Imperial College London

Professor Christl Donnelly CBE FMedSci FRS

Faculty of MedicineSchool of Public Health

Visiting Professor
 
 
 
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Contact

 

c.donnelly Website

 
 
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School of Public HealthWhite City Campus

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Summary

 

Publications

Publication Type
Year
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530 results found

McCabe R, Danelian G, Panovska-Griffiths J, Donnelly CAet al., 2024, Inferring community transmission of SARS-CoV-2 in the United Kingdom using the ONS COVID-19 Infection Survey., Infect Dis Model, Vol: 9, Pages: 299-313

Key epidemiological parameters, including the effective reproduction number, R(t), and the instantaneous growth rate, r(t), generated from an ensemble of models, have been informing public health policy throughout the COVID-19 pandemic in the four nations of the United Kingdom of Great Britain and Northern Ireland (UK). However, estimation of these quantities became challenging with the scaling down of surveillance systems as part of the transition from the "emergency" to "endemic" phase of the pandemic. The Office for National Statistics (ONS) COVID-19 Infection Survey (CIS) provided an opportunity to continue estimating these parameters in the absence of other data streams. We used a penalised spline model fitted to the publicly-available ONS CIS test positivity estimates to produce a smoothed estimate of the prevalence of SARS-CoV-2 positivity over time. The resulting fitted curve was used to estimate the "ONS-based" R(t) and r(t) across the four nations of the UK. Estimates produced under this model are compared to government-published estimates with particular consideration given to the contribution that this single data stream can offer in the estimation of these parameters. Depending on the nation and parameter, we found that up to 77% of the variance in the government-published estimates can be explained by the ONS-based estimates, demonstrating the value of this singular data stream to track the epidemic in each of the four nations. We additionally find that the ONS-based estimates uncover epidemic trends earlier than the corresponding government-published estimates. Our work shows that the ONS CIS can be used to generate key COVID-19 epidemiological parameters across the four UK nations, further underlining the enormous value of such population-level studies of infection. This is not intended as an alternative to ensemble modelling, rather it is intended as a potential solution to the aforementioned challenge faced by public h

Journal article

Hampshire A, Azor A, Atchison C, Trender W, Hellyer PJ, Giunchiglia V, Husain M, Cooke GS, Cooper E, Lound A, Donnelly CA, Chadeau-Hyam M, Ward H, Elliott Pet al., 2024, Cognition and memory after Covid-19 in a large community sample, New England Journal of Medicine, Vol: 390, Pages: 806-818, ISSN: 0028-4793

BACKGROUND: Cognitive symptoms after coronavirus disease 2019 (Covid-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are well-recognized. Whether objectively measurable cognitive deficits exist and how long they persist are unclear. METHODS: We invited 800,000 adults in a study in England to complete an online assessment of cognitive function. We estimated a global cognitive score across eight tasks. We hypothesized that participants with persistent symptoms (lasting ≥12 weeks) after infection onset would have objectively measurable global cognitive deficits and that impairments in executive functioning and memory would be observed in such participants, especially in those who reported recent poor memory or difficulty thinking or concentrating ("brain fog"). RESULTS: Of the 141,583 participants who started the online cognitive assessment, 112,964 completed it. In a multiple regression analysis, participants who had recovered from Covid-19 in whom symptoms had resolved in less than 4 weeks or at least 12 weeks had similar small deficits in global cognition as compared with those in the no-Covid-19 group, who had not been infected with SARS-CoV-2 or had unconfirmed infection (-0.23 SD [95% confidence interval {CI}, -0.33 to -0.13] and -0.24 SD [95% CI, -0.36 to -0.12], respectively); larger deficits as compared with the no-Covid-19 group were seen in participants with unresolved persistent symptoms (-0.42 SD; 95% CI, -0.53 to -0.31). Larger deficits were seen in participants who had SARS-CoV-2 infection during periods in which the original virus or the B.1.1.7 variant was predominant than in those infected with later variants (e.g., -0.17 SD for the B.1.1.7 variant vs. the B.1.1.529 variant; 95% CI, -0.20 to -0.13) and in participants who had been hospitalized than in those who had not been hospitalized (e.g., intensive care unit admission, -0.35 SD; 95% CI, -0.49 to -0.20). Results of the analyses were similar to

Journal article

Rivera LF, Lezcano-Coba C, Galué J, Rodriguez X, Juarez Y, de Souza WM, Capitan-Barrios Z, Valderrama A, Abrego L, Cedeño H, Jackman C, Waggoner JJ, Aguilar PV, Guzman H, Weaver SC, Tesh RB, López-Vèrges S, Donnelly CA, Estofolete CF, Nogueira ML, Faria NR, Vasilakis N, Vittor AY, Smith DR, Carrera J-Pet al., 2024, Clinical and epidemiological characteristics of Madariaga and Venezuelan equine encephalitis virus infections., medRxiv

Madariaga virus (MADV) and Venezuelan equine encephalitis virus (VEEV) are emerging arboviruses affecting rural and remote areas of Latin America. However, there are limited clinical and epidemiological reports available, and outbreaks are occurring at an increasing frequency. We addressed this gap by analyzing all the available clinical and epidemiological data of MADV and VEEV infections recorded since 1961 in Panama. A total of 168 of human alphavirus encephalitis cases were detected in Panama from 1961 to 2023. Here we describe the clinical signs and symptoms and epidemiological characteristics of these cases, and also explored signs and symptoms as potential predictors of encephalitic alphavirus infection when compared to those of other arbovirus infections occurring in the region. Our results highlight the challenges clinical diagnosis of alphavirus disease in endemic regions with overlapping circulation of multiple arboviruses.

