scholarly journals Response strategies for COVID-19 epidemics in African settings: a mathematical modelling study

BMC Medicine ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Kevin van Zandvoort ◽  
◽  
Christopher I. Jarvis ◽  
Carl A. B. Pearson ◽  
Nicholas G. Davies ◽  
...  

Abstract Background The health impact of COVID-19 may differ in African settings as compared to countries in Europe or China due to demographic, epidemiological, environmental and socio-economic factors. We evaluated strategies to reduce SARS-CoV-2 burden in African countries, so as to support decisions that balance minimising mortality, protecting health services and safeguarding livelihoods. Methods We used a Susceptible-Exposed-Infectious-Recovered mathematical model, stratified by age, to predict the evolution of COVID-19 epidemics in three countries representing a range of age distributions in Africa (from oldest to youngest average age: Mauritius, Nigeria and Niger), under various effectiveness assumptions for combinations of different non-pharmaceutical interventions: self-isolation of symptomatic people, physical distancing and ‘shielding’ (physical isolation) of the high-risk population. We adapted model parameters to better represent uncertainty about what might be expected in African populations, in particular by shifting the distribution of severity risk towards younger ages and increasing the case-fatality ratio. We also present sensitivity analyses for key model parameters subject to uncertainty. Results We predicted median symptomatic attack rates over the first 12 months of 23% (Niger) to 42% (Mauritius), peaking at 2–4 months, if epidemics were unmitigated. Self-isolation while symptomatic had a maximum impact of about 30% on reducing severe cases, while the impact of physical distancing varied widely depending on percent contact reduction and R0. The effect of shielding high-risk people, e.g. by rehousing them in physical isolation, was sensitive mainly to residual contact with low-risk people, and to a lesser extent to contact among shielded individuals. Mitigation strategies incorporating self-isolation of symptomatic individuals, moderate physical distancing and high uptake of shielding reduced predicted peak bed demand and mortality by around 50%. Lockdowns delayed epidemics by about 3 months. Estimates were sensitive to differences in age-specific social mixing patterns, as published in the literature, and assumptions on transmissibility, infectiousness of asymptomatic cases and risk of severe disease or death by age. Conclusions In African settings, as elsewhere, current evidence suggests large COVID-19 epidemics are expected. However, African countries have fewer means to suppress transmission and manage cases. We found that self-isolation of symptomatic persons and general physical distancing are unlikely to avert very large epidemics, unless distancing takes the form of stringent lockdown measures. However, both interventions help to mitigate the epidemic. Shielding of high-risk individuals can reduce health service demand and, even more markedly, mortality if it features high uptake and low contact of shielded and unshielded people, with no increase in contact among shielded people. Strategies combining self-isolation, moderate physical distancing and shielding could achieve substantial reductions in mortality in African countries. Temporary lockdowns, where socioeconomically acceptable, can help gain crucial time for planning and expanding health service capacity.

Author(s):  
Kevin van Zandvoort ◽  
Christopher I Jarvis ◽  
Carl A B Pearson ◽  
Nicholas G Davies ◽  
Timothy W Russell ◽  
...  

