ProfessorTimothy Hallett

My work has focussed on using analytic methods to understand how resources can be used to maximise population health.

In early work in HIV, I showed how PrEP and ART can be used in tandem to the greatest effect [1] and how a spatial targeting of interventions can radically increase their efficiency [2], which fed into funding policy. I also developed several methods by which the HIV epidemic is monitored, which are adopted by WHO/UNAIDS [e.g., 3]. With the HIV Modelling Consortium, I led the critical evaluations of the expansion for criteria of ART [4-5] that fed into two rounds of WHO guidance updates.

I have also worked extensively in other fields of health, including HBV [6], HCV [7], where my work established the WHO and UN targets; and for HIV, TB and malaria [8], including my work with Global Fund to develop the ‘Investment Cases’ for each replenishment [9].

My interest in multi-disease interactions and patient-centred care began when I examined the build-up of comorbidities in persons living with HIV [10]. This led to further work in healthcare system modelling, where I have pioneered the development of the Thanzi La Onse Model [11], which has spurred many other analyses at the intersection of epidemiology, health-economics and system research.

My publications (>200 items) have attracted >24,000 citations and an h-index of 77.


Selected Publications

[1] Hallett, T. B., Baeten, J. M., Heffron, R., Barnabas, R., de Bruyn, G., Cremin, I., . . . Celum, C. (2011). Optimal Uses of Antiretrovirals for Prevention in HIV-1 Serodiscordant Heterosexual Couples in South Africa: A Modelling Study. PLOS MEDICINE, 8(11), 12 pages. doi:10.1371/journal.pmed.1001123

[2] Anderson, S. -J., Cherutich, P., Kilonzo, N., Cremin, I., Fecht, D., Kimanga, D., . . . Hallett, T. B. (2014). Maximising the effect of combination HIV prevention through prioritisation of the people and places in greatest need: a modelling study. LANCET,384(9939), 249-256. doi:10.1016/S0140-6736(14)61053-9

[3] Hallett, T. B., Zaba, B., Todd, J., Lopman, B., Mwita, W., Biraro, S., . . . Boerma, J. T. (2008). Estimating incidence from prevalence in generalised HIV epidemics: Methods and validation. PLOS MEDICINE, 5(4), 611-622. doi:10.1371/journal.pmed.0050080

[4] Eaton, J. W., Menzies, N. A., Stover, J., Cambiano, V., Chindelevitch, L., Cori, A., . . . Hallett, T. B. (2014). Health benefits, costs, and cost-effectiveness of earlier eligibility for adult antiretroviral therapy and expanded treatment coverage: a combined analysis of 12 mathematical models. LANCET GLOBAL HEALTH, 2(1), E23-E34. doi:10.1016/S2214-109X(13)70172-4

[5] Keebler, D., Revill, P., Braithwaite, S., Phillips, A., Blaser, N., Borquez, A., . . . Hallett, T. B. (2014). Cost-effectiveness of different strategies to monitor adults on antiretroviral treatment: a combined analysis of three mathematical models. LANCET GLOBAL HEALTH, 2(1), E35-E43. doi:10.1016/S2214-109X(13)70048-2

[6] Nayagam, S., Thursz, M., Sicuri, E., Conteh, L., Wiktor, S., Low-Beer, D., & Hallett, T. B. (2016). Requirements for global elimination of hepatitis B: a modelling study. LANCET INFECTIOUS DISEASES, 16(12), 1399-1408. doi:10.1016/S1473-3099(16)30204-3

[7] Heffernan, A., Cooke, G. S., Nayagam, S., Thursz, M., & Hallett, T. B. (2019). Scaling up prevention and treatment towards the elimination of hepatitis C: a global mathematical model. LANCET, 393(10178), 1319-1329. doi:10.1016/S0140-6736(18)32277-3

[8] Hogan A, Jewell B, Sherrard-Smith E, Watson O, Whittaker C, Hamlet A, … , Hallett TB, 2020, Potential impact of the COVID-19 pandemic on HIV, TB and malaria in low- and middle-income countries: a modelling study, LANCET GLOBAL HEALTH (8):e1132-e1141, ISSN: 2214-109X DOI: 10.1016/S2352-3018(20)30211-3

[9] Hallett TB, Menzies NA, Resch S, et al. The case for optimal investment in combating HIV, tuberculosis, and malaria: a global modelling study. The Lancet 2025; 0. DOI:10.1016/S0140-6736(25)00831-1.

[10] Smit, M., Brinkman, K., Geerlings, S., Smit, C., Thyagarajan, K., van Sighem, A., . . . Hallett, T. B. (2015). Future challenges for clinical care of an ageing population infected with HIV: a modelling study. LANCET INFECTIOUS DISEASES, 15(7), 810-818. doi:10.1016/S1473-3099(15)00056-0

[11] Hallett TB, Mangal TD, Tamuri AU, Arinaminpathy N, Cambiano V, Chalkley M, et al. (2024) Estimates of resource use in the public-sector health-care system and the effect of strengthening health-care services in Malawi during 2015–19: a modelling study (Thanzi La Onse). The Lancet Global Health. doi:10.1016/S2214-109X(24)00413-3.