Journal article

Penn MJ, Miles V, Astley KL, Ham C, Woodroffe R, Rowcliffe M, Donnelly CAet al., 2024, Sherlock—A flexible, low-resource tool for processing camera-trapping images, Methods in Ecology and Evolution, Vol: 15, Pages: 91-102

The use of camera traps to study wildlife has increased markedly in the last two decades. Camera surveys typically produce large data sets which require processing to isolate images containing the species of interest. This is time consuming and costly, particularly if there are many empty images that can result from false triggers. Computer vision technology can assist with data processing, but existing artificial intelligence algorithms are limited by the requirement of a training data set, which itself can be challenging to acquire. Furthermore, deep-learning methods often require powerful hardware and proficient coding skills. We present Sherlock, a novel algorithm that can reduce the time required to process camera trap data by removing a large number of unwanted images. The code is adaptable, simple to use and requires minimal processing power. We tested Sherlock on 240,596 camera trap images collected from 46 cameras placed in a range of habitats on farms in Cornwall, United Kingdom, and set the parameters to find European badgers (Meles meles). The algorithm correctly classified 91.9% of badger images and removed 49.3% of the unwanted ‘empty’ images. When testing model parameters, we found that faster processing times were achieved by reducing both the number of sampled pixels and ‘bouncing’ attempts (the number of paths explored to identify a disturbance), with minimal implications for model sensitivity and specificity. When Sherlock was tested on two sites which contained no livestock in their images, its performance greatly improved and it removed 92.3% of the empty images. Although further refinements may improve its performance, Sherlock is currently an accessible, simple and useful tool for processing camera trap data.

Journal article

Penn MJ, Scheidwasser N, Penn J, Donnelly CA, Duchêne DA, Bhatt Set al., 2023, Leaping through Tree Space: Continuous Phylogenetic Inference for Rooted and Unrooted Trees., Genome Biol Evol, Vol: 15

Phylogenetics is now fundamental in life sciences, providing insights into the earliest branches of life and the origins and spread of epidemics. However, finding suitable phylogenies from the vast space of possible trees remains challenging. To address this problem, for the first time, we perform both tree exploration and inference in a continuous space where the computation of gradients is possible. This continuous relaxation allows for major leaps across tree space in both rooted and unrooted trees, and is less susceptible to convergence to local minima. Our approach outperforms the current best methods for inference on unrooted trees and, in simulation, accurately infers the tree and root in ultrametric cases. The approach is effective in cases of empirical data with negligible amounts of data, which we demonstrate on the phylogeny of jawed vertebrates. Indeed, only a few genes with an ultrametric signal were generally sufficient for resolving the major lineages of vertebrates. Optimization is possible via automatic differentiation and our method presents an effective way forward for exploring the most difficult, data-deficient phylogenetic questions.

Journal article

McCabe R, Donnelly CA, 2023, Public awareness of and opinions on the use of mathematical transmission modelling to inform public health policy in the United Kingdom., J R Soc Interface, Vol: 20

Mathematical modelling is used to inform public health policy, particularly so during the COVID-19 pandemic. As the public are key stakeholders, understanding the public perceptions of these tools is vital. To complement our previous study on the science-policy interface, novel survey data were collected via an online panel ('representative' sample) and social media ('non-probability' sample). Many questions were asked twice, in reference to the period 'prior to' (retrospectively) and 'during' the COVID-19 pandemic. Respondents reported being increasingly aware of modelling in informing policy during the pandemic, with higher levels of awareness among social media respondents. Modelling informing policy was perceived as more reliable during the pandemic than in reference to the pre-pandemic period in both samples. Trust in government public health advice remained high within both samples but was lower during the pandemic in comparison with the (retrospective) pre-pandemic period. The decay in trust was greater among social media respondents. Many respondents explicitly made the distinction that their trust was reserved for 'scientists' and not 'politicians'. Almost all respondents believed governments have responsibility for communicating modelling to the public. These results provide a reminder of the skewed conclusions that could be drawn from non-representative samples.

