Sarah Walker, Professor of Medical Statistics & Epidemiology

Sarah has worked at the Unit since its initiation in 1999, having previously worked at the MRC HIV Clinical Trials Centre since 1994. Her work includes the design and analysis of clinical trials and observational studies of treatment and management strategies for HIV and other infectious diseases, including serious bacterial infections and Hepatitis C. She has worked on projects involving both adults and children, in high-income and low/middle-income countries. Methdological research interests include the use of causal models to address additional non-randomised questions using data from clinical trials.

From April 2006, Sarah has worked part-time at the University of Oxford, predominantly with the NIHR Oxford Biomedical Centre Infections Theme and the "Modernising Medical Microbiology" Consortium translating new whole genome sequencing approaches into microbiology practice and service and investigating electronic health records for infectious diseases research.

Sarah is also Associate Statistical Editor for the Journal of Infectious Diseases.

Selected publications

Bwakura-Dangarembizi M, Kendall L, Bakeera-Kitaka S, Nahirya-Ntege P, Keishanyu R, Nathoo K, Spyer MJ, Kekitiinwa A, Lutaakome J, Mhute T, Kasirye P, Munderi P, Musiime V, Gibb DM*, Walker AS*, Prendergast AJ* and the ARROW Trial Team. A randomized trial of prolonged cotrimoxazole in HIV-infected children in Africa. N Engl J Med 2014; 370: 41-53. *contributed equally.

Paton NI, Kityo C, Hoppe A, Reid A, Kambugu A, Lugemwa A, van Oosterhout J, Kiconco M, Siika A, Mwebaze R, Abwola M, Abongomera G, Mweemba A, Alima H, Atwongyeire D, Nyirenda R, Boles J, Thompson J, Tumukunde D, Chidziva E, Mambule I, Arribas JR, Easterbrook PJ, Hakim J, Walker AS*, Mugyenyi P* for the EARNEST Trial Team. Assessment of second-line antiretroviral regimens for HIV therapy in Africa. N Eng J Med 2014;371(3):234-47.

Eyre DW, Cule ML, Wilson DJ, Griffiths D, Vaughan A, O'Connor L, Ip CLC, Golubchik T, Batty EM, Didelot X, Piazza P, Bowden R, Dingle KE, Harding RM, Crook DW, Wilcox MH*, Peto TEA*, Walker AS*. Diverse sources of C. difficile infection identified on whole genome sequencing. N Eng J Med 2013;369(13):1195-205. doi: 10.1056/NEJMoa1216064.

Walker AS, Ford D, Gilks C, Munderi P, Ssali F, Reid A, Katabira E, Grosskurth H, Mugyenyi P, Hakim J, Darbyshire JH, Gibb DM, Babiker AG. Daily co-trimoxazole prophylaxis in severely immunosuppressed HIV-infected adults in Africa started on combination antiretroviral therapy: an observational analysis of the DART cohort. Lancet 2010;375:1278-86.

ARROW Trial Team. ARROW: a 5-year randomised factorial trial of routine versus clinically driven laboratory monitoring and first-line antiretroviral therapy strategies in HIV-infected African children. Lancet 2013; 381(9875):1391-403. doi: 10.1016/S0140-6736(12)62198-9.

Ford DJ, Robins J, Petersen M, Gibb DM, Gilks CF, Mugyenyi P, Grosskurth H, Hakim J, Katabira E, Babiker AG, Walker AS on behalf of the DART trial team. The impact of different CD4 monitoring and switching strategies on mortality in HIV-infected African adults on antiretroviral therapy; an application of dynamic marginal structural models. American Journal of Epidemiology 2015;182(7):633-43. doi: 10.1093/aje/kwv083.

Thwaites G, Auckland C, Barlow G, Cunningham R, Davis G, Edgeworth J, Hopkins S, Jeyaratnam D, Jenkins N, Llewelyn M, Meisner S, Nsutebu E, Planche T, Read R, Scarborough M, Soares M, Tilley R, Torok E, Williams J, Wilson P, Wyllie S, Walker AS on behalf of the United Kingdom Clinical Infection Research Group. Adjunctive rifampicin to reduce early mortality from Staphylococcus aureus bacteraemia (ARREST): study protocol for a multi-centre, randomised, blinded, placebo controlled trial. Trials 2012; ;13:241. doi: 10.1186/1745-6215-13-241.

Mead S, Burnell M, Lowe J, Thompson A, Lukic A, Porter MC, Carswell C, Kaski D, Kenny J, TzeHow M, Bjurstrom N, Gorham M, Druyeh R, Wadsworth J, Jaunmuktane Z, Brandner S, Hyare H, Rudge R, Walker AS*, Collinge J*. Clinical trial simulations based on genetic stratification and the natural history of a functional outcome measure in Creutzfeldt-Jakob disease. JAMA Neurology 2016;73(4):447-55.

Picat MQ*, Lewis J*, Musiime V, Prendergast A, Nathoo K, Kekitiinwa A, Nahirya Ntege P, Gibb DM, Thiebaut R, Walker AS**, Klein N**, Callard R** and the ARROW Trial Team. Predicting patterns of long-term CD4 reconstitution in HIV-infected children starting antiretroviral therapy in Sub-Saharan Africa: a cohort-based modelling study. Plos Med 2013; 10(10): e1001542. doi:10.1371/journal.pmed.1001542. */** contributed equally.

Walker AS, Prendergast A, Mugyenyi P, Munderi P, Hakim J, Kekitiinwa A, Katabira E, Gilks CF, Kityo C, Nahirya-Ntege P, Nathoo K, Gibb DM on behalf of the DART and ARROW trial teams. Early mortality following antiretroviral therapy initiation in HIV-infected adults and children in Uganda and Zimbabwe. Clin Infect Dis 2012;55:1707-1718.

Gibb DM, Kizito H, Russell EC, Chidziva E, Zalwango E, Nalumenya R, Spyer M, Tumukunde D, Nathoo K, Munderi P, Kyomugisha H, Hakim J, Grosskurth H, Gilks CF, Walker AS*, Musoke P* on behalf of the DART trial team. Pregnancy and infant outcomes among HIV-infected women taking long-term antiretroviral therapy with and without tenofovir in the DART trial. Plos Med 2012: e1001217. doi:10.1371/journal.pmed.1001217. *contributed equally.

Research Interests

  • HIV
  • Healthcare associated infections, particularly C. difficile
  • Transmission of C. difficile, tuberculosis, norovirus and S. aureus in the UK
  • Design of randomised trials and observational studies

Research Areas

  • HIV
  • Human prion disease
  • Paediatric infections (malaria/sepsis/tuberculosis)
  • Methodology