AbstractBackgroundThe health impact of COVID-19 may differ in African settings as compared to countries in Europe or China due to demographic, epidemiological, environmental and socio-economic factors. We evaluated strategies to reduce SARS-CoV-2 burden in African countries, so as to support decisions that balance minimising mortality, protecting health services and safeguarding livelihoods.MethodsWe used a Susceptible-Exposed-Infectious-Recovered mathematical model, stratified by age, to predict the evolution of COVID-19 epidemics in three countries representing a range of age distributions in Africa (from oldest to youngest average age: Mauritius, Nigeria and Niger), under various effectiveness assumptions for combinations of different non-pharmaceutical interventions: self-isolation of symptomatic people, physical distancing, and ‘shielding’ (physical isolation) of the high-risk population. We adapted model parameters to better represent uncertainty about what might be expected in African populations, in particular by shifting the distribution of severity risk towards younger ages and increasing the case-fatality ratio.ResultsWe predicted median clinical attack rates over the first 12 months of 17% (Niger) to 39% (Mauritius), peaking at 2–4 months, if epidemics were unmitigated. Self-isolation while symptomatic had a maximum impact of about 30% on reducing severe cases, while the impact of physical distancing varied widely depending on percent contact reduction and R0. The effect of shielding high-risk people, e.g. by rehousing them in physical isolation, was sensitive mainly to residual contact with low-risk people, and to a lesser extent to contact among shielded individuals. Response strategies incorporating self-isolation of symptomatic individuals, moderate physical distancing and high uptake of shielding reduced predicted peak bed demand by 46% to 54% and mortality by 60% to 75%. Lockdowns delayed epidemics by about 3 months. Estimates were sensitive to differences in age-specific social mixing patterns, as published in the literature.DiscussionIn African settings, as elsewhere, current evidence suggests large COVID-19 epidemics are expected. However, African countries have fewer means to suppress transmission and manage cases. We found that self-isolation of symptomatic persons and general physical distancing are unlikely to avert very large epidemics, unless distancing takes the form of stringent lockdown measures. However, both interventions help to mitigate the epidemic. Shielding of high-risk individuals can reduce health service demand and, even more markedly, mortality if it features high uptake and low contact of shielded and unshielded people, with no increase in contact among shielded people. Strategies combining self-isolation, moderate physical distancing and shielding will probably achieve substantial reductions in mortality in African countries. Temporary lockdowns, where socioeconomically acceptable, can help gain crucial time for planning and expanding health service capacity.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Maitri Kalra ◽  
Yan Tong ◽  
David R. Jones ◽  
Tom Walsh ◽  
Michael A. Danso ◽  
...  

AbstractPatients with triple-negative breast cancer (TNBC) who have residual disease after neoadjuvant therapy have a high risk of recurrence. We tested the impact of DNA-damaging chemotherapy alone or with PARP inhibition in this high-risk population. Patients with TNBC or deleterious BRCA mutation (TNBC/BRCAmut) who had >2 cm of invasive disease in the breast or persistent lymph node (LN) involvement after neoadjuvant therapy were assigned 1:1 to cisplatin alone or with rucaparib. Germline mutations were identified with BROCA analysis. The primary endpoint was 2-year disease-free survival (DFS) with 80% power to detect an HR 0.5. From Feb 2010 to May 2013, 128 patients were enrolled. Median tumor size at surgery was 1.9 cm (0–11.5 cm) with 1 (0–38) involved LN; median Residual Cancer Burden (RCB) score was 2.6. Six patients had known deleterious BRCA1 or BRCA2 mutations at study entry, but BROCA identified deleterious mutations in 22% of patients with available samples. Toxicity was similar in both arms. Despite frequent dose reductions (21% of patients) and delays (43.8% of patients), 73% of patients completed planned cisplatin. Rucaparib exposure was limited with median concentration 275 (82–4694) ng/mL post-infusion on day 3. The addition of rucaparib to cisplatin did not increase 2-year DFS (54.2% cisplatin vs. 64.1% cisplatin + rucaparib; P = 0.29). In the high-risk post preoperative TNBC/BRCAmut setting, the addition of low-dose rucaparib did not improve 2-year DFS or increase the toxicity of cisplatin. Genetic testing was underutilized in this high-risk population.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ausenda Machado ◽  
Irina Kislaya ◽  
Amparo Larrauri ◽  
Carlos Matias Dias ◽  
Baltazar Nunes

Abstract Background All aged individuals with a chronic condition and those with 65 and more years are at increased risk of severe influenza post-infection complications. There is limited research on cases averted by the yearly vaccination programs in high-risk individuals. The objective was to estimate the impact of trivalent seasonal influenza vaccination on averted hospitalizations and death among the high-risk population in Portugal. Methods The impact of trivalent seasonal influenza vaccination was estimated using vaccine coverage, vaccine effectiveness and the number of influenza-related hospitalizations and deaths. The number of averted events (NAE), prevented fraction (PF) and number needed to vaccinate (NVN) were estimated for seasons 2014/15 to 2016/17. Results The vaccination strategy averted on average approximately 1833 hospitalizations and 383 deaths per season. Highest NAE was observed in the ≥65 years population (85% of hospitalizations and 95% deaths) and in the 2016/17 season (1957 hospitalizations and 439 deaths). On average, seasonal vaccination prevented 21% of hospitalizations in the population aged 65 and more, and 18.5% in the population with chronic conditions. The vaccination also prevented 29% and 19.5% of deaths in each group of the high-risk population. It would be needed to vaccinate 3360 high-risk individuals, to prevent one hospitalization and 60,471 high-risk individuals to prevent one death. Conclusion The yearly influenza vaccination campaigns had a sustained positive benefit for the high-risk population, reducing hospitalizations and deaths. These results can support public health plans toward increased vaccine coverage in high-risk groups.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Maheer Gandhavadi ◽  
Kendrick A Shunk ◽  
Edward J McNulty