Journal article

Carrera J-P, Araúz D, Rojas A, Cardozo F, Stittleburg V, Morales Claro I, Galue J, Lezcano-Coba C, Romero Rebello Moreira F, -Rivera LF, Chen-Germán M, Moreno B, Capitan-Barrios Z, López-Vergès S, Pascale JM, Sabino EC, Valderrama A, Hanley KA, Donnelly CA, Vasilakis N, Faria NR, Waggoner JJet al., 2023, Real-time RT-PCR for Venezuelan equine encephalitis complex, Madariaga and Eastern equine encephalitis viruses: application in human and mosquito public health surveillance in Panama, Journal of Clinical Microbiology, Vol: 61, ISSN: 0095-1137

Eastern equine encephalitis virus (EEEV), Madariaga virus (MADV), and Venezuelan equine encephalitis virus complex (VEEV) are New World alphaviruses transmitted by mosquitoes. They cause febrile and sometimes severe neurological disease in human and equine hosts.Detecting them during the acute phase is hindered by nonspecific symptoms and limiteddiagnostic tools. We designed and clinically assessed reverse transcription polymerase chain reaction assays (rRT-PCRs) for VEEV complex, MADV, and EEEV using whole-genome sequences. Validation involved 15 retrospective serum samples from 2015-2017 outbreaks, 150 mosquito pools from 2015, and 118 prospective samples from 2021-2022 surveillance in Panama. The rRT-PCRs detected VEEV complex RNA in 10 samples (66.7%) from outbreaks, with one having both VEEV complex and MADV RNAs. VEEV complex RNA was found in 5 suspected dengue cases from disease surveillance. The rRT-PCR assays identified VEEV complex RNA in 3 Culex (Melanoconion) vomerifer pools, leading to VEEV isolates in 2. Phylogenetic analysis revealed the VEEV ID subtype in positive samples. Notably, 11.9% of dengue-like disease patients showed VEEV infections. Together, our rRT-PCR validation in human and mosquito samples suggests this method can be incorporated into mosquito and human encephalitic alphavirus surveillance programs in endemic regions.

Journal article

Gonçalves BP, Jassat W, Baruch J, Hashmi M, Rojek A, Dasgupta A, Martin-Loeches I, Reyes LF, Piubelli C, Citarella BW, Kartsonaki C, Lefèvre B, López Revilla JW, Lunn M, Harrison EM, Kraemer MUG, Shrapnel S, Horby P, Bisoffi Z, Olliaro PL, Merson L, ISARIC Clinical Characterisation Groupet al., 2023, A multi-country analysis of COVID-19 hospitalizations by vaccination status., Med, Vol: 4, Pages: 797-812.e2

BACKGROUND: Individuals vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when infected, can still develop disease that requires hospitalization. It remains unclear whether these patients differ from hospitalized unvaccinated patients with regard to presentation, coexisting comorbidities, and outcomes. METHODS: Here, we use data from an international consortium to study this question and assess whether differences between these groups are context specific. Data from 83,163 hospitalized COVID-19 patients (34,843 vaccinated, 48,320 unvaccinated) from 38 countries were analyzed. FINDINGS: While typical symptoms were more often reported in unvaccinated patients, comorbidities, including some associated with worse prognosis in previous studies, were more common in vaccinated patients. Considerable between-country variation in both in-hospital fatality risk and vaccinated-versus-unvaccinated difference in this outcome was observed. CONCLUSIONS: These findings will inform allocation of healthcare resources in future surges as well as design of longer-term international studies to characterize changes in clinical profile of hospitalized COVID-19 patients related to vaccination history. FUNDING: This work was made possible by the UK Foreign, Commonwealth and Development Office and Wellcome (215091/Z/18/Z, 222410/Z/21/Z, 225288/Z/22/Z, and 220757/Z/20/Z); the Bill & Melinda Gates Foundation (OPP1209135); and the philanthropic support of the donors to the University of Oxford's COVID-19 Research Response Fund (0009109). Additional funders are listed in the "acknowledgments" section.

Journal article

Vicco A, McCormack CP, Pedrique B, Amuasi JH, Awuah AA-A, Obirikorang C, Struck NS, Lorenz E, May J, Ribeiro I, Malavige GN, Donnelly CA, Dorigatti Iet al., 2023, A simulation-based method to inform serosurvey design for estimating the force of infection using existing blood samples., PLoS Comput Biol, Vol: 19

The extent to which dengue virus has been circulating globally and especially in Africa is largely unknown. Testing available blood samples from previous cross-sectional serological surveys offers a convenient strategy to investigate past dengue infections, as such serosurveys provide the ideal data to reconstruct the age-dependent immunity profile of the population and to estimate the average per-capita annual risk of infection: the force of infection (FOI), which is a fundamental measure of transmission intensity. In this study, we present a novel methodological approach to inform the size and age distribution of blood samples to test when samples are acquired from previous surveys. The method was used to inform SERODEN, a dengue seroprevalence survey which is currently being conducted in Ghana among other countries utilizing samples previously collected for a SARS-CoV-2 serosurvey. The method described in this paper can be employed to determine sample sizes and testing strategies for different diseases and transmission settings.

