Imperial College London


Faculty of MedicineSchool of Public Health

Senior Lecturer & Royal Society Dorothy Hodgkin Fellow



l.okell Website




410School of Public HealthWhite City Campus





My research interests are the development of mathematical models of malaria and analysis of epidemiological data in collaboration with policy-makers to better understand malaria burden, the impact of public health interventions and to inform malaria control policy.

I currently hold a Royal Society Dorothy Hodgkin Fellowship and my research focuses on assessing use of different types of antimalarial treatments in Africa and their impact on community-wide transmission, prophylaxis, and the international spread of drug resistant Plasmodium falciparum malaria. I also have have a particular interest in the contribution of low density malaria infections to sustaining transmission.

The effect of a given malaria control intervention can often vary between different epidemiological settings, and I have applied models to specific endemic settings in Africa in collaboration with field-based staff and policy makers in order to understand where and under what conditions different strategies can be most appropriate.


Selected Publications

Journal Articles

Winskill P, Dhabangi A, Kwambai TK, et al., 2023, Estimating the burden of severe malarial anaemia and access to hospital care in East Africa., Nat Commun, Vol:14

Okell LC, Kwambai TK, Dhabangi A, et al., 2023, Projected health impact of post-discharge malaria chemoprevention among children with severe malarial anaemia in Africa, Nature Communications, Vol:14, ISSN:2041-1723, Pages:1-10

Challenger J, Foo C, Wu Y, et al., 2022, Modelling upper respiratory viral load dynamics of SARS-CoV-2, BMC Medicine, Vol:20, ISSN:1741-7015

Okell L, Whittaker C, Ghani A, et al., 2021, Global patterns of submicroscopic Plasmodium falciparum malaria infection: insights from a systematic review and meta-analysis of population surveys, The Lancet Microbe, Vol:2, ISSN:2666-5247, Pages:e366-e374

Winskill P, Mousa A, Oresanya O, et al., 2021, Does integrated community case management (iCCM) target health inequities and treatment delays? Evidence from an analysis of Demographic and Health Surveys data from 21 countries in the period 2010 to 2018, Journal of Global Health, Vol:11, ISSN:2047-2978, Pages:1-10

Witmer K, Dahalan F, Delves M, et al., 2021, Transmission of artemisinin-resistant malaria parasites to mosquitoes under antimalarial drug pressure, Antimicrobial Agents and Chemotherapy, Vol:65, ISSN:0066-4804, Pages:1-17

Mousa A, Al-Taiar A, Anstey NM, et al., 2020, The impact of delayed treatment of uncomplicated P. falciparum malaria on progression to severe malaria: a systematic review and a pooled multicentre individual-patient meta-analysis, PLOS Medicine, Vol:17, ISSN:1549-1277, Pages:1-28

Watson O, Okell L, Hellewell J, et al., 2020, Evaluating the performance of malaria genetics for inferring changes in transmission intensity using transmission modelling, Molecular Biology and Evolution, Vol:38, ISSN:0737-4038, Pages:274-289

Hogan A, Jewell B, Sherrard-Smith E, et al., 2020, Potential impact of the COVID-19 pandemic on HIV, TB and malaria in low- and middle-income countries: a modelling study, The Lancet Global Health, Vol:8, ISSN:2214-109X, Pages:e1132-e1141

Flaxman S, Mishra S, Gandy A, et al., 2020, Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe, Nature, Vol:584, ISSN:0028-0836, Pages:257-261

Sherrard-Smith E, Hogan AB, Hamlet A, et al., 2020, The potential public health consequences of COVID-19 on malaria in Africa., Nature Medicine, Vol:26, ISSN:1078-8956, Pages:1411-1416

Okell LC, Verity R, Watson OJ, et al., 2020, Have deaths from COVID-19 in Europe plateaued due to herd immunity?, The Lancet, Vol:395, ISSN:0140-6736, Pages:E110-E111

Verity R, Okell LC, Dorigatti I, et al., 2020, Estimates of the severity of coronavirus disease 2019: a model-based analysis., Lancet Infectious Diseases, Vol:20, ISSN:1473-3099, Pages:669-677

Okell L, Bretscher MT, Dahal P, et al., 2020, The duration of chemoprophylaxis against malaria after treatment with artesunate-amodiaquine and artemether-lumefantrine and the effects of pfmdr1 86Y and pfcrt 76T: a meta-analysis of individual patient data, BMC Medicine, Vol:18, ISSN:1741-7015, Pages:1-17

