Imperial College London

DrShevanthiNayagam

Faculty of MedicineSchool of Public Health

Clinical Fellow
 
 
 
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s.nayagam01

 
 
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Medical SchoolSt Mary's Campus

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Summary

 

Publications

Publication Type
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63 results found

Echeverria-Londono S, Li X, Toor J, de Villiers MJ, Nayagam S, Hallett TB, Abbas K, Jit M, Klepac P, Jean K, Garske T, Ferguson NM, Gaythorpe KAMet al., 2021, How can the public health impact of vaccination be estimated?, BMC PUBLIC HEALTH, Vol: 21

Journal article

Christen P, D'Aeth J, Lochen A, McCabe R, Rizmie D, Schmit N, Nayagam S, Miraldo M, Aylin P, Bottle A, Perez Guzman P, Donnelly C, Ghani A, Ferguson N, White P, Hauck Ket al., 2021, The J-IDEA pandemic planner: a framework for implementing hospital provision interventions during the COVID-19 pandemic, Medical Care, Vol: 59, Pages: 371-378, ISSN: 0025-7079

Background : Planning for extreme surges in demand for hospital care of patientsrequiring urgent life-saving treatment for COVID-19, whilst retaining capacity for otheremergency conditions, is one of the most challenging tasks faced by healthcareproviders and policymakers during the pandemic. Health systems must be wellpreparedto cope with large and sudden changes in demand by implementinginterventions to ensure adequate access to care. We developed the first planning toolfor the COVID-19 pandemic to account for how hospital provision interventions (suchas cancelling elective surgery, setting up field hospitals, or hiring retired staff) will affectthe capacity of hospitals to provide life-saving care.Methods : We conducted a review of interventions implemented or considered in 12 European countries in March-April 2020, an evaluation of their impact on capacity, anda review of key parameters in the care of COVID-19 patients. This information wasused to develop a planner capable of estimating the impact of specific interventions ondoctors, nurses, beds and respiratory support equipment. We applied this to ascenario-based case study of one intervention, the set-up of field hospitals in England,under varying levels of COVID-19 patients.Results : The J-IDEA pandemic planner is a hospital planning tool that allows hospitaladministrators, policymakers and other decision-makers to calculate the amount ofcapacity in terms of beds, staff and crucial medical equipment obtained byimplementing the interventions. Flexible assumptions on baseline capacity, the numberof hospitalisations, staff-to-beds ratios, and staff absences due to COVID-19 make theplanner adaptable to multiple settings. The results of the case study show that whilefield hospitals alleviate the burden on the number of beds available, this intervention isfutile unless the deficit of critical care nurses is addressed first.Discussion : The tool supports decision-makers in delivering a fast and effectiveresponse to

Journal article

Schmit N, Nayagam S, Thursz M, Hallett Tet al., 2021, The global burden of chronic hepatitis B virus infection: comparison of country-level prevalence estimates from four research groups, International Journal of Epidemiology, Vol: 50, Pages: 560-569, ISSN: 0300-5771

Background: Progress towards viral hepatitis elimination goals relies on accurate estimates of chronic hepatitis B virus (HBV) infection prevalence. We compared existing sources of the most recent country-level estimates from 2013-2017 to investigate the extent and underlying drivers of differences between them. Methods: The four commonly cited sources of global prevalence estimates, the Institute for Health Metrics and Evaluation, Schweitzer et al, World Health Organization (WHO) and CDA Foundation, were compared by calculating pairwise differences between sets of estimates and assessing their within-country variation. Differences in underlying empirical data and modelling methods were investigated as contributors to differences in sub-Saharan African estimates. Results: The four sets of estimates across all ages were comparable overall and agreed on the global distribution of HBV burden. WHO and CDA produced the most similar estimates, differing by a median of 0.8 percentage points. Larger discrepancies were seen in estimates of prevalence in children under 5 years of age and in sub-Saharan African countries, where the median pairwise differences were 2.7 and 2.4 percentage points for all age prevalence and in children, respectively. Recency and representativeness of included data, and different modelling assumptions of the age distribution of HBV burden, seemed to contribute to these differences. Conclusion: Current prevalence estimates, particularly those from WHO and CDA based on more recent empirical data, provide a useful resource to assess the population-level burden of chronic HBV infection. However, further seroprevalence data in young children is needed particularly in sub-Saharan Africa. This is a priority as monitoring progress towards elimination depends on improved knowledge of prevalence in this age group.

Journal article

Nayagam AS, Chan P, Zhao K, Sicuri E, Wang X, Jia J, Wei L, Walsh N, Rodewald LE, Zhang G, Ailing W, Zhang L, Chang J, Hou C, Qiu Y, Sui B, Xiao Y, Zhuang H, Thursz M, Scano F, Low-Beer D, Schwartländer B, Wang Y, Hallett TBet al., 2021, Investment case for a comprehensive package of interventions against Hepatitis B in China; applied modelling to help national strategy planning, Clinical Infectious Diseases, Vol: 72, Pages: 743-752, ISSN: 1058-4838

Background:In2016,the first globalviralhepatitiselimination targetswere endorsed. Anestimated one-third of the world’schronic HBV infected population live in China and liver cancer is the sixth leading cause of mortality, but coverage of first line antiviral treatment was low. In 2015, China was one of the first countriesto initiate a consultative process for a renewed approach to viral hepatitis. We present the investment case for the scale-up of a comprehensive package of HBV interventions. Methods:Adynamic simulation modelof HBV was developedand used to simulate the Chinese HBV epidemic. We evaluated the impact, costs and return on investment of a comprehensive package of prevention and treatment interventions from a societal perspective, incorporating costs of management of end-stage liver disease and lost productivity costs. Results:Despitethe successes of historical vaccination scale-up since 1992, there will be a projected 60millionpeople still living with HBV in 2030 and 10 million HBV-related deaths, including 5.7millionHBV-related cancer deaths between 2015-2030. This could be reduced by 2.1million by highly active case-finding and optimal antiviral treatment regimens. The package of interventions is likely to have a positive return-on-investment to society, of 1.57US$ per US$ invested. Conclusions:Increases in HBV-related deaths for the next few decades pose a major public health threatin China. Active case-finding and access to optimal antiviral treatment is requiredto mitigate this risk. This investment case approachprovides a real-world example of howapplied modellingcansupportnational dialogue and inform policy planning.