Journal article

Cooper BS, Evans S, Jafari Y, Pham TM, Mo Y, Lim C, Pritchard MG, Pople D, Hall V, Stimson J, Eyre DW, Read JM, Donnelly CA, Horby P, Watson C, Funk S, Robotham JV, Knight GMet al., 2023, The burden and dynamics of hospital-acquired SARS-CoV-2 in England., Nature, Vol: 623, Pages: 132-138

Hospital-based transmission had a dominant role in Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV) epidemics1,2, but large-scale studies of its role in the SARS-CoV-2 pandemic are lacking. Such transmission risks spreading the virus to the most vulnerable individuals and can have wider-scale impacts through hospital-community interactions. Using data from acute hospitals in England, we quantify within-hospital transmission, evaluate likely pathways of spread and factors associated with heightened transmission risk, and explore the wider dynamical consequences. We estimate that between June 2020 and March 2021 between 95,000 and 167,000 inpatients acquired SARS-CoV-2 in hospitals (1% to 2% of all hospital admissions in this period). Analysis of time series data provided evidence that patients who themselves acquired SARS-CoV-2 infection in hospital were the main sources of transmission to other patients. Increased transmission to inpatients was associated with hospitals having fewer single rooms and lower heated volume per bed. Moreover, we show that reducing hospital transmission could substantially enhance the efficiency of punctuated lockdown measures in suppressing community transmission. These findings reveal the previously unrecognized scale of hospital transmission, have direct implications for targeting of hospital control measures and highlight the need to design hospitals better equipped to limit the transmission of future high-consequence pathogens.

Journal article

Kim Y, Fournié G, Métras R, Song D, Donnelly CA, Pfeiffer DU, Nouvellet Pet al., 2023, Lessons for cross-species viral transmission surveillance from highly pathogenic avian influenza Korean cat shelter outbreaks., Nat Commun, Vol: 14

Recent highly pathogenic avian influenza A(H5N1) outbreaks in two Korean cat shelters highlight the need to enhance surveillance for cross-species viral transmission into animal populations kept by humans for non-agricultural or non-conventional livestock farming purposes from a One Health perspective.

Journal article

Atchison C, Davies B, Cooper E, Lound A, Whitaker M, Hampshire A, Azor A, Donnelly C, Chadeau M, Cooke G, Ward H, Elliott Pet al., 2023, Long-term impact of COVID-19 among 242,712 adults in England, Nature Communications, Vol: 14, ISSN: 2041-1723

The COVID-19 pandemic is having a lasting impact on health and well-being. We compare current self-reported health, quality of life and symptom profiles for people with ongoing symptoms following COVID-19 to those who have never tested positive for SARS-CoV-2 infection and those who have recovered from COVID-19. Overall, 276,840/800,000 (34·6%) of invited participants took part. Mental health and health-related quality of life were worse among participants with ongoing persistent symptoms post-COVID compared with those who had never had COVID-19 or had recovered. In this study, median duration of COVID-related symptoms (N = 130,251) was 1·3 weeks (inter-quartile range 6 days to 2 weeks), with 7·5% and 5·2% reporting ongoing symptoms ≥12 weeks and ≥52 weeks respectively. Female sex, ≥1 comorbidity and being infected when Wild-type variant was dominant were associated with higher probability of symptoms lasting ≥12 weeks and longer recovery time in those with persistent symptoms. Although COVID-19 is usually of short duration, some adults experience persistent and burdensome illness.

Journal article

Bhatia S, Parag KV, Wardle J, Nash RK, Imai N, Elsland SLV, Lassmann B, Brownstein JS, Desai A, Herringer M, Sewalk K, Loeb SC, Ramatowski J, Cuomo-Dannenburg G, Jauneikaite E, Unwin HJT, Riley S, Ferguson N, Donnelly CA, Cori A, Nouvellet Pet al., 2023, Retrospective evaluation of real-time estimates of global COVID-19 transmission trends and mortality forecasts, PLOS ONE, Vol: 18, ISSN: 1932-6203

Journal article

Murphy C, Lim WW, Mills C, Wong JY, Chen D, Xie Y, Li M, Gould S, Xin H, Cheung JK, Bhatt S, Cowling BJ, Donnelly CAet al., 2023, Effectiveness of social distancing measures and lockdowns for reducing transmission of COVID-19 in non-healthcare, community-based settings, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 381, ISSN: 1364-503X

Journal article

Ward H, Atchison C, Whitaker M, Davies B, Ashby D, Darzi A, Chadeau-Hyam M, Riley S, Donnelly CA, Barclay W, Cooke GS, Elliott Pet al., 2023, Design and implementation of a national program to monitor the prevalence of SARS-CoV-2 IgG antibodies in England using self-testing: the REACT-2 study, American Journal of Public Health, Pages: e1-e9, ISSN: 0090-0036

Data System. The UK Department of Health and Social Care funded the REal-time Assessment of Community Transmission-2 (REACT-2) study to estimate community prevalence of SARS-CoV-2 IgG (immunoglobulin G) antibodies in England. Data Collection/Processing. We obtained random cross-sectional samples of adults from the National Health Service (NHS) patient list (near-universal coverage). We sent participants a lateral flow immunoassay (LFIA) self-test, and they reported the result online. Overall, 905 991 tests were performed (28.9% response) over 6 rounds of data collection (June 2020-May 2021). Data Analysis/Dissemination. We produced weighted estimates of LFIA test positivity (validated against neutralizing antibodies), adjusted for test performance, at local, regional, and national levels and by age, sex, and ethnic group and area-level deprivation score. In each round, fieldwork occurred over 2 weeks, with results reported to policymakers the following week. We disseminated results as preprints and peer-reviewed journal publications. Public Health Implications. REACT-2 estimated the scale and variation in antibody prevalence over time. Community self-testing and -reporting produced rapid insights into the changing course of the pandemic and the impact of vaccine rollout, with implications for future surveillance. (Am J Public Health. Published online ahead of print September 21, 2023:e1-e9. https://doi.org/10.2105/AJPH.2023.307381).