Background Data regarding the impact of drug eluting stent (DES) use on long-term outcomes outside trial populations are limited. Methods 1,547 consecutive patients underwent stent implantation from January 2000 until December 2006 at the San Francisco Veterans Affairs Medical Center. To assess the impact of DES availability on mortality, that population was partitioned into a pre-DES cohort (N=591) and a post-DES availability cohort (N=956). Kaplan-Meier survival curves for the two cohorts were compared. Results The entire population was relatively high risk: 37% had diabetes, 38% a reduced ejection fraction, and 53% a prior MI or elevated troponin prior to the procedure. Median follow up was 4.7 years for the pre-DES cohort and 1.8 years for the post-DES cohort. DES were used in 83% of procedures in the post-DES cohort. Survival improved significantly in the post-DES cohort (P = .04, Log Rank)(see Figure ). Baseline characteristics, procedural variables and discharge medications were analyzed in a Cox proportional hazards model (see Table ). DES use was an independent predictor of improved survival (Hazard Ratio for death 0.52, 95% CI .28–.95). Conclusions In an unselected, high risk population, long-term survival improved following the availability of drug eluting stents. After adjusting for potential confounding factors, DES use was an independent predictor of improved survival. Independent Predictors of Death in all 1,547 Patients


Open Heart ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. e001037 ◽  
Author(s):  
Claudia I Rinciog ◽  
Laura M Sawyer ◽  
Alexander Diamantopoulos ◽  
Mitchell S V Elkind ◽  
Matthew Reynolds ◽  
...  

ObjectiveTo evaluate the cost-effectiveness of insertable cardiac monitors (ICMs) compared with standard of care (SoC) for detecting atrial fibrillation (AF) in patients at high risk of stroke (CHADS2 >2), using a UK National Health Service (NHS) perspective.MethodsUsing patient characteristics and clinical data from the REVEAL AF trial, a Markov model assessed the cost-effectiveness of detecting AF with an ICM compared with SoC. Costs and benefits were extrapolated across modelled patient lifetime. Ischaemic and haemorrhagic strokes, intracranial and extracranial haemorrhages and minor bleeds were modelled. Diagnostic and device costs were included, plus costs of treating stroke and bleeding events and costs of oral anticoagulants (OACs). Costs and health outcomes, measured as quality-adjusted life years (QALYs), were discounted at 3.5% per annum. One-way deterministic and probabilistic sensitivity analyses (PSA) were undertaken.ResultsThe total per-patient cost for ICM was £13 360 versus £11 936 for SoC (namely, annual 24 hours Holter monitoring). ICMs generated a total of 6.50 QALYs versus 6.30 for SoC. The incremental cost-effectiveness ratio (ICER) was £7140/QALY gained, below the £20 000/QALY acceptability threshold. ICMs were cost-effective in 77.4% of PSA simulations. The number of ICMs needed to prevent one stroke was 21 and to cause a major bleed was 37. ICERs were sensitive to assumed proportions of patients initiating or discontinuing OAC after AF diagnosis, type of OAC used and how intense the traditional monitoring was assumed to be under SoC.ConclusionsThe use of ICMs to identify AF in a high-risk population is cost-effective for the UK NHS.


