</p> <p>The EHP was under-funded throughout the period covering on average 57% of necessary costs. By 2007/08 the funding paid by SWAp partners including the government of Malawi to fund the EHP was at US$13.5 per capita per annum, which was almost half of the revised EHP estimated required expenditure per capita per annum.</p> <p>Discussion</p> <p>The SWAp had invested in some very cost-effective health interventions. In terms of numbers of patients treated, the EHP had delivered two thirds of the services required. This was despite serious under-funding of the EHP, an increase in the population and shortage of staff.</p> <p>Conclusions</p> <p>The identification of interventions of proven effectiveness and good value for money and earmarked funding through a SWAp process can produce measurable improvement in health service delivery at extremely low cost.</p
Antibody tests for identification of current and past infection with SARS-CoV-2
Background
The diagnostic challenges associated with the COVIDâ19 pandemic resulted in rapid development of diagnostic test methods for detecting SARSâCoVâ2 infection. Serology tests to detect the presence of antibodies to SARSâCoVâ2 enable detection of past infection and may detect cases of SARSâCoVâ2 infection that were missed by earlier diagnostic tests. Understanding the diagnostic accuracy of serology tests for SARSâCoVâ2 infection may enable development of effective diagnostic and management pathways, inform public health management decisions and understanding of SARSâCoVâ2 epidemiology.
Objectives
To assess the accuracy of antibody tests, firstly, to determine if a person presenting in the community, or in primary or secondary care has current SARSâCoVâ2 infection according to time after onset of infection and, secondly, to determine if a person has previously been infected with SARSâCoVâ2. Sources of heterogeneity investigated included: timing of test, test method, SARSâCoVâ2 antigen used, test brand, and reference standard for nonâSARSâCoVâ2 cases.
Search methods
The COVIDâ19 Open Access Project living evidence database from the University of Bern (which includes daily updates from PubMed and Embase and preprints from medRxiv and bioRxiv) was searched on 30 September 2020. We included additional publications from the Evidence for Policy and Practice Information and Coâordinating Centre (EPPIâCentre) âCOVIDâ19: Living map of the evidenceâ and the Norwegian Institute of Public Health âNIPH systematic and living map on COVIDâ19 evidenceâ. We did not apply language restrictions.
Selection criteria
We included test accuracy studies of any design that evaluated commercially produced serology tests, targeting IgG, IgM, IgA alone, or in combination. Studies must have provided data for sensitivity, that could be allocated to a predefined time period after onset of symptoms, or after a positive RTâPCR test. Small studies with fewer than 25 SARSâCoVâ2 infection cases were excluded. We included any reference standard to define the presence or absence of SARSâCoVâ2 (including reverse transcription polymerase chain reaction tests (RTâPCR), clinical diagnostic criteria, and preâpandemic samples).
Data collection and analysis
We use standard screening procedures with three reviewers. Quality assessment (using the QUADASâ2 tool) and numeric study results were extracted independently by two people. Other study characteristics were extracted by one reviewer and checked by a second. We present sensitivity and specificity with 95% confidence intervals (CIs) for each test and, for metaâanalysis, we fitted univariate randomâeffects logistic regression models for sensitivity by eligible time period and for specificity by reference standard group. Heterogeneity was investigated by including indicator variables in the randomâeffects logistic regression models. We tabulated results by test manufacturer and summarised results for tests that were evaluated in 200 or more samples and that met a modification of UK Medicines and Healthcare products Regulatory Agency (MHRA) target performance criteria.
Main results
We included 178 separate studies (described in 177 study reports, with 45 as preâprints) providing 527 test evaluations. The studies included 64,688 samples including 25,724 from people with confirmed SARSâCoVâ2; most compared the accuracy of two or more assays (102/178, 57%). Participants with confirmed SARSâCoVâ2 infection were most commonly hospital inpatients (78/178, 44%), and preâpandemic samples were used by 45% (81/178) to estimate specificity. Over twoâthirds of studies recruited participants based on known SARSâCoVâ2 infection status (123/178, 69%). All studies were conducted prior to the introduction of SARSâCoVâ2 vaccines and present data for naturally acquired antibody responses. Seventyânine percent (141/178) of studies reported sensitivity by week after symptom onset and 66% (117/178) for convalescent phase infection. Studies evaluated enzymeâlinked immunosorbent assays (ELISA) (165/527; 31%), chemiluminescent assays (CLIA) (167/527; 32%) or lateral flow assays (LFA) (188/527; 36%).
Risk of bias was high because of participant selection (172, 97%); application and interpretation of the index test (35, 20%); weaknesses in the reference standard (38, 21%); and issues related to participant flow and timing (148, 82%). We judged that there were high concerns about the applicability of the evidence related to participants in 170 (96%) studies, and about the applicability of the reference standard in 162 (91%) studies.