Journal article

Li X, Mukandavire C, Cucunuba ZM, Londono SE, Abbas K, Clapham HE, Jit M, Johnson HL, Papadopoulos T, Vynnycky E, Brisson M, Carter ED, Clark A, de Villiers MJ, Eilertson K, Ferrari MJ, Gamkrelidze I, Gaythorpe KAM, Grassly NC, Hallett TB, Hinsley W, Jackson ML, Jean K, Karachaliou A, Klepac P, Lessler J, Li X, Moore SM, Nayagam S, Duy MN, Razavi H, Razavi-Shearer D, Resch S, Sanderson C, Sweet S, Sy S, Tam Y, Tanvir H, Quan MT, Trotter CL, Truelove S, van Zandvoort K, Verguet S, Walker N, Winter A, Woodruff K, Ferguson NM, Garske Tet al., 2021, Estimating the health impact of vaccination against ten pathogens in 98 low-income and middle-income countries from 2000 to 2030: a modelling study, The Lancet, Vol: 397, Pages: 398-408, ISSN: 0140-6736

BackgroundThe past two decades have seen expansion of childhood vaccination programmes in low-income and middle-income countries (LMICs). We quantify the health impact of these programmes by estimating the deaths and disability-adjusted life-years (DALYs) averted by vaccination against ten pathogens in 98 LMICs between 2000 and 2030.Methods16 independent research groups provided model-based disease burden estimates under a range of vaccination coverage scenarios for ten pathogens: hepatitis B virus, Haemophilus influenzae type B, human papillomavirus, Japanese encephalitis, measles, Neisseria meningitidis serogroup A, Streptococcus pneumoniae, rotavirus, rubella, and yellow fever. Using standardised demographic data and vaccine coverage, the impact of vaccination programmes was determined by comparing model estimates from a no-vaccination counterfactual scenario with those from a reported and projected vaccination scenario. We present deaths and DALYs averted between 2000 and 2030 by calendar year and by annual birth cohort.FindingsWe estimate that vaccination of the ten selected pathogens will have averted 69 million (95% credible interval 52–88) deaths between 2000 and 2030, of which 37 million (30–48) were averted between 2000 and 2019. From 2000 to 2019, this represents a 45% (36–58) reduction in deaths compared with the counterfactual scenario of no vaccination. Most of this impact is concentrated in a reduction in mortality among children younger than 5 years (57% reduction [52–66]), most notably from measles. Over the lifetime of birth cohorts born between 2000 and 2030, we predict that 120 million (93–150) deaths will be averted by vaccination, of which 58 million (39–76) are due to measles vaccination and 38 million (25–52) are due to hepatitis B vaccination. We estimate that increases in vaccine coverage and introductions of additional vaccines will result in a 72% (59–81) reduction in lifetime mortality in t

Journal article

Middleton P, Perez-Guzman PN, Cheng A, Kumar N, Kont M, Daunt A, Mukherjee S, Cooke G, Hallett TB, Hauck K, White PJ, Thursz MR, Nayagam Set al., 2021, Characteristics and outcomes of clinically diagnosed RT-PCR swab negative COVID-19: a retrospective cohort study, Scientific Reports, Vol: 11, Pages: 1-7, ISSN: 2045-2322

Patients with strong clinical features of COVID-19 with negative real time polymerase chain reaction (RT-PCR) SARS-CoV-2 testing are not currently included in official statistics. The scale, characteristics and clinical relevance of this group are not well described. We performed a retrospective cohort study in two large London hospitals to characterize the demographic, clinical, and hospitalization outcome characteristics of swab-negative clinical COVID-19 patients. We found 1 in 5 patients with a negative swab and clinical suspicion of COVID-19 received a clinical diagnosis of COVID-19 within clinical documentation, discharge summary or death certificate. We compared this group to a similar swab positive cohort and found similar demographic composition, symptomology and laboratory findings. Swab-negative clinical COVID-19 patients had better outcomes, with shorter length of hospital stay, reduced need for >60% supplementary oxygen and reduced mortality. Patients with strong clinical features of COVID-19 that are swab-negative are a common clinical challenge. Health systems must recognize and plan for the management of swab-negative patients in their COVID-19 clinical management, infection control policies and epidemiological assessments.

Journal article

Heffernan A, Ma Y, Nayagam S, Chan P, Chen Z, Cooke GS, Guo Y, Liu C, Thursz M, Zhang W, Zhang X, Zhang X, Jia M, Hallett TBet al., 2021, Economic and epidemiological evaluation of interventions to reduce the burden of hepatitis C in Yunnan province, China, PLoS One, Vol: 16, Pages: 1-17, ISSN: 1932-6203

BackgroundThe paradigm shift in hepatitis C virus (HCV) treatment options in the last five years has raised the prospect of eliminating the disease as a global health threat. This will require a step-change in the number being treated with the new direct-acting antivirals (DAAs). Given constrained budgets and competing priorities, policy makers need information on how to scale-up access to HCV treatment. To inform such decisions, we examined the cost effectiveness of screening and treatment interventions in Yunnan, China.Methods and findingsWe simulated the HCV epidemic using a previously published model of HCV transmission and disease progression, calibrated to Yunnan data, and implemented a range of treatment and screening interventions from 2019. We incorporated treatment, diagnosis, and medical costs (expressed in 2019 US Dollars, USD) to estimate the lifetime benefits and costs of interventions. Using this model, we asked: is introducing DAAs cost effective from a healthcare sector perspective; what is the optimal combination of screening interventions; and what is the societal return on investment of intervention? The incremental cost-effectiveness ratio (ICER) of switching to DAAs with a median cost of 7,400 USD (50,000 Chinese Yuan) per course is 500 USD/disability adjusted life year (DALY) averted; at a threshold of 50% of Yunnan gross domestic product (2,600 USD), switching to DAAs is cost effective 94% of the time. At this threshold, the optimal, cost-effective intervention comprises screening people who inject drugs, those in HIV care, men who have sex with men, and ensuring access to DAAs for all those newly diagnosed with HCV. For each USD invested in this intervention, there is an additional 0·80 USD (95% credible interval: 0·17–1·91) returned through reduced costs of disease or increased productivity. Returns on investment are lower (and potentially negative) if a sufficiently long-term horizon, encompassing the full stream

Journal article

Londono SE, Li X, Toor J, Villiers MJD, Nayagam S, Hallett TB, Abbas K, Jit M, Klepac P, Jean K, Garske T, Ferguson NM, Gaythorpe KAMet al., 2021, How can the public health impact of vaccination be estimated?