Journal article

Yang J, Lo NC, Dankwa EA, Donnelly CA, Gupta R, Montgomery MP, Weng MK, Martin NKet al., 2023, Determining Herd Immunity Thresholds for Hepatitis A Virus Transmission to Inform Vaccination Strategies Among People Who Inject Drugs in 16 US States, CLINICAL INFECTIOUS DISEASES, ISSN: 1058-4838

Journal article

Shah N, Xue B, Xu Z, Yang H, Marwali E, Dalton H, Payne PPR, Lu CS, Said Aet al., 2023, Validation of extracorporeal membrane oxygenation mortality prediction and severity of illness scores in an international COVID-19 cohort, ARTIFICIAL ORGANS, Vol: 47, Pages: 1490-1502, ISSN: 0160-564X

Journal article

Whitaker M, Davies B, Atchison C, Barclay W, Ashby D, Darzi A, Riley S, Cooke G, Donnelly C, Chadeau M, Elliott P, Ward Het al., 2023, SARS-CoV-2 rapid antibody test results and subsequent risk of hospitalisation and death in 361,801 people, Nature Communications, Vol: 14, ISSN: 2041-1723

The value of SARS-CoV-2 lateral flow immunoassay (LFIA) tests for estimating individual disease risk is unclear. The REACT-2 study in England, UK, obtained self-administered SARS-CoV-2 LFIA test results from 361,801 adults in January-May 2021. Here, we link to routine data on subsequent hospitalisation (to September 2021), and death (to December 2021). Among those who had received one or more vaccines, a negative LFIA is associated with increased risk of hospitalisation with COVID-19 (HR: 2.73 [95% confidence interval: 1.15,6.48]), death (all-cause) (HR: 1.59, 95% CI:1.07, 2.37), and death with COVID-19 as underlying cause (20.6 [1.83,232]). For people designated at high risk from COVID-19, who had received one or more vaccines, there is an additional risk of all-cause mortality of 1.9 per 1000 for those testing antibody negative compared to positive. However, the LFIA does not provide substantial predictive information over and above that which is available from detailed sociodemographic and health-related variables. Nonetheless, this simple test provides a marker which could be a valuable addition to understanding population and individual-level risk.

Journal article

Penn MJ, Donnelly CA, 2023, Optimality of maximal-effort vaccination, Bulletin of Mathematical Biology, Vol: 85, Pages: 1-71, ISSN: 0092-8240

It is widely acknowledged that vaccinating at maximal effort in the face of an ongoing epidemic is the best strategy to minimise infections and deaths from the disease. Despite this, no one has proved that this is guaranteed to be true if the disease follows multi-group SIR (Susceptible-Infected-Recovered) dynamics. This paper provides a novel proof of this principle for the existing SIR framework, showing that the total number of deaths or infections from an epidemic is decreasing in vaccination effort. Furthermore, it presents a novel model for vaccination which assumes that vaccines assigned to a subgroup are distributed randomly to the unvaccinated population of that subgroup. It suggests, using COVID-19 data, that this more accurately captures vaccination dynamics than the model commonly found in the literature. However, as the novel model provides a strictly larger set of possible vaccination policies, the results presented in this paper hold for both models.

Journal article

Eales O, de Oliveira Martins L, Page A, Wang H, Bodinier B, Tang D, Haw D, Jonnerby LJA, Atchison C, Ashby D, Barclay W, Taylor G, Cooke G, Ward H, Darzi A, Riley S, Elliott P, Donnelly C, Chadeau Met al., 2023, Dynamics and scale of the SARS-CoV-2 variant Omicron epidemic in England, Nature Communications, Vol: 13, ISSN: 2041-1723

The SARS-CoV-2 pandemic has been characterised by the regular emergence of genomic variants. With natural and vaccine-induced population immunity at high levels, evolutionary pressure favours variants better able to evade SARS-CoV-2 neutralising antibodies. The Omicron variant (first detected in November 2021) exhibited a high degree of immune evasion, leading to increased infection rates worldwide. However, estimates of the magnitude of this Omicron wave have often relied on routine testing data, which are prone to several biases. Using data from the REal-time Assessment of Community Transmission-1 (REACT-1) study, a series of cross-sectional surveys assessing prevalence of SARS-CoV-2 infection in England, we estimated the dynamics of England’s Omicron wave (from 9 September 2021 to 1 March 2022). We estimate an initial peak in national Omicron prevalence of 6.89% (5.34%, 10.61%) during January 2022, followed by a resurgence in SARS-CoV-2 infections as the more transmissible Omicron sub-lineage, BA.2 replaced BA.1 and BA.1.1. Assuming the emergence of further distinct variants, intermittent epidemics of similar magnitudes may become the ‘new normal’.

