Imperial College London

DrIdeCremin

Faculty of MedicineSchool of Public Health

Honorary Research Associate
 
 
 
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Contact

 

+44 (0)20 7594 3631ide.cremin05

 
 
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Location

 

Norfolk PlaceSt Mary's Campus

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Summary

 

Publications

Publication Type
Year
to

19 results found

Cremin I, McKinnon L, Kimani J, Cherutich P, Gakii G, Muriuki F, Kripke K, Hecht R, Kiragu M, Smith J, Hinsley W, Gelmon L, Hallett Tet al., 2017, Including PrEP for key populations in combination HIV prevention: a mathematical modelling analysis of Nairobi as a case-study, Lancet HIV, Vol: 4, Pages: e214-e222, ISSN: 2405-4704

Background: The role of PrEP in combination HIV prevention remains uncertain. We aimed to identify an optimal portfolio of interventions to reduce HIV incidence for a given budget, and to identify the circumstances in which PrEP could be used in Nairobi, Kenya.Methods: A mathematical model was developed to represent HIV transmission among specific key populations (female sex workers (FSW), male sex workers (MSW), and men who have sex with men (MSM)) and among the wider population of Nairobi. The scale-up of existing interventions (condom promotion, anti-retroviral therapy (ART) and male circumcision) for key populations and the wider population as have occurred in Nairobi is represented. The model includes a detailed representation of a Pre-Exposure Prophylaxis (PrEP) intervention and is calibrated to prevalence and incidence estimates specific to key populations and the wider population. Findings: In the context of a declining epidemic overall but with a large sub-epidemic among MSM and MSW, an optimal prevention portfolio for Nairobi should focus on condom promotion for MSW and MSM in particular, followed by improved ART retention, earlier ART, and male circumcision as the budget allows. PrEP for MSW could enter an optimal portfolio at similar levels of spending to when earlier ART is included, however PrEP for MSM and FSW would be included only at much higher budgets. If PrEP for MSW cost as much $500, average annual spending on the interventions modelled would need to be less than $3·27 million for PrEP for MSW to be excluded from an optimal portfolio. Estimated costs per infection averted when providing PrEP to all FSW regardless of their risk of infection, and to high risk FSW only, are $65,160 (95% credible interval: $43,520 - $90,250) and $10,920 (95% credible interval: $4,700 - $51,560) respectively. Interpretation: PrEP could be a useful contribution to combination prevention, especially for underserved key populations in Nairobi. An ongoing demonst

Journal article

Cremin I, McKinnon L, Kimani J, Cherutich P, Gakii G, Muriuki F, Kripke K, Hecht R, Kiragu M, Smith J, Hinsley W, Gelmon L, Hallett TBet al., 2017, PrEP for key populations in combination HIV prevention in Nairobi: a mathematical modelling study, LANCET HIV, Vol: 4, Pages: E214-E222, ISSN: 2352-3018

Journal article

Cremin I, Morales F, Jewell BL, O'Reilly KR, Hallett TBet al., 2015, Seasonal PrEP for partners of migrant miners in southern Mozambique: a highly focused PrEP intervention, Journal of the International AIDS Society, Vol: 18, ISSN: 1758-2652

Introduction: To be used most effectively, pre-exposure prophylaxis (PrEP) should be prioritized to those at high risk of acquisition and would ideally be aligned with time periods of increased exposure. Identifying such time periods is not always straightforward, however. Gaza Province in southern Mozambique is characterized by high levels of HIV transmission and circular labour migration to mines in South Africa. A strong seasonal pattern in births is observable, reflecting an increase in conception in December. Given the potential for increased HIV transmission between miners returning in December and their partners in Gaza Province, PrEP use by the latter would be a useful means of HIV prevention, especially for couples who wish to conceive.Methods: A mathematical model was used to represent population-level adult heterosexual HIV transmission in Gaza Province. Increased HIV acquisition among partners of miners in December, coinciding with the miners’ return from South Africa, is represented. In addition to a PrEP intervention, the scale-up of treatment and recent scale-up of male circumcision that have occurred in Gaza are represented.Results: Providing time-limited PrEP to the partners of migrant miners, as opposed to providing PrEP all year, would improve the cost per infection averted by 7.5-fold. For the cost per infection averted to be below US$3000, at least 85% of PrEP users would need to be good adherers and PrEP would need to be cheaper than US$115 per person per year. Uncertainty regarding incidence of HIV transmission among partners of miners each year in December has a strong influence on estimates of cost per infection averted.Conclusions: Providing time-limited PrEP to partners of migrant miners in Gaza Province during periods of increased exposure would be a novel strategy for providing PrEP. This strategy would allow for a better prioritized intervention, with the potential to improve the efficiency of a PrEP intervention considerably, as