<jats:title>ABSTRACT</jats:title><jats:p>Deaths due to vaccine preventable diseases cause a notable proportion of mortality worldwide. To quantify the importance of vaccination, it is necessary to estimate the burden averted through vaccination. The Vaccine Impact Modelling Consortium (VIMC) was established to estimate the health impact of vaccination. We describe the methods implemented by the VIMC to estimate impact by calendar year, birth year and year of vaccination (YoV). The calendar and birth year methods estimate impact in a particular year and over the lifetime of a particular birth cohort, respectively. The YoV method estimates the impact of a particular year’s vaccination activities through the use of impact ratios which have no stratification and stratification by activity type and/or birth cohort. Furthermore, we detail an impact extrapolation (IE) method for use between coverage scenarios. We compare the methods, focusing on YoV for hepatitis B, measles and yellow fever. We find that the YoV methods estimate similar impact with routine vaccinations but have greater yearly variation when campaigns occur with the birth cohort stratification. The IE performs well for the YoV methods, providing a time-efficient mechanism for updates to impact estimates. These methods provide a robust set of approaches to quantify vaccination impact.</jats:p>

Journal article

Hui Z, Nayagam S, Chan P, Fuzhen W, Thursz M, Zundong Y, Ning M, Xiaojin S, Cui F, Guomin Z, Hallett TBet al., 2021, Progress towards elimination of mother-to-child transmission of hepatitis B virus infection in China: a modelling analysis., Bulletin of the World Health Organization, Vol: 99, Pages: 10-18, ISSN: 0042-9686

Objective: To determine the projected burden of hepatitis B virus (HBV) in China, the intervention strategies that can eliminate mother-to-child transmission (MTCT) by 2030 or earlier and the measurable parameters that can be used to monitor progress towards this target. Methods: We developed a dynamic, sex- and age-stratified model of the HBV epidemic in China, calibrated using hepatitis B surface antigen (HBsAg) and e antigen (HBeAg) prevalence data from sequential national serosurveys (1979-2014) and the numbers of HBV-related cancer deaths (2012). We determined whether China can achieve elimination of MTCT of HBV by 2030 under current prevention interventions. We modelled various intervention scenarios to represent different coverage levels of birth-dose HBV vaccination, hepatitis B immunoglobulin to newborns of HBsAg-positive mothers and antiviral therapy (tenofovir) to HBeAg-positive pregnant women. Findings: We project that, if current levels of prevention interventions are maintained, China will achieve the elimination target by 2029. By modelling various intervention scenarios, we found that this can be brought forward to 2025 by increasing coverage of birth-dose vaccination, or to 2024 by the administration of tenofovir to HBeAg-positive pregnant women. We found that achievement of the target by 2025 would be predicted by a measurement of less than 2% MTCT in 2020. Conclusion: Our results highlight how high-quality national data can be combined with modelling in monitoring the elimination of MTCT of HBV. By demonstrating the impact of increased interventions on target achievement dates, we anticipate that other high-burden countries will be motivated to strengthen HBV prevention policies.

Journal article

Daunt A, Perez-Guzman PN, Cafferkey J, Manalan K, Cooke G, White PJ, Hauck K, Mallia P, Nayagam Set al., 2020, Factors associated with reattendance to emergency services following COVID-19 hospitalization, Journal of Medical Virology, Vol: 93, Pages: 1250-1252, ISSN: 0146-6615

Journal article

McCabe R, Schmit N, Christen P, D'Aeth J, Løchen A, Rizmie D, Nayagam AS, Miraldo M, Aylin P, Bottle R, Perez-Guzman PN, Ghani A, Ferguson N, White P, Hauck Ket al., 2020, Adapting hospital capacity to meet changing demands during the COVID-19 pandemic, BMC Medicine, Vol: 18, Pages: 1-12, ISSN: 1741-7015

BackgroundTo calculate hospital surge capacity, achieved via hospital provision interventions implemented for the emergency treatment of coronavirus disease 2019 (COVID-19) and other patients through March to May 2020; to evaluate the conditions for admitting patients for elective surgery under varying admission levels of COVID-19 patients.MethodsWe analysed National Health Service (NHS) datasets and literature reviews to estimate hospital care capacity before the pandemic (pre-pandemic baseline) and to quantify the impact of interventions (cancellation of elective surgery, field hospitals, use of private hospitals, deployment of former medical staff and deployment of newly qualified medical staff) for treatment of adult COVID-19 patients, focusing on general and acute (G&A) and critical care (CC) beds, staff and ventilators.ResultsNHS England would not have had sufficient capacity to treat all COVID-19 and other patients in March and April 2020 without the hospital provision interventions, which alleviated significant shortfalls in CC nurses, CC and G&A beds and CC junior doctors. All elective surgery can be conducted at normal pre-pandemic levels provided the other interventions are sustained, but only if the daily number of COVID-19 patients occupying CC beds is not greater than 1550 in the whole of England. If the other interventions are not maintained, then elective surgery can only be conducted if the number of COVID-19 patients occupying CC beds is not greater than 320. However, there is greater national capacity to treat G&A patients: without interventions, it takes almost 10,000 G&A COVID-19 patients before any G&A elective patients would be unable to be accommodated.ConclusionsUnless COVID-19 hospitalisations drop to low levels, there is a continued need to enhance critical care capacity in England with field hospitals, use of private hospitals or deployment of former and newly qualified medical staff to allow some or all elective surge