Journal article

Griffee MJ, Bozza PT, Reyes LF, Eddington DP, Rosenberger D, Merson L, Citarella BW, Fanning JP, Alexander PMA, Fraser J, Dalton H, Cho S-M, ISARIC Clinical Characterisation Groupet al., 2023, Thrombotic and hemorrhagic complications of COVID-19 in adults hospitalized in high-income countries compared with those in adults hospitalized in low- and middle-income countries in an international registry., Res Pract Thromb Haemost, Vol: 7

BACKGROUND: COVID-19 has been associated with a broad range of thromboembolic, ischemic, and hemorrhagic complications (coagulopathy complications). Most studies have focused on patients with severe disease from high-income countries (HICs). OBJECTIVES: The main aims were to compare the frequency of coagulopathy complications in developing countries (low- and middle-income countries [LMICs]) with those in HICs, delineate the frequency across a range of treatment levels, and determine associations with in-hospital mortality. METHODS: Adult patients enrolled in an observational, multinational registry, the International Severe Acute Respiratory and Emerging Infections COVID-19 study, between January 1, 2020, and September 15, 2021, met inclusion criteria, including admission to a hospital for laboratory-confirmed, acute COVID-19 and data on complications and survival. The advanced-treatment cohort received care, such as admission to the intensive care unit, mechanical ventilation, or inotropes or vasopressors; the basic-treatment cohort did not receive any of these interventions. RESULTS: The study population included 495,682 patients from 52 countries, with 63% from LMICs and 85% in the basic treatment cohort. The frequency of coagulopathy complications was higher in HICs (0.76%-3.4%) than in LMICs (0.09%-1.22%). Complications were more frequent in the advanced-treatment cohort than in the basic-treatment cohort. Coagulopathy complications were associated with increased in-hospital mortality (odds ratio, 1.58; 95% CI, 1.52-1.64). The increased mortality associated with these complications was higher in LMICs (58.5%) than in HICs (35.4%). After controlling for coagulopathy complications, treatment intensity, and multiple other factors, the mortality was higher among patients in LMICs than among patients in HICs (odds ratio, 1.45; 95% CI, 1.39-1.51). CONCLUSION: In a large, international registry of patients hospitalized for COVID-19, coagulopathy complications were mo

Journal article

Penn MJJ, Laydon DJJ, Penn J, Whittaker C, Morgenstern C, Ratmann O, Mishra S, Pakkanen MSS, Donnelly CAA, Bhatt Set al., 2023, Intrinsic randomness in epidemic modelling beyond statistical uncertainty, Communications Physics, Vol: 6, ISSN: 2399-3650

Uncertainty can be classified as either aleatoric (intrinsic randomness) or epistemic (imperfect knowledge of parameters). The majority of frameworks assessing infectious disease risk consider only epistemic uncertainty. We only ever observe a single epidemic, and therefore cannot empirically determine aleatoric uncertainty. Here, we characterise both epistemic and aleatoric uncertainty using a time-varying general branching process. Our framework explicitly decomposes aleatoric variance into mechanistic components, quantifying the contribution to uncertainty produced by each factor in the epidemic process, and how these contributions vary over time. The aleatoric variance of an outbreak is itself a renewal equation where past variance affects future variance. We find that, superspreading is not necessary for substantial uncertainty, and profound variation in outbreak size can occur even without overdispersion in the offspring distribution (i.e. the distribution of the number of secondary infections an infected person produces). Aleatoric forecasting uncertainty grows dynamically and rapidly, and so forecasting using only epistemic uncertainty is a significant underestimate. Therefore, failure to account for aleatoric uncertainty will ensure that policymakers are misled about the substantially higher true extent of potential risk. We demonstrate our method, and the extent to which potential risk is underestimated, using two historical examples.

Journal article

Atchison C, Whitaker M, Donnelly C, Chadeau-Hyam M, Riley S, Darzi A, Ashby D, Barclay W, Cooke G, Elliott P, Ward Het al., 2023, Characteristics and predictors of persistent symptoms post COVID-19 in children and young people: a large community cross-sectional study in England, Archives of Disease in Childhood, Vol: 108, ISSN: 0003-9888

Objective: To estimate the prevalence of, and associated risk factors for, persistent symptoms post-COVID-19 among children aged 5–17 years in England.Design: Serial cross-sectional study.Setting: Rounds 10–19 (March 2021 to March 2022) of the REal-time Assessment of Community Transmission-1 study (monthly cross-sectional surveys of random samples of the population in England).Study population: Children aged 5–17 years in the community.Predictors: Age, sex, ethnicity, presence of a pre-existing health condition, index of multiple deprivation, COVID-19 vaccination status and dominant UK circulating SARS-CoV-2 variant at time of symptom onset.Main outcome measures: Prevalence of persistent symptoms, reported as those lasting ≥3 months post-COVID-19.Results: Overall, 4.4% (95% CI 3.7 to 5.1) of 3173 5–11 year-olds and 13.3% (95% CI 12.5 to 14.1) of 6886 12–17 year-olds with prior symptomatic infection reported at least one symptom lasting ≥3 months post-COVID-19, of whom 13.5% (95% CI 8.4 to 20.9) and 10.9% (95% CI 9.0 to 13.2), respectively, reported their ability to carry out day-to-day activities was reduced ‘a lot’ due to their symptoms. The most common symptoms among participants with persistent symptoms were persistent coughing (27.4%) and headaches (25.4%) in children aged 5–11 years and loss or change of sense of smell (52.2%) and taste (40.7%) in participants aged 12–17 years. Higher age and having a pre-existing health condition were associated with higher odds of reporting persistent symptoms.Conclusions: One in 23 5–11 year-olds and one in eight 12–17 year-olds post-COVID-19 report persistent symptoms lasting ≥3 months, of which one in nine report a large impact on performing day-to-day activities.

