Publications
81 results found
Baggaley RF, Owen BN, Silhol R, et al., 2018, Per Act HIV Transmission Risk Through Anal Intercourse: An Updated Systematic Review and Meta-analysis, HIV Research for Prevention Meeting (HIVR4P) - AIDS Vaccine, Microbicide and ARV-Based Prevention Science, Publisher: MARY ANN LIEBERT, INC, Pages: 391-391, ISSN: 0889-2229
Baggaley RF, Irvine MA, Leber W, et al., 2017, Cost-effectiveness of screening for HIV in primary care: a health economics modelling analysis, Lancet HIV, Vol: 4, Pages: E465-E474, ISSN: 2405-4704
BackgroundEarly HIV diagnosis reduces morbidity, mortality, the probability of onward transmission, and their associated costs, but might increase cost because of earlier initiation of antiretroviral treatment (ART). We investigated this trade-off by estimating the cost-effectiveness of HIV screening in primary care.MethodsWe modelled the effect of the four-times higher diagnosis rate observed in the intervention arm of the RHIVA2 randomised controlled trial done in Hackney, London (UK), a borough with high HIV prevalence (≥0·2% adult prevalence). We constructed a dynamic, compartmental model representing incidence of infection and the effect of screening for HIV in general practices in Hackney. We assessed cost-effectiveness of the RHIVA2 trial by fitting model diagnosis rates to the trial data, parameterising with epidemiological and behavioural data from the literature when required, using trial testing costs and projecting future costs of treatment.FindingsOver a 40 year time horizon, incremental cost-effectiveness ratios were £22 201 (95% credible interval 12 662–132 452) per quality-adjusted life-year (QALY) gained, £372 207 (268 162–1 903 385) per death averted, and £628 874 (434 902–4 740 724) per HIV transmission averted. Under this model scenario, with UK cost data, RHIVA2 would reach the upper National Institute for Health and Care Excellence cost-effectiveness threshold (about £30 000 per QALY gained) after 33 years. Scenarios using cost data from Canada (which indicate prolonged and even higher health-care costs for patients diagnosed late) suggest this threshold could be reached in as little as 13 years.InterpretationScreening for HIV in primary care has important public health benefits as well as clinical benefits. We predict it to be cost-effective in the UK in the medium term. However, this intervention might be cost-effective far sooner, and even cost-saving, in settings where long-term health-car
Owen B, Elmes J, Silhol R, et al., 2017, How common and frequent is heterosexual anal intercourse among South Africans? A systematic review and meta-analysis, Journal of International AIDS Society, Vol: 20, ISSN: 1758-2652
Background: HIV is transmitted more effectively during anal intercourse (AI) than vaginal intercourse (VI). However, patterns of heterosexual AI practice and its contribution to South Africa’s generalized epidemic remain unclear. We aimed to determine how common and frequent heterosexual AI is in South Africa.Methods: We searched for studies reporting the proportion practising heterosexual AI (prevalence) and/or the number of AI and unprotected AI (UAI) acts (frequency) in South Africa from 1990 to 2015. Stratified random-effects meta-analysis by subgroups was used to produce pooled estimates and assess the influence of participant and study characteristics on AI prevalence. We also estimated the fraction of all sex acts which were AI or UAI and compared condom use during VI and AI.Results: Of 41 included studies, 31 reported on AI prevalence and 14 on frequency, over various recall periods. AI prevalence was high across different recall periods for sexually active general-risk populations (e.g. lifetime = 18.4% [95%CI:9.4–27.5%], three-month = 20.3% [6.1–34.7%]), but tended to be even higher in higher-risk populations such as STI patients and female sex workers (e.g. lifetime = 23.2% [0.0–47.4%], recall period not stated = 40.1% [36.2–44.0%]). Prevalence was higher in studies using more confidential interview methods. Among general and higher-risk populations, 1.2–40.0% and 0.7–21.0% of all unprotected sex acts were UAI, respectively. AI acts were as likely to be condom protected as vaginal acts.Discussion: Reported heterosexual AI is common but variable among South Africans. Nationally and regionally representative sexual behaviour studies that use standardized recall periods and confidential interview methods, to aid comparison across studies and minimize reporting bias, are needed. Such data could be used to estimate the extent to which AI contributes to South Africa’s HIV epidemic.