Journal article

Forlano R, Mullish BH, Mukherjee SK, Nathwani R, Harlow C, Crook P, Judge R, Soubieres A, Middleton P, Daunt A, Perez-Guzman P, Selvapatt N, Lemoine M, Dhar A, Thursz MR, Nayagam S, Manousou Pet al., 2020, In-hospital mortality is associated with inflammatory response in NAFLD patients admitted for COVID-19, PLoS One, Vol: 15, ISSN: 1932-6203

Background & aimsAlthough metabolic risk factors are associated with more severe COVID-19, there is little evidence on outcomes in patients with non-alcoholic fatty liver disease (NAFLD). We here describe the clinical characteristics and outcomes of NAFLD patients in a cohort hospitalised for COVID-19.MethodsThis study included all consecutive patients admitted for COVID-19 between February and April 2020 at Imperial College Healthcare NHS Trust, with either imaging of the liver available dated within one year from the admission or a known diagnosis of NAFLD. Clinical data and early weaning score (EWS) were recorded. NAFLD diagnosis was based on imaging or past medical history and patients were stratified for Fibrosis-4 (FIB-4) index. Clinical endpoints were admission to intensive care unit (ICU)and in-hospital mortality.Results561 patients were admitted. Overall, 193 patients were included in the study. Fifty nine patients (30%) died, 9 (5%) were still in hospital, and 125 (65%) were discharged. The NAFLD cohort (n = 61) was significantly younger (60 vs 70.5 years, p = 0.046) at presentation compared to the non-NAFLD (n = 132). NAFLD diagnosis was not associated with adverse outcomes. However, the NAFLD group had higher C reactive protein (CRP) (107 vs 91.2 mg/L, p = 0.05) compared to non-NAFLD(n = 132). Among NAFLD patients, male gender (p = 0.01), ferritin (p = 0.003) and EWS (p = 0.047) were associated with in-hospital mortality, while the presence of intermediate/high risk FIB-4 or liver cirrhosis was not.ConclusionThe presence of NAFLD per se was not associated with worse outcomes in patients hospitalised for COVID-19. Though NAFLD patients were younger on admission, disease stage was not associated with clinical outcomes. Yet, mortality was associated with gender and a pronounced inflammatory response in the NAFLD group.

Journal article

Forlano R, Mullish B, Mukherjee S, Nathwani R, Harlow C, Crook P, Judge R, Soubieres A, Middleton P, Daunt A, Perez Guzman P, Selvapatt N, Lemoine M, Dhar A, Thursz MR, Nayagam S, Manousou Pet al., 2020, 450 - In-hospital mortality is associated with inflammatory response in NAFLD patients admitted for COVID-19, Hepatology, Vol: 72, Pages: 282A-283A, ISSN: 0270-9139

Journal article

Daunt A, Perez-Guzman PN, Liew F, Hauck K, Costelloe CE, Thursz MR, Cooke G, Nayagam Set al., 2020, Validity of the UK early access to medicines scheme criteria for Remdesivir use in patients with COVID-19 disease, Journal of Infection, Vol: 81, Pages: 666-668, ISSN: 0163-4453

Journal article

Lazarus JV, Picchio CA, Nayagam S, Ratzan S, Thursz Met al., 2020, Strengthening vaccine confidence during the COVID-19 pandemic: A new opportunity for global hepatitis B virus elimination, JOURNAL OF HEPATOLOGY, Vol: 73, Pages: 490-492, ISSN: 0168-8278

Journal article

de Villiers MJ, Gamkrelidze I, Hallett TB, Nayagam S, Razavi H, Razavi-Shearer Det al., 2020, Modelling hepatitis B virus infection and impact of timely birth dose vaccine: A comparison of two simulation models, PLoS One, Vol: 15, Pages: 1-16, ISSN: 1932-6203

Hepatitis B is a global epidemic that requires carefully orchestrated vaccination initiatives in geographical regions of medium to high endemicity to reach the World Health Organization’s elimination targets by 2030. This study compares two widely-used deterministic hepatitis B models—the Imperial HBV model and the CDA Foundation’s PRoGReSs—based on their predicted outcomes in four countries. The impact of scaling up of the timely birth dose of the hepatitis B vaccine is also investigated. The two models predicted largely similar outcomes for the impact of vaccination programmes on the projected numbers of new cases and deaths under high levels of the infant hepatitis B vaccine series. However, scenarios for the scaling up of the infant hepatitis B vaccine series had a larger impact in the PRoGReSs model than in the Imperial model due to the infant vaccine series directly leading to the reduction of perinatal transmission in the PRoGReSs model, but not in the Imperial model. Meanwhile, scaling up of the timely birth dose vaccine had a greater impact on the outcomes of the Imperial hepatitis B model than in the PRoGReSs model due to the greater protection that the birth dose vaccine confers to infants in the Imperial model compared to the PRoGReSs model. These differences underlie the differences in projections made by the models under some circumstances. Both sets of assumptions are consistent with available data and reveal a structural uncertainty that was not apparent in either model in isolation. Those relying on projections from models should consider outputs from both models and this analysis provides further evidence of the benefits of systematic model comparison for enhancing modelling analyses.

Journal article

Perez Guzman PN, Daunt A, Mukherjee S, Crook P, Forlano R, Kont M, Lochen A, Vollmer M, Middleton P, Judge R, Harlow C, Soubieres A, Cooke G, White PJ, Hallett T, Aylin P, Ferguson N, Hauck K, Thursz M, Nayagam Set al., 2020, Clinical characteristics and predictors of outcomes of hospitalized patients with COVID-19 in a multi-ethnic London NHS Trust: a retrospective cohort study, Clinical Infectious Diseases, Vol: 2020, Pages: 1-11, ISSN: 1058-4838