Journal article

McCabe R, Sheppard R, Abdelmagid N, Ahmed A, Alabdeen IZ, Brazeau N, Abd Elhameed AEA, Bin-Ghouth AS, Hamlet A, AbuKoura R, Barnsley G, Hay J, Alhaffar M, Besson EK, Saje SM, Sisay BG, Gebreyesus SH, Sikamo AP, Worku A, Ahmed YS, Mariam DH, Sisay MM, Checchi F, Dahab M, Endris BS, Ghani A, Walker P, Donnelly C, Watson Oet al., 2023, Alternative epidemic indicators for COVID-19 in three settings with incomplete death registration systems, Science Advances, Vol: 23, Pages: 1-10, ISSN: 2375-2548

Not all COVID-19 deaths are officially reported, and particularly in low-income and humanitarian settings, the magnitude of reporting gaps remains sparsely characterized. Alternative data sources, including burial site worker reports, satellite imagery of cemeteries, and social media–conducted surveys of infection may offer solutions. By merging these data with independently conducted, representative serological studies within a mathematical modeling framework, we aim to better understand the range of underreporting using examples from three major cities: Addis Ababa (Ethiopia), Aden (Yemen), and Khartoum (Sudan) during 2020. We estimate that 69 to 100%, 0.8 to 8.0%, and 3.0 to 6.0% of COVID-19 deaths were reported in each setting, respectively. In future epidemics, and in settings where vital registration systems are limited, using multiple alternative data sources could provide critically needed, improved estimates of epidemic impact. However, ultimately, these systems are needed to ensure that, in contrast to COVID-19, the impact of future pandemics or other drivers of mortality is reported and understood worldwide.

Journal article

Wainstein M, Spyrison N, Dai D, Ghadimi M, Chávez-Iñiguez JS, Rizo-Topete L, Citarella BW, Merson L, Pole JD, Claure-Del Granado R, Johnson DW, Shrapnel S, ISARIC Characterization Groupet al., 2023, Association of Country Income Level With the Characteristics and Outcomes of Critically Ill Patients Hospitalized With Acute Kidney Injury and COVID-19., Kidney Int Rep, Vol: 8, Pages: 1514-1530

INTRODUCTION: Acute kidney injury (AKI) has been identified as one of the most common and significant problems in hospitalized patients with COVID-19. However, studies examining the relationship between COVID-19 and AKI in low- and low-middle income countries (LLMIC) are lacking. Given that AKI is known to carry a higher mortality rate in these countries, it is important to understand differences in this population. METHODS: This prospective, observational study examines the AKI incidence and characteristics of 32,210 patients with COVID-19 from 49 countries across all income levels who were admitted to an intensive care unit during their hospital stay. RESULTS: Among patients with COVID-19 admitted to the intensive care unit, AKI incidence was highest in patients in LLMIC, followed by patients in upper-middle income countries (UMIC) and high-income countries (HIC) (53%, 38%, and 30%, respectively), whereas dialysis rates were lowest among patients with AKI from LLMIC and highest among those from HIC (27% vs. 45%). Patients with AKI in LLMIC had the largest proportion of community-acquired AKI (CA-AKI) and highest rate of in-hospital death (79% vs. 54% in HIC and 66% in UMIC). The association between AKI, being from LLMIC and in-hospital death persisted even after adjusting for disease severity. CONCLUSIONS: AKI is a particularly devastating complication of COVID-19 among patients from poorer nations where the gaps in accessibility and quality of healthcare delivery have a major impact on patient outcomes.

Journal article

Eales O, Haw D, Wang H, Atchison C, Ashby D, Cooke GS, Barclay W, Ward H, Darzi A, Donnelly CA, Chadeau-Hyam M, Elliott P, Riley Set al., 2023, Dynamics of SARS-CoV-2 infection hospitalisation and infection fatality ratios over 23 months in England, PLoS Biology, Vol: 21, Pages: 1-21, ISSN: 1544-9173