Average sensitivities for current SARSâCoVâ2 infection increased by week after onset for all target antibodies. Average sensitivity for the combination of either IgG or IgM was 41.1% in week one (95% CI 38.1 to 44.2; 103 evaluations; 3881 samples, 1593 cases), 74.9% in week two (95% CI 72.4 to 77.3; 96 evaluations, 3948 samples, 2904 cases) and 88.0% by week three after onset of symptoms (95% CI 86.3 to 89.5; 103 evaluations, 2929 samples, 2571 cases). Average sensitivity during the convalescent phase of infection (up to a maximum of 100 days since onset of symptoms, where reported) was 89.8% for IgG (95% CI 88.5 to 90.9; 253 evaluations, 16,846 samples, 14,183 cases), 92.9% for IgG or IgM combined (95% CI 91.0 to 94.4; 108 evaluations, 3571 samples, 3206 cases) and 94.3% for total antibodies (95% CI 92.8 to 95.5; 58 evaluations, 7063 samples, 6652 cases). Average sensitivities for IgM alone followed a similar pattern but were of a lower test accuracy in every time slot.
Average specificities were consistently high and precise, particularly for preâpandemic samples which provide the least biased estimates of specificity (ranging from 98.6% for IgM to 99.8% for total antibodies).
Subgroup analyses suggested small differences in sensitivity and specificity by test technology however heterogeneity in study results, timing of sample collection, and smaller sample numbers in some groups made comparisons difficult. For IgG, CLIAs were the most sensitive (convalescentâphase infection) and specific (preâpandemic samples) compared to both ELISAs and LFAs (P < 0.001 for differences across test methods). The antigen(s) used (whether from the Spikeâprotein or nucleocapsid) appeared to have some effect on average sensitivity in the first weeks after onset but there was no clear evidence of an effect during convalescentâphase infection.
Investigations of test performance by brand showed considerable variation in sensitivity between tests, and in results between studies evaluating the same test. For tests that were evaluated in 200 or more samples, the lower bound of the 95% CI for sensitivity was 90% or more for only a small number of tests (IgG, n = 5; IgG or IgM, n = 1; total antibodies, n = 4). More test brands met the MHRA minimum criteria for specificity of 98% or above (IgG, n = 16; IgG or IgM, n = 5; total antibodies, n = 7). Seven assays met the specified criteria for both sensitivity and specificity.
In a lowâprevalence (2%) setting, where antibody testing is used to diagnose COVIDâ19 in people with symptoms but who have had a negative PCR test, we would anticipate that 1 (1 to 2) case would be missed and 8 (5 to 15) would be falsely positive in 1000 people undergoing IgG or IgM testing in week three after onset of SARSâCoVâ2 infection.
In a seroprevalence survey, where prevalence of prior infection is 50%, we would anticipate that 51 (46 to 58) cases would be missed and 6 (5 to 7) would be falsely positive in 1000 people having IgG tests during the convalescent phase (21 to 100 days postâsymptom onset or postâpositive PCR) of SARSâCoVâ2 infection.
Authors' conclusions
Some antibody tests could be a useful diagnostic tool for those in whom molecularâ or antigenâbased tests have failed to detect the SARSâCoVâ2 virus, including in those with ongoing symptoms of acute infection (from week three onwards) or those presenting with postâacute sequelae of COVIDâ19. However, antibody tests have an increasing likelihood of detecting an immune response to infection as time since onset of infection progresses and have demonstrated adequate performance for detection of prior infection for seroâepidemiological purposes. The applicability of results for detection of vaccinationâinduced antibodies is uncertain
Evidence for perinatal and child health care guidelines in crisis settings: can Cochrane help?
<p>Abstract</p> <p>Background</p> <p>It is important that healthcare provided in crisis settings is based on the best available research evidence. We reviewed guidelines for child and perinatal health care in crisis situations to determine whether they were based on research evidence, whether Cochrane systematic reviews were available in the clinical areas addressed by these guidelines and whether summaries of these reviews were provided in Evidence Aid.</p> <p>Methods</p> <p>Broad internet searches were undertaken to identify relevant guidelines. Guidelines were appraised using AGREE and the clinical areas that were relevant to perinatal or child health were extracted. We searched The Cochrane Database of Systematic Reviews to identify potentially relevant reviews. For each review we determined how many trials were included, and how many were conducted in resource-limited settings.</p> <p>Results</p> <p>Six guidelines met selection criteria. None of the included guidelines were clearly based on research evidence. 198 Cochrane reviews were potentially relevant to the guidelines. These reviews predominantly addressed nutrient supplementation, breastfeeding, malaria, maternal hypertension, premature labour and prevention of HIV transmission. Most reviews included studies from developing settings. However for large portions of the guidelines, particularly health services delivery, there were no relevant reviews. Only 18 (9.1%) reviews have summaries in Evidence Aid.</p> <p>Conclusions</p> <p>We did not identify any evidence-based guidelines for perinatal and child health care in disaster settings. We found many Cochrane reviews that could contribute to the evidence-base supporting future guidelines. However there are important issues to be addressed in terms of the relevance of the available reviews and increasing the number of reviews addressing health care delivery.</p