Challenger J, Goncalves BP, Bradley J, et al., 2019, How delayed and non-adherent treatment contribute to onward transmission of malaria: a modelling study, Bmj Global Health, Vol:4, ISSN:2059-7908

van Eijk AM, Larsen DA, Kayentao K, et al., 2019, Effect of Plasmodium falciparum sulfadoxine-pyrimethamine resistance on the effectiveness of intermittent preventive therapy for malaria in pregnancy in Africa: a systematic review and meta-analysis., Lancet Infectious Diseases, Vol:19, ISSN:1473-3099, Pages:546-556

Slater H, Ross A, Felger I, et al., 2019, The temporal dynamics and infectiousness of subpatent Plasmodium falciparum infections in relation to parasite density, Nature Communications, Vol:10, ISSN:2041-1723

Okell L, Reiter LM, Ebbe LS, et al., 2018, Emerging implications of policies on malaria treatment: genetic changes in the Pfmdr-1 gene affecting susceptibility to artemether-lumefantrine and artesunate-amodiaquine in Africa, Bmj Global Health, Vol:3, ISSN:2059-7908

Challenger J, Bruxvoort K, Ghani AC, et al., 2017, Assessing the impact of imperfect adherence to artemether-lumefantrine on malaria treatment outcomes using within-host modelling, Nature Communications, Vol:8, ISSN:2041-1723

Bretscher MT, Griffin JT, Ghani AC, et al., 2017, Modelling the benefits of long-acting or transmission-blocking drugs for reducing Plasmodium falciparum transmission by case management or by mass treatment, Malaria Journal, Vol:16, ISSN:1475-2875

Okell L, Griffin JT, Roper C, 2017, Mapping sulphadoxine-pyrimethamine-resistant Plasmodium falciparum malaria in infected humans and in parasite populations in Africa, Scientific Reports, Vol:7, ISSN:2045-2322

Brady OJ, Slater HC, Pemberton-Ross P, et al., 2017, Role of mass drug administration in elimination of Plasmodium falciparum malaria: a consensus modelling study, The Lancet Global Health, Vol:5, ISSN:2214-109X, Pages:E680-E687

Okell LC, Churcher TS, 2016, Generating the evidence base for malaria elimination: the situation in Haiti, Lancet Global Health, Vol:5, ISSN:2214-109X, Pages:e16-e17

Slater HC, Okell LC, Ghani AC, 2016, Mathematical Modelling to Guide Drug Development for Malaria Elimination, Trends in Parasitology, Vol:33, ISSN:1471-5007, Pages:175-184

Slater HC, Griffin JT, Ghani AC, et al., 2016, Assessing the potential impact of artemisinin and partner drug resistance in sub-Saharan Africa., Malaria Journal, Vol:15, ISSN:1475-2875

Wu L, van den Hoogen LL, Slater H, et al., 2015, Comparison of diagnostics for the detection of asymptomatic Plasmodium falciparum infections to inform control and elimination strategies, Nature, Vol:528, ISSN:0028-0836, Pages:S86-S93

Bousema T, Okell L, Felger I, et al., 2014, Asymptomatic malaria infections: detectability, transmissibility and public health relevance, Nature Reviews Microbiology, Vol:12, ISSN:1740-1526, Pages:833-840

Okell LC, Cairns M, Griffin JT, et al., 2014, Contrasting benefits of different artemisinin combination therapies as first-line malaria treatments using model-based cost-effectiveness analysis, Nature Communications, Vol:5, ISSN:2041-1723

Okell LC, Bousema T, Griffin JT, et al., 2012, Factors determining the occurrence of submicroscopic malaria infections and their relevance for control, Nature Communications, Vol:3, ISSN:2041-1723

Okell LC, Griffin JT, Kleinschmidt I, et al., 2011, The Potential Contribution of Mass Treatment to the Control of <i>Plasmodium falciparum</i> Malaria, PLOS One, Vol:6, ISSN:1932-6203

Griffin JT, Hollingsworth TD, Okell LC, et al., 2010, Reducing Plasmodium falciparum malaria transmission in Africa: a model-based evaluation of intervention strategies., Plos Med, Vol:7, ISSN:1549-1676, Pages:1-27

Bousema T, Okell L, Shekalaghe S, et al., 2010, Revisiting the circulation time of Plasmodium falciparum gametocytes: molecular detection methods to estimate the duration of gametocyte carriage and the effect of gametocytocidal drugs, Malaria Journal, Vol:9, ISSN:1475-2875

Okell LC, Ghani AC, Lyons E, et al., 2009, Submicroscopic infection in Plasmodium falciparum-endemic populations: a systematic review and meta-analysis, J Infect Dis, Vol:200, ISSN:1537-6613, Pages:1509-1517

Okell LC, Drakeley CJ, Bousema T, et al., 2008, Modelling the impact of artemisinin combination therapy and long-acting treatments on malaria transmission intensity, Plos Med, Vol:5, ISSN:1549-1676, Pages:e226-e226

More Publications