Background: Emerging evidence suggests ethnic minorities are disproportionatelyaffected by COVID-19. Detailed clinical analyses of multi-cultural hospitalized patientcohorts remain largely undescribed.Methods: We performed regression, survival andcumulative competing risk analyses to evaluate factors associated with mortality inpatients admitted for COVID-19 in three large London hospitals between February 25and April 5, censored as of May 1, 2020.Results: Of 614 patients (median age 69years, (IQR 25) and 62% male), 381 (62%) had been discharged alive, 178 (29%)died and 55 (9%) remained hospitalized at censoring. Severe hypoxemia (aOR 4.25,95%CI 2.36-7.64), leukocytosis (aOR 2.35, 95%CI 1.35-4.11), thrombocytopenia (aOR1.01, 95%CI 1.00-1.01, increase per 10x9decrease), severe renal impairment (aOR5.14, 95%CI 2.65-9.97), and low albumin (aOR 1.06, 95%CI 1.02-1.09, increase per gdecrease) were associated with death. Forty percent (244) were from black, Asian andother minority ethnic (BAME) groups, 38% (235) white and for 22% (135) ethnicity wasunknown. BAME patients were younger and had fewer comorbidities. Whilst theunadjusted odds of death did not differ by ethnicity, when adjusting for age, sex andcomorbidities, black patients were at higher odds of death compared to whites (aOR1.69, 95%CI 1.00-2.86). This association was stronger when further adjusting foradmission severity (aOR 1.85 95% CI 1.06-3.24). Conclusions: BAME patients were over-represented in our cohort and, whenaccounting for demographic and clinical profile of admission, black patients were atincreased odds of death. Further research is needed into biologic drivers of differencesin COVID-19 outcomes by ethnicity.

Journal article

Mohamed Z, Scott N, Al-Kurdi D, Selvapatt N, Thursz MR, Lemoine M, Brown AS, Nayagam Set al., 2020, Cost-effectiveness of strategies to improve HCV screening, linkage-to-care and treatment in remand prison settings in England., Liver International, Vol: 40, Pages: 2950-2960, ISSN: 1478-3223

BACKGROUND: A simplified cascade-of-care may improve screening and treatment uptake among incarcerated individuals. We assessed the cost-effectiveness of traditional and simplified screening and treatment in a London remand prison. METHODS: Using empirical data from Her Majesty's Prison (HMP) Wormwood Scrubs, London, we designed a decision tree and Markov transition state model using national average data for HCV screening and treatment for the base-case scenario. This was compared two alternative strategies; (1) general prison population screening and treatment and (2) prioritising screening and treatment among people who inject drugs (PWID) combined with general prison population screening and treatment. Strategies varied the rates of screening (47-90%), linkage-to-care (60-86%) and treatment (21-85%). Cost, utility and disease transition rates were obtained from existing literature. Outcome measures were; screening, treatment and disease-related costs per admitted individual, quality-adjusted life years (QALYs). Incremental cost-effectiveness ratios (ICERs) were calculated for each intervention. All costs and utilities were discounted at a rate of 3.5% per annum. Both univariate and probabilistic sensitivity analyses have been conducted. RESULTS: In our cohort of 5,239 incarcerated individuals with an estimated chronic HCV prevalence of 2.6%, all strategy ICER values (£3,565-10,300) fell below the national willingness to pay threshold (£30,000). Increased successful treatment (7-54%) was observed by an optimising cascade-of-care. A robust sensitivity analysis identified treatment cost of, QALY for mild liver disease and probability of completing treatment as important factors that impact the ICER value. CONCLUSION: In our remand setting, optimising adherence to the cascade-of-care is cost-effective. Where universal screening is not practical, a stratified approach focused on intensive screening and treatment of PWID also results in increased treatment

Journal article

Nathwani R, Mukherjee S, Forlano R, Mullish BH, Vergis N, Selvapatt N, Manousou P, Nayagam S, Lemoine M, Dhar Aet al., 2020, Letter: liver disease and COVID-19 - not the perfect storm, Alimentary Pharmacology and Therapeutics, Vol: 52, Pages: 572-574, ISSN: 0269-2813

This article is linked to Garrido et al papers. To view these articles, visit https://doi.org/10.1111/apt.15813 and https://doi.org/10.1111/apt.15886.

Journal article

Vollmer M, Radhakrishnan S, Kont M, Flaxman S, Bhatt S, Costelloe C, Honeyford C, Aylin P, Cooke G, Redhead J, White P, Ferguson N, Hauck K, Nayagam AS, Perez Guzman PNet al., 2020, Report 29: The impact of the COVID-19 epidemic on all-cause attendances to emergency departments in two large London hospitals: an observational study

The health care system in England has been highly affected by the surge in demand due to patients afflicted by COVID-19. Yet the impact of the pandemic on the care seeking behaviour of patients and thus on Emergency department (ED) services is unknown, especially for non-COVID-19 related emergencies. In this report, we aimed to assess how the reorganisation of hospital care and admission policies to respond to the COVID-19 epidemic affected ED attendances and emergency hospital admissions. We performed time-series analyses of present year vs historic (2015-2019) trends of ED attendances between March 12 and May 31 at two large central London hospitals part of Imperial College Healthcare NHS Trust (ICHNT) and compared these to regional and national trends. Historic attendances data to ICHNT and publicly available NHS situation reports were used to calibrate time series auto-regressive integrated moving average (ARIMA) forecasting models. We thus predicted the (conterfactual) expected number of ED attendances between March 12 (when the first public health measure leading to lock-down started in England) to May 31, 2020 (when the analysis was censored) at ICHNT, at all acute London Trusts and nationally. The forecasted trends were compared to observed data for the same periods of time. Lastly, we analysed the trends at ICHNT disaggregating by mode of arrival, distance from postcode of patient residence to hospital and primary diagnosis amongst those that were subsequently admitted to hospital and compared these data to an average for the same period of time in the years 2015 to 2019.During the study period (January 1 to May 31, 2020) there was an overall decrease in ED attendances of 35% at ICHNT, of 50% across all London NHS Trusts and 53% nationally. For ICHNT, the decrease in attendances was mainly amongst those aged younger than 65 and those arriving by their own means (e.g. personal or public transport). Increasing distance (km) from postcode of residence to hospi

Report

McCabe R, Schmit N, Christen P, D'Aeth J, Lochen A, Rizmie D, Nayagam AS, Miraldo M, Aylin P, Bottle R, Perez Guzman PN, Ghani A, Ferguson N, White PJ, Hauck Ket al., 2020, Report 27 Adapting hospital capacity to meet changing demands during the COVID-19 pandemic