2017 ◽  
Vol 35 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Caroline G. Watts ◽  
Anne E. Cust ◽  
Scott W. Menzies ◽  
Graham J. Mann ◽  
Rachael L. Morton

Purpose Clinical guidelines recommend that people at high risk of melanoma receive regular surveillance to improve survival through early detection. A specialized High Risk Clinic in Sydney, Australia was found to be effective for this purpose; however, wider implementation of this clinical service requires evidence of cost-effectiveness and data addressing potential overtreatment of suspicious skin lesions. Patients and Methods A decision-analytic model was built to compare the costs and benefits of specialized surveillance compared with standard care over a 10-year period, from a health system perspective. A high-risk standard care cohort was obtained using linked population data, comprising the Sax Institute’s 45 and Up cohort study, linked to Medicare Benefits Schedule claims data, the cancer registry, and hospital admissions data. Benefits were measured in quality-adjusted life-years gained. Sensitivity analyses were undertaken for all model parameters. Results Specialized surveillance through the High Risk Clinic was both less expensive and more effective than standard care. The mean saving was A$6,828 (95% CI, $5,564 to $8,092) per patient, and the mean quality-adjusted life-year gain was 0.31 (95% CI, 0.27 to 0.35). The main drivers of the differences were detection of melanoma at an earlier stage resulting in less extensive treatment and a lower annual mean excision rate for suspicious lesions in specialized surveillance (0.81; 95% CI, 0.72 to 0.91) compared with standard care (2.55; 95% CI, 2.34 to 2.76). The results were robust when tested in sensitivity analyses. Conclusion Specialized surveillance was a cost-effective strategy for the management of individuals at high risk of melanoma. There were also fewer invasive procedures in specialized surveillance compared with standard care in the community.


2013 ◽  
Vol 31 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Adam N. Rosenthal ◽  
Lindsay Fraser ◽  
Ranjit Manchanda ◽  
Philip Badman ◽  
Susan Philpott ◽  
...  

Purpose To establish the performance characteristics of annual transvaginal ultrasound and serum CA125 screening for women at high risk of ovarian/fallopian tube cancer (OC/FTC) and to investigate the impact of delayed screening interval and surgical intervention. Patients and Methods Between May 6, 2002, and January 5, 2008, 3,563 women at an estimated ≥ 10% lifetime risk of OC/FTC were recruited and screened by 37 centers in the United Kingdom. Participants were observed prospectively by centers, questionnaire, and national cancer registries. Results Sensitivity for detection of incident OC/FTC at 1 year after last annual screen was 81.3% (95% CI, 54.3% to 96.0%) if occult cancers were classified as false negatives and 87.5% (95% CI, 61.7% to 98.5%) if they were classified as true positives. Positive and negative predictive values of incident screening were 25.5% (95% CI, 14.3 to 40.0) and 99.9% (95% CI, 99.8 to 100) respectively. Four (30.8%) of 13 incident screen-detected OC/FTCs were stage I or II. Compared with women screened in the year before diagnosis, those not screened in the year before diagnosis were more likely to have ≥ stage IIIc disease (85.7% v 26.1%; P = .009). Screening interval was delayed by a median of 88 days before detection of incident OC/FTC. Median interval from detection screen to surgical intervention was 79 days in prevalent and incident OC/FTC. Conclusion These results in the high-risk population highlight the need for strict adherence to screening schedule. Screening more frequently than annually with prompt surgical intervention seems to offer a better chance of early-stage detection.


10.2196/25581 ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. e25581
Author(s):  
Siddharth Rele ◽  
Cade Shadbolt ◽  
Chris Schilling ◽  
Nicholas F Taylor ◽  
Michelle M Dowsey ◽  
...  