Journal article

Cremin I, Hallett TB, 2015, Estimating the range of potential epidemiological impact of pre-exposure prophylaxis: run-away success or run-away failure?, AIDS, Vol: 29, Pages: 733-738, ISSN: 0269-9370

Journal article

Jewell BL, Cremin I, Pickles M, Celum C, Baeten JM, Delany-Moretlwe S, Hallett TBet al., 2015, Estimating the cost-effectiveness of pre-exposure prophylaxis to reduce HIV-1 and HSV-2 incidence in HIV-serodiscordant couples in South Africa, PLOS One, Vol: 10, ISSN: 1932-6203

ObjectiveTo estimate the cost-effectiveness of daily oral tenofovir-based PrEP, with a protective effect against HSV-2 as well as HIV-1, among HIV-1 serodiscordant couples in South Africa.MethodsWe incorporated HSV-2 acquisition, transmission, and interaction with HIV-1 into a microsimulation model of heterosexual HIV-1 serodiscordant couples in South Africa, with use of PrEP for the HIV-1 uninfected partner prior to ART initiation for the HIV-1 1infected partner, and for one year thereafter.ResultsWe estimate the cost per disability-adjusted life-year (DALY) averted for two scenarios, one in which PrEP has no effect on reducing HSV-2 acquisition, and one in which there is a 33% reduction. After a twenty-year intervention, the cost per DALY averted is estimated to be $10,383 and $9,757, respectively – a 6% reduction, given the additional benefit of reduced HSV-2 acquisition. If all couples are discordant for both HIV-1 and HSV-2, the cost per DALY averted falls to $1,445, which shows that the impact is limited by HSV-2 concordance in couples.ConclusionAfter a 20-year PrEP intervention, the cost per DALY averted with a reduction in HSV-2 is estimated to be modestly lower than without any effect, providing an increase of health benefits in addition to HIV-1 prevention at no extra cost. The small degree of the effect is in part due to a high prevalence of HSV-2 infection in HIV-1 serodiscordant couples in South Africa.

Journal article

Anderson S-J, Cherutich P, Kilonzo N, Cremin I, Fecht D, Kimanga D, Harper M, Masha RL, Ngongo PB, Maina W, Dybul M, Hallett TBet al., 2014, Maximising the effect of combination HIV prevention through prioritisation of the people and places in greatest need: a modelling study, The Lancet, Vol: 384, Pages: 249-256, ISSN: 0140-6736

BackgroundEpidemiological data show substantial variation in the risk of HIV infection between communities within African countries. We hypothesised that focusing appropriate interventions on geographies and key populations at high risk of HIV infection could improve the effect of investments in the HIV response.MethodsWith use of Kenya as a case study, we developed a mathematical model that described the spatiotemporal evolution of the HIV epidemic and that incorporated the demographic, behavioural, and programmatic differences across subnational units. Modelled interventions (male circumcision, behaviour change communication, early antiretoviral therapy, and pre-exposure prophylaxis) could be provided to different population groups according to their risk behaviours or their location. For a given national budget, we compared the effect of a uniform intervention strategy, in which the same complement of interventions is provided across the country, with a focused strategy that tailors the set of interventions and amount of resources allocated to the local epidemiological conditions.FindingsA uniformly distributed combination of HIV prevention interventions could reduce the total number of new HIV infections by 40% during a 15-year period. With no additional spending, this effect could be increased by 14% during the 15 years—almost 100 000 extra infections, and result in 33% fewer new HIV infections occurring every year by the end of the period if the focused approach is used to tailor resource allocation to reflect patterns in local epidemiology. The cumulative difference in new infections during the 15-year projection period depends on total budget and costs of interventions, and could be as great as 150 000 (a cumulative difference as great as 22%) under different assumptions about the unit costs of intervention.InterpretationThe focused approach achieves greater effect than the uniform approach despite exactly the same investment. Through prioritisation of

Journal article

Jones A, Cremin I, Abdullah F, Idoko J, Cherutich P, Kilonzo N, Rees H, Hallett T, O'Reilly K, Koechlin F, Schwartlander B, de Zalduondo B, Kim S, Jay J, Huh J, Piot P, Dybul Met al., 2014, Transformation of HIV from pandemic to low-endemic levels: a public health approach to combination prevention, LANCET, Vol: 384, Pages: 272-279, ISSN: 0140-6736