To meet the growing demand for hospital care due to the COVID-19 pandemic, England implemented a range of hospital provision interventions including the procurement of equipment, the establishment of additional hospital facilities and the redeployment of staff and other resources. Additionally, to further release capacity across England’s National Health Service (NHS), elective surgery was cancelled in March 2020, leading to a backlog of patients requiring care. This created a pressure on the NHS to reintroduce elective procedures, which urgently needs to be addressed. Population-level measures implemented in March and April 2020 reduced transmission of SARS-CoV-2, prompting a gradual decline in the demand for hospital care by COVID-19 patients after the peak in mid-April. Planning capacity to bring back routine procedures for non-COVID-19 patients whilst maintaining the ability to respond to any potential future increases in demand for COVID-19 care is the challenge currently faced by healthcare planners.In this report, we aim to calculate hospital capacity for emergency treatment of COVID-19 and other patients during the pandemic surge in April and May 2020; to evaluate the increase in capacity achieved via five interventions (cancellation of elective surgery, field hospitals, use of private hospitals, and deployment of former and newly qualified medical staff); and to determine how to re-introduce elective surgery considering continued demand from COVID-19 patients. We do this by modelling the supply of acute NHS hospital care, considering different capacity scenarios, namely capacity before the pandemic (baseline scenario) and after the implementation of capacity expansion interventions that impact available general and acute (G&A) and critical care (CC) beds, staff and ventilators. Demand for hospital care is accounted for in terms of non-COVID-19 and COVID-19 patients. Our results suggest that NHS England would not have had sufficient daily capacity

Report

Walker PGT, Whittaker C, Watson OJ, Baguelin M, Winskill P, Hamlet A, Djafaara BA, Cucunubá Z, Olivera Mesa D, Green W, Thompson H, Nayagam S, Ainslie KEC, Bhatia S, Bhatt S, Boonyasiri A, Boyd O, Brazeau NF, Cattarino L, Cuomo-Dannenburg G, Dighe A, Donnelly CA, Dorigatti I, van Elsland SL, FitzJohn R, Fu H, Gaythorpe KAM, Geidelberg L, Grassly N, Haw D, Hayes S, Hinsley W, Imai N, Jorgensen D, Knock E, Laydon D, Mishra S, Nedjati-Gilani G, Okell LC, Unwin HJ, Verity R, Vollmer M, Walters CE, Wang H, Wang Y, Xi X, Lalloo DG, Ferguson NM, Ghani ACet al., 2020, The impact of COVID-19 and strategies for mitigation and suppression in low- and middle-income countries, Science, Vol: 369, Pages: 413-422, ISSN: 0036-8075

The ongoing COVID-19 pandemic poses a severe threat to public health worldwide. We combine data on demography, contact patterns, disease severity, and health care capacity and quality to understand its impact and inform strategies for its control. Younger populations in lower income countries may reduce overall risk but limited health system capacity coupled with closer inter-generational contact largely negates this benefit. Mitigation strategies that slow but do not interrupt transmission will still lead to COVID-19 epidemics rapidly overwhelming health systems, with substantial excess deaths in lower income countries due to the poorer health care available. Of countries that have undertaken suppression to date, lower income countries have acted earlier. However, this will need to be maintained or triggered more frequently in these settings to keep below available health capacity, with associated detrimental consequences for the wider health, well-being and economies of these countries.

Journal article

Perez Guzman PN, Daunt A, Mukherjee S, Crook P, Forlano R, Kont M, Lochen A, Vollmer M, Middleton P, Judge R, Harlow C, Soubieres A, Cooke G, White P, Hallett T, Aylin P, Ferguson N, Hauck K, Thursz M, Nayagam ASet al., 2020, Report 17: Clinical characteristics and predictors of outcomes of hospitalised patients with COVID-19 in a London NHS Trust: a retrospective cohort study

Clinical characteristics and determinants of outcomes for hospitalised COVID-19 patients in the UK remain largely undescribed and emerging evidence suggests ethnic minorities might be disproportionately affected. We describe the characteristics and outcomes of patients hospitalised for COVID-19 in three large London hospitals with a multi-ethnic catchment population.We performed a retrospective cohort study on all patients hospitalised with laboratory-confirmed SARS-CoV-2 infection at Imperial College Healthcare NHS Trust between February 25 and April 5, 2020. Outcomes were recorded as of April 19, 2020. Logistic regression models, survival analyses and cumulative competing risk analyses were performed to evaluate factors associated with COVID-19 hospital mortality.Of 520 patients in this cohort (median age 67 years, (IQR 26) and 62% male), 302 (68%) had been discharged alive, 144 (32%) died and 74 (14%) were still hospitalised at the time of censoring. Increasing age (adjusted odds ratio [aOR] 2·16, 95%CI 1·50-3·12), severe hypoxia (aOR 3·75, 95%CI 1·80-7·80), low platelets (aOR 0·65, 95%CI 0.49·0·85), reduced estimated glomerular filtration rate (aOR 4·11, 95%CI 1·58-10·69), bilirubin >21mmol/L (aOR 2·32, 95%CI 1·05-5·14) and low albumin (aOR 0·77, 9%%CI 0·59-1·01) were associated with increased risk of in-hospital mortality. Individual comorbidities were not independently associated with risk of death. Regarding ethnicity, 209 (40%) were from a black and Asian minority, for 115 (22%) ethnicity was unknown and 196 (38%) patients were white. Compared to the latter, black patients were significantly younger and had less comorbidities. Whilst the crude OR of death of black compared to white patients was not significant (1·14, 95%CI 0·69-1·88, p=0.62), adjusting for age and comorbidity showed a trend towards significance

Report

Christen P, D'Aeth J, Lochen A, McCabe R, Rizmie D, Schmit N, Nayagam AS, Miraldo M, White P, Aylin P, Bottle R, Perez Guzman PN, Donnelly C, Ghani A, Ferguson N, Hauck Ket al., 2020, Report 15: Strengthening hospital capacity for the COVID-19 pandemic