Background The number of total joint arthroplasties (TJAs) being performed is increasing worldwide. To match this increasing demand, there has been focus on hastening patients’ recovery of function. This effort has culminated in the formulation of enhanced recovery after surgery (ERAS) strategies. However, with evolving ERAS programs and new recommendations, a review of current evidence is required to provide clinicians with up-to-date information about its effect on outcomes for TJA. Objective The objective of this study is to assess the utility of ERAS programs on patient, health service, and economic outcomes for primary, elective total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods A systematic search will be conducted in Medline (Ovid), EMCARE (Ovid), EMBASE (Ovid), Web of Science, CINAHL, National Health Service Economic Evaluations Database, and the Cochrane Library. Analytical, observational, and experimental designs will be included in this systematic review. Only studies including patients undergoing primary TKA and THA comparing ERAS programs with conventional surgery and postoperative care will be included. Data related to patient outcomes, health service outcomes, safety, and economic evaluation will be extracted. Results The search terms and primary database searches have been finalized. Findings will be reported in narrative and tabular form. Where appropriate, random effects meta-analyses will be conducted for each outcome, and heterogeneity quantified with Cochran Q test and I2 statistic. Measures of effect or mean differences will be reported with 95% confidence intervals. The results of this systematic review will be disseminated in a peer-reviewed journal. Conclusions This protocol will guide a systematic review assessing outcomes associated with ERAS surgery in primary THA and TKA. Trial Registration Open Science Framework osf.io/y4bhs; https://osf.io/y4bhs International Registered Report Identifier (IRRID) PRR1-10.2196/25581


2021 ◽  
pp. 533-542
Author(s):  
Samantha E. Greenberg ◽  
Trevor C. Hunt ◽  
Jacob P. Ambrose ◽  
William T. Lowrance ◽  
Christopher B. Dechet ◽  
...  

PURPOSE Germline likely pathogenic or pathogenic variants (PVs) have been identified in up to 17% of men with prostate cancer (PC) and may drive disease severity or be targetable by novel therapies. National Comprehensive Cancer Network (NCCN) guidelines encouraging germline testing in metastatic PC were recently expanded to include all men with high-risk, very high-risk, or regional PC. Our aim was to assess the impact of expanded NCCN guidelines on the detection rate of germline PVs and to determine patient-level factors associated with a PV germline testing result. PATIENTS AND METHODS Men with PC underwent multigene germline genetic testing for PVs from June 2016 to December 2018, and trends were compared. The association of patient-level factors with a PV germline testing result, where ≥ 1 PV was identified, was assessed using analysis of variance and univariate logistic regression. Sensitivity analyses were limited to clinically actionable variants and those associated with disease severity or progression ( BRCA1/2 and ATM). RESULTS Of 408 men undergoing germline testing, 42 (10.3%) men had PVs and 366 (89.7%) men did not have PVs identified. The proportion of men identified with a germline PV remained stable following testing criteria expansion (9.4% v 10.6%, P = .73). No patient-level factors were significantly associated with increased odds of a PV germline testing result, including age at diagnosis, race, pretreatment prostate-specific antigen, Gleason grade group, NCCN risk group, and family history of cancer (breast and/or ovarian, prostate, or any cancer). CONCLUSION This study demonstrated a stable PV detection rate in men with PC using expanded criteria aligned to the updated NCCN testing guidelines. However, we did not find strong evidence to suggest that patient-level factors are associated with PV germline testing results. These findings support the recent expansion of NCCN germline testing guidelines in PC.


2021 ◽  
Author(s):  
Emeka Okafor ◽  
Brad Bass

Abstract The spread of infectious diseases such as COVID-19 in a typical oil and gas facility setting, the health of employees, their families and their communities, is of real concern to the industry. In this work, a suitable predictive, agent-based model is used to predict the spread of COVID-19 in different settings as well as to evaluate strategies to block the spread. The agent-based modelling work is based on the simulation platform, Complex Organization and Bifurcation Within Environmental Bounds, or COBWEB. COBWEB simulates how a system of autonomous agents adapts to variation and sudden changes in the resource base or other features of their environment. Previous COBWEB simulation results illustrate that the tool is useful for predicting the evolution of COVID-19 spread and the effectiveness of various preventive actions including self-isolation of symptomatic people, social/physical distancing, effective PPE use, and ‘shielding’ (physical isolation) of the high-risk population. We adapted model parameters to better represent uncertainty about what might be expected in such a setting, in particular by shifting the distribution of risk severity towards ineffective PPE use, self-isolation and poor social distancing, which expectedly shows upward trend of the spread of the COVID-19. Ultimately, governments and industry can apply the predicted trends, as well as apply the model to specific settings, to make more informed decisions on the additional measures and preventative strategies to curb the spread of COVID-19.


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