The relationship between prevalence of infection and severe outcomes such as hospitalisation and death changed over the course of the COVID-19 pandemic. Reliable estimates of the infection fatality ratio (IFR) and infection hospitalisation ratio (IHR) along with the time-delay between infection and hospitalisation/death can inform forecasts of the numbers/timing of severe outcomes and allow healthcare services to better prepare for periods of increased demand. The REal-time Assessment of Community Transmission-1 (REACT-1) study estimated swab positivity for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in England approximately monthly from May 2020 to March 2022. Here, we analyse the changing relationship between prevalence of swab positivity and the IFR and IHR over this period in England, using publicly available data for the daily number of deaths and hospitalisations, REACT-1 swab positivity data, time-delay models, and Bayesian P-spline models. We analyse data for all age groups together, as well as in 2 subgroups: those aged 65 and over and those aged 64 and under. Additionally, we analysed the relationship between swab positivity and daily case numbers to estimate the case ascertainment rate of England's mass testing programme. During 2020, we estimated the IFR to be 0.67% and the IHR to be 2.6%. By late 2021/early 2022, the IFR and IHR had both decreased to 0.097% and 0.76%, respectively. The average case ascertainment rate over the entire duration of the study was estimated to be 36.1%, but there was some significant variation in continuous estimates of the case ascertainment rate. Continuous estimates of the IFR and IHR of the virus were observed to increase during the periods of Alpha and Delta's emergence. During periods of vaccination rollout, and the emergence of the Omicron variant, the IFR and IHR decreased. During 2020, we estimated a time-lag of 19 days between hospitalisation and swab positivity, and 26 days between deaths

Journal article

Donnelly CA, 2023, Sir David Cox—A Life Well Lived, Issue 5.2, Spring 2023, Vol: 5

Journal article

Cho S-M, White N, Premraj L, Battaglini D, Fanning J, Suen J, Bassi GL, Fraser J, Robba C, Griffee M, Singh B, Citarella BW, Merson L, Solomon T, Thomson D, ISARIC Clinical Characterisation Groupet al., 2023, Neurological manifestations of COVID-19 in adults and children, Brain, Vol: 146, Pages: 1648-1661, ISSN: 1460-2156

Different neurological manifestations of coronavirus disease 2019 (COVID-19) in adults and children and their impact have not been well characterized. We aimed to determine the prevalence of neurological manifestations and in-hospital complications among hospitalized COVID-19 patients and ascertain differences between adults and children. We conducted a prospective multicentre observational study using the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) cohort across 1507 sites worldwide from 30 January 2020 to 25 May 2021. Analyses of neurological manifestations and neurological complications considered unadjusted prevalence estimates for predefined patient subgroups, and adjusted estimates as a function of patient age and time of hospitalization using generalized linear models. Overall, 161 239 patients (158 267 adults; 2972 children) hospitalized with COVID-19 and assessed for neurological manifestations and complications were included. In adults and children, the most frequent neurological manifestations at admission were fatigue (adults: 37.4%; children: 20.4%), altered consciousness (20.9%; 6.8%), myalgia (16.9%; 7.6%), dysgeusia (7.4%; 1.9%), anosmia (6.0%; 2.2%) and seizure (1.1%; 5.2%). In adults, the most frequent in-hospital neurological complications were stroke (1.5%), seizure (1%) and CNS infection (0.2%). Each occurred more frequently in intensive care unit (ICU) than in non-ICU patients. In children, seizure was the only neurological complication to occur more frequently in ICU versus non-ICU (7.1% versus 2.3%, P < 0.001). Stroke prevalence increased with increasing age, while CNS infection and seizure steadily decreased with age. There was a dramatic decrease in stroke over time during the pandemic. Hypertension, chronic neurological disease and the use of extracorporeal membrane oxygenation were associated with increased risk of stroke. Altered consciousness was associated with CNS infection, seizure and stroke.

Journal article

Kim Y, Donnelly CA, Nouvellet P, 2023, Drivers of SARS-CoV-2 testing behaviour: a modelling study using nationwide testing data in England, NATURE COMMUNICATIONS, Vol: 14

Journal article

Elliott P, Whitaker M, Tang D, Eales O, Steyn N, Bodinier B, Wang H, Elliott J, Atchison C, Ashby D, Barclay W, Taylor G, Darzi A, Cooke G, Ward H, Donnelly C, Riley S, Chadeau Met al., 2023, Design and implementation of a national SARS-CoV-2 monitoring programme in England: REACT-1 Study, American Journal of Public Health, ISSN: 0090-0036

Data System. The REal-time Assessment of Community Transmission-1 (REACT-1) Study was funded by the Department of Health and Social Care in England to provide reliable and timely estimates of prevalence of SARS-CoV-2 infection by time, person and place.Data Collection/Processing. The data were obtained by writing to named individuals aged 5 years and above in random cross-sections of the population of England, using the National Health Service (NHS) list of patients registered with a general practitioner (>99% coverage) as sampling frame. Data were collected 2-3 weekly approximately every month across 19distinct rounds of data collection from May 1, 2020 to March 31, 2022.Data Analysis/Dissemination. The data and study materials are widely disseminated via the study website, preprints, publications in peer-reviewed journals and the media. Data tabulations suitably anonymised to protect participant confidentiality are available on request to the study’s Data Access Committee.Implications. The study provided inter alia real-time data on SARS-CoV-2 prevalence over time, by area, and by socio-demographic variables; estimates of vaccine effectiveness; symptom profiles and detected emergence of new variants based on viral genome sequencing.

Journal article

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