Planning for extreme surges in demand for hospital care of patients requiring urgent life-saving treatment for COVID-19, and other conditions, is one of the most challenging tasks facing healthcare commissioners and care providers during the pandemic. Due to uncertainty in expected patient numbers requiring care, as well as evolving needs day by day, planning hospital capacity is challenging. Health systems that are well prepared for the pandemic can better cope with large and sudden changes in demand by implementing strategies to ensure adequate access to care. Thereby the burden of the pandemic can be mitigated, and many lives saved. This report presents the J-IDEA pandemic planner, a hospital planning tool to calculate how much capacity in terms of beds, staff and ventilators is obtained by implementing healthcare provision interventions affecting the management of patient care in hospitals. We show how to assess baseline capacity, and then calculate how much capacity is gained by various healthcare interventions using impact estimates that are generated as part of this study. Interventions are informed by a rapid review of policy decisions implemented or being considered in 12 European countries over the past few months , an evaluation of the impact of the interventions on capacity using a variety of research methods, and by a review of key parameters in the care of COVID-19 patients.The J-IDEA planner is publicly available, interactive and adaptable to different and changing circumstances and newly emerging evidence. The planner estimates the additional number of beds, medical staff and crucial medical equipment obtained under various healthcare interventions using flexible inputs on assumptions of existing capacities, the number of hospitalisations, beds-to-staff ratios, and staff absences due to COVID-19. A detailed user guide accompanies the planner. The planner was developed rapidly and has limitations which we will address in future iterations. It support

Report

Shimakawa Y, Ndow G, Njie R, Njai HF, Takahashi K, Akbar SMF, Cohen D, Nayagam S, Jeng A, Ceesay A, Sanneh B, Baldeh I, Imaizumi M, Moriyama K, Aoyagi K, D'Alessandro U, Mishiro S, Chemin I, Mendy M, Thursz MR, Lemoine Met al., 2020, Hepatitis B core-related antigen (HBcrAg): an alternative to HBV DNA to assess treatment eligibility in Africa, Clinical Infectious Diseases, Vol: 70, Pages: 1442-1452, ISSN: 1058-4838

BACKGROUND: To eliminate hepatitis B virus (HBV) infection, it is essential to scale up testing and treatment. However, conventional tools to assess treatment eligibility, particularly nucleic acid testing (NAT) to quantify HBV DNA, are hardly available and affordable in resource-limited countries. We therefore assessed the performance of novel immunoassay, hepatitis B core-related antigen (HBcrAg), as an inexpensive (US$ <10-15/assay) alternative to NAT to diagnose clinically important HBV DNA thresholds (≥2,000; ≥20,000; and ≥200,000 IU/ml), and select patients for antiviral therapy in Africa. METHODS: Using well-characterized cohort of treatment-naïve patients with chronic HBV infection in The Gambia, we evaluated the accuracy of serum HBcrAg to diagnose HBV DNA levels, and to indicate treatment eligibility determined by the American Association for the Study of Liver Diseases, based on the reference tests (HBV DNA, HBV e antigen (HBeAg), alanine transaminase (ALT), liver histopathology and/or FibroScan). RESULTS: A total of 284 treatment-naïve patients were included in the analysis. The area under the receiver operating characteristic curve (AUROC), sensitivity and specificity of serum HBcrAg were: 0.88 (95% CI: 0.82-0.93), 83.3% and 83.9% to diagnose HBV DNA ≥2,000 IU/ml; and 0.94 (0.88-0.99), 91.4% and 93.2% for ≥200,000 IU/ml. A simplified treatment algorithm using HBcrAg without HBV DNA showed high AUROC (0.91 (95% CI: 0.88-0.95)) with a sensitivity of 96.6% and specificity of 85.8%. CONCLUSIONS: HBcrAg might be an accurate alternative to HBV DNA quantification as a simple and inexpensive tool to identify HBV-infected patients in need of antiviral therapy in low- and middle-income countries.

Journal article

Nayagam S, Shimakawa Y, Lemoine M, 2020, Mother-to-child transmission of hepatitis B: What more needs to be done to eliminate it around the world?, Journal of Viral Hepatitis, Vol: 27, Pages: 342-349, ISSN: 1345-2533

Mother‐to‐child transmission (MTCT) of hepatitis B virus (HBV) is a key component of the hepatitis B burden worldwide. Despite its efficacy to prevent HBV transmission, infant vaccination is not enough to control HBV MTCT. Additional efforts are urgently needed to evaluate and scale‐up preventive strategies especially in endemic countries, which are most affected. This review highlights the efficacy and barriers of the currently validated measures for the prevention of HBV MTCT and proposes alternatives adapted to resource‐limited settings to eventually achieve HBV elimination worldwide.

Journal article

Nayagam S, Thursz M, 2019, Strategies for Global Elimination of Chronic HBV Infection: 2019 Update, Current Hepatology Reports, Vol: 18, Pages: 300-309

Journal article

Li X, Mukandavire C, Cucunubá Z, Abbas K, Clapham H, Jit M, Johnson H, Papadopoulos T, Vynnycky E, Brisson M, Carter E, Clark A, de Villiers M, Eilertson K, Ferrari M, Gamkrelidze I, Gaythorpe K, Grassly N, Hallett T, Jackson M, Jean K, Karachaliou A, Klepac P, Lessler J, Li X, Moore S, Nayagam S, Nguyen DM, Razavi H, Razavi-Shearer D, Resch S, Sanderson C, Sweet S, Sy S, Tam Y, Tanvir H, Tran QM, Trotter C, Truelove S, van Zandvoort K, Verguet S, Walker N, Winter A, Ferguson N, Garske T, Vaccine Impact Modelling Consortiumet al., 2019, Estimating the health impact of vaccination against 10 pathogens in 98 low and middle income countries from 2000 to 2030, Publisher: medRxiv