Ruzafa JC, Merinopoulou E, Baggaley RF, et al., 2016, Patient population with multiple myeloma and transitions across different lines of therapy in the USA: an epidemiologic model, PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Vol: 25, Pages: 871-879, ISSN: 1053-8569
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- Citations: 22
Cavallaro FL, Duclos D, Baggaley RF, et al., 2016, Taking stock: protocol for evaluating a family planning supply chain intervention in Senegal, REPRODUCTIVE HEALTH, Vol: 13, ISSN: 1742-4755
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- Citations: 11
Campbell OMR, Benova L, MacLeod D, et al., 2016, Family planning, antenatal and delivery care: cross-sectional survey evidence on levels of coverage and inequalities by public and private sector in 57 low- and middle-income countries, TROPICAL MEDICINE & INTERNATIONAL HEALTH, Vol: 21, Pages: 486-503, ISSN: 1360-2276
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- Citations: 32
Medley GF, Turner HC, Baggaley RF, et al., 2016, The Role of More Sensitive Helminth Diagnostics in Mass Drug Administration Campaigns: Elimination and Health Impacts, ADVANCES IN PARASITOLOGY, VOL 94: MATHEMATICAL MODELS FOR NEGLECTED TROPICAL DISEASES: ESSENTIAL TOOLS FOR CONTROL AND ELIMINATION, PT B, Editors: Basanez, Anderson, Publisher: ELSEVIER ACADEMIC PRESS INC, Pages: 343-392
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- Citations: 24
Moraga P, Cano J, Baggaley RF, et al., 2015, Modelling the distribution and transmission intensity of lymphatic filariasis in sub-Saharan Africa prior to scaling up interventions: Integrated use of geostatistical and mathematical modelling, Parasites & Vectors, Vol: 8, ISSN: 1756-3305
Background: Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination. The ability to interrupt transmission is, partly, influenced by the underlying intensity of transmission and its geographical variation. This information can also help guide the design of targeted surveillance activities. The present study uses a combination of geostatistical and mathematical modelling to predict the prevalence and transmission intensity of LF prior to the implementation of large-scale control in sub-Saharan Africa. Methods: A systematic search of the literature was undertaken to identify surveys on the prevalence of Wuchereria bancrofti microfilaraemia (mf), based on blood smears, and on the prevalence of antigenaemia, based on the use of an immuno-chromatographic card test (ICT). Using a suite of environmental and demographic data, spatiotemporal multivariate models were fitted separately for mf prevalence and ICT-based prevalence within a Bayesian framework and used to make predictions for non-sampled areas. Maps of the dominant vector species of LF were also developed. The maps of predicted prevalence and vector distribution were linked to mathematical models of the transmission dynamics of LF to infer the intensity of transmission, quantified by the basic reproductive number (R0). Results: The literature search identified 1267 surveys that provide suitable data on the prevalence of mf and 2817 surveys that report the prevalence of antigenaemia. Distinct spatial predictions arose from the models for mf prevalence and ICT-based prevalence, with a wider geographical distribution when using ICT-based data. The vector distribution maps demonstrated the spatial variation of LF vector species. Mathematical modelling showed that the reproduction number (R0) estimates vary from 2.7 to 30, with large variations between and within regions. Conclusions: LF transmission is highly heterogeneous, and the developed maps can help guide intervention
Ruzafa JC, Merinopoulou E, Baggaley RF, et al., 2015, Patient Population with Multiple Myeloma and Transitions Across Different Lines of Therapy in the US: An Epidemiologic Model, Publisher: WILEY-BLACKWELL, Pages: 29-30, ISSN: 1053-8569
Baggaley RF, Hollingsworth TD, 2015, HIV-1 transmissions during asymptomatic infection: exploring the impact of changes in HIV-1 viral load due to coinfections, Jaids-Journal of Acquired Immune Deficiency Syndromes, Vol: 68, Pages: 594-598, ISSN: 1944-7884
Abstract: High HIV-1 plasma viral loads (PVLs) in sub-Saharan Africa, partly because of high rates of coinfection, may have been one of the drivers of the “explosive” epidemics seen in that region. Using a previously published framework of infectiousness and survival, we estimate the excess onward HIV-1 transmission events (secondary infections) resulting from coinfection-induced changes in PVL during asymptomatic HIV-1 infection. For every 100 HIV-infected people, each suffering 1 episode of tuberculosis infection, there are 4