Journal article

Cremin I, Alsallaq R, Dybul M, Piot P, Garnett G, Hallett TBet al., 2013, The new role of antiretrovirals in combination HIV prevention: a mathematical modelling analysis, AIDS, Vol: 27, Pages: 447-458, ISSN: 0269-9370

Journal article

Smit M, Smit C, Cremin I, Garnett GP, Hallett T, de Wolf Fet al., 2012, Could better tolerated HIV drug regimens improve patient outcome?, AIDS, Vol: 26, Pages: 1953-1959, ISSN: 0269-9370

Journal article

Cremin I, Cauchemez S, Garnett GP, Gregson Set al., 2012, Patterns of uptake of HIV testing in sub-Saharan Africa in the pre-treatment era, TROPICAL MEDICINE & INTERNATIONAL HEALTH, Vol: 17, Pages: e26-e37, ISSN: 1360-2276

Journal article

Chemaitelly H, Cremin I, Shelton J, Hallett TB, Abu-Raddad LJet al., 2012, Distinct HIV discordancy patterns by epidemic size in stable sexual partnerships in sub-Saharan Africa, SEXUALLY TRANSMITTED INFECTIONS, Vol: 88, Pages: 51-57, ISSN: 1368-4973

Journal article

Hallett TB, Baeten JM, Heffron R, Barnabas R, de Bruyn G, Cremin I, Delany S, Garnett GP, Gray G, Johnson L, McIntyre J, Rees H, Celum Cet al., 2011, Optimal Uses of Antiretrovirals for Prevention in HIV-1 Serodiscordant Heterosexual Couples in South Africa: A Modelling Study, PLOS MEDICINE, Vol: 8, ISSN: 1549-1676

Journal article

Cremin I, Nyamukapa C, Sherr L, Hallett TB, Chawira G, Cauchemez S, Lopman B, Garnett GP, Gregson Set al., 2010, Patterns of Self-reported Behaviour Change Associated with Receiving Voluntary Counselling and Testing in a Longitudinal Study from Manicaland, Zimbabwe, AIDS AND BEHAVIOR, Vol: 14, Pages: 708-715, ISSN: 1090-7165

Journal article

Todd J, Cremin I, McGrath N, Bwanika J-B, Wringe A, Marston M, Kasamba I, Mushati P, Lutalo T, Hosegood V, Zaba Bet al., 2009, Reported number of sexual partners: comparison of data from four African longitudinal studies, SEXUALLY TRANSMITTED INFECTIONS, Vol: 85, Pages: I72-I80, ISSN: 1368-4973

Journal article

Wringe A, Cremin I, Todd J, McGrath N, Kasamba I, Herbst K, Mushore P, Zaba B, Slaymaker Eet al., 2009, Comparative assessment of the quality of age-at-event reporting in three HIV cohort studies in sub-Saharan Africa, SEXUALLY TRANSMITTED INFECTIONS, Vol: 85, Pages: I56-I63, ISSN: 1368-4973

Journal article

Marston M, Slaymaker E, Cremin I, Floyd S, McGrath N, Kasamba I, Lutalo T, Nyirenda M, Ndyanabo A, Mupambireyi Z, Zaba Bet al., 2009, Trends in marriage and time spent single in sub-Saharan Africa: a comparative analysis of six population-based cohort studies and nine Demographic and Health Surveys, SEXUALLY TRANSMITTED INFECTIONS, Vol: 85, Pages: I64-I71, ISSN: 1368-4973

Journal article

Cremin I, Mushati P, Hallett T, Mupambireyi Z, Nyamukapa C, Garnett GP, Gregson Set al., 2009, Measuring trends in age at first sex and age at marriage in Manicaland, Zimbabwe, SEXUALLY TRANSMITTED INFECTIONS, Vol: 85, Pages: I34-I40, ISSN: 1368-4973

Journal article

Hallett TB, Dube S, Cremin I, Lopman B, Mahomva A, Ncube G, Mugurungi O, Gregson S, Garnett GPet al., 2009, The role of testing and counselling for HIV prevention and care in the era of scaling-up antiretroviral therapy, Epidemics, Vol: 1, Pages: 77-82

Journal article

Sherr L, Lopman B, Kakowa M, Dube S, Chawira G, Nyamukapa C, Oberzaucher N, Cremin I, Gregson Set al., 2007, Voluntary counselling and testing: uptake, impact on sexual behaviour, and HIV incidence in a rural Zimbabwean cohort, AIDS, Vol: 21, Pages: 851-860, ISSN: 0269-9370

Journal article

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