Background The last two decades have seen substantial expansion of childhood vaccination programmes in low and middle income countries (LMICs). Here we quantify the health impact of these programmes by estimating the deaths and disability-adjusted life years (DALYs) averted by vaccination with ten antigens in 98 LMICs between 2000 and 2030. Methods Independent research groups provided model-based disease burden estimates under a range of vaccination coverage scenarios for ten pathogens: hepatitis B (HepB), Haemophilus influenzae type b (Hib), human papillomavirus (HPV), Japanese encephalitis (JE), measles, Neisseria meningitidis serogroup A (MenA), Streptococcus pneumoniae, rotavirus, rubella, yellow fever. Using standardized demographic data and vaccine coverage estimates for routine and supplementary immunization activities, the impact of vaccination programmes on deaths and DALYs was determined by comparing model estimates from the no vaccination counterfactual scenario with those from a default coverage scenario. We present results in two forms: deaths/DALYs averted in a particular calendar year, and in a particular annual birth cohort. Findings We estimate that vaccination will have averted 70 (2.5-97.5% quantile range 54-80) million deaths between 2000 and 2030 across the 98 countries and ten pathogens considered, 35 (30-40) million of these between 2000-2018. From 2000-2018, this represents a 41% (36-44%) reduction in deaths due to the ten pathogens relative to the no vaccination counterfactual. Most (95% (93-99%)) of this impact is in under-five age mortality, notably from measles. Over the lifetime of birth cohorts born between 2000 and 2030, we predict that 121 (102-136) million deaths will be averted by vaccination, of which 58 (31-82) and 38 (10-81) million are due to measles and Hepatitis B vaccination, respectively. We estimate that recent increases in vaccine coverage and introductions of additional vaccines will result in a 72% (64-75%) reductio

Working paper

Heffernan A, Cooke G, Nayagam S, Hallett TB, Thursz Met al., 2019, Scaling up prevention and treatment towards the elimination of hepatitis C: a global mathematical model, Lancet, Vol: 393, Pages: 1319-1329, ISSN: 0140-6736

BackgroundThe revolution in hepatitis C virus (HCV) treatment through the development of direct-acting antivirals (DAAs) has generated international interest in the global elimination of the disease as a public health threat. In 2017, this led WHO to establish elimination targets for 2030. We evaluated the impact of public health interventions on the global HCV epidemic and investigated whether WHO's elimination targets could be met.MethodsWe developed a dynamic transmission model of the global HCV epidemic, calibrated to 190 countries, which incorporates data on demography, people who inject drugs (PWID), current coverage of treatment and prevention programmes, natural history of the disease, HCV prevalence, and HCV-attributable mortality. We estimated the worldwide impact of scaling up interventions that reduce risk of transmission, improve access to treatment, and increase screening for HCV infection by considering six scenarios: no change made to existing levels of diagnosis or treatment; sequentially adding the following interventions: blood safety and infection control, PWID harm reduction, offering of DAAs at diagnosis, and outreach screening to increase the number diagnosed; and a scenario in which DAAs are not introduced (ie, treatment is only with pegylated interferon and oral ribavirin) to investigate the effect of DAA use. We explored the effect of varying the coverage or impact of these interventions in sensitivity analyses and also assessed the impact on the global epidemic of removing certain key countries from the package of interventions.FindingsBy 2030, interventions that reduce risk of transmission in the non-PWID population by 80% and increase coverage of harm reduction services to 40% of PWID could avert 14·1 million (95% credible interval 13·0–15·2) new infections. Offering DAAs at time of diagnosis in all countries could prevent 640 000 deaths (620 000–670 000) from cirrhosis and liver cancer. A comprehensive p

Journal article

Cooke GS, Andrieux-Meyer I, Applegate TL, Atun R, Burry JR, Cheinquer H, Dusheiko G, Feld JJ, Gore C, Griswold MG, Hamid S, Hellard ME, Hou JL, Howell J, Jia J, Kravchenko N, Lazarus JV, Lemoine M, Lesi OA, Maistat L, McMahon BJ, Razavi H, Roberts TR, Simmons B, Sonderup MW, Spearman CW, Taylor BE, Thomas DL, Waked I, Ward JW, Wiktor SZ, Abdo A, Aggarwal R, Aghemo A, Al-Judaibi B, Al Mahtab M, Altaf A, Ameen Z, Asselah T, Baatarkkhuu O, Barber E, Barnes E, Boulet P, Burrows L, Butsashvili M, Chan E, Chow C, Cowie B, Cunningham C, de Araujo A, Diap G, Dore G, Doyle J, Elsayed M, Fajardo E, Gane E, Getehun A, Goldberg D, Got T, Hickman M, Hill A, Hutchinson S, Jones C, Kamili S, Khan A, Lee A, Lee TY, Malani J, Morris TM, Nayagam S, Njouom R, Ocama P, Pedrana A, Peeling R, Reddy A, Roberts T, Sacks J, Sarin S, Shimakawa Y, Silva M, Skala P, Taylor-Robinson S, Thompson A, Thursz M, Tonganibeia A, Wallace J, Ward J, Wolff F, Vickerman P, Yau Jet al., 2019, Accelerating the elimination of viral hepatitis: a Lancet Gastroenterology & Hepatology Commission, The Lancet Gastroenterology and Hepatology, Vol: 4, Pages: 135-184, ISSN: 2468-1253

Viral hepatitis is a major public health threat and a leading cause of death worldwide. Annual mortality from viral hepatitis is similar to that of other major infectious diseases such as HIV and tuberculosis. Highly effective prevention measures and treatments have made the global elimination of viral hepatitis a realistic goal, endorsed by all WHO member states. Ambitious targets call for a global reduction in hepatitis-related mortality of 65% and a 90% reduction in new infections by 2030. This Commission draws together a wide range of expertise to appraise the current global situation and to identify priorities globally, regionally, and nationally needed to accelerate progress. We identify 20 heavily burdened countries that account for over 75% of the global burden of viral hepatitis. Key recommendations include a greater focus on national progress towards elimination with support given, if necessary, through innovative financing measures to ensure elimination programmes are fully funded by 2020. In addition to further measures to improve access to vaccination and treatment, greater attention needs to be paid to access to affordable, high-quality diagnostics if testing is to reach the levels needed to achieve elimination goals. Simplified, decentralised models of care removing requirements for specialised prescribing will be required to reach those in need, together with sustained efforts to tackle stigma and discrimination. We identify key examples of the progress that has already been made in many countries throughout the world, demonstrating that sustained and coordinated efforts can be successful in achieving the WHO elimination goals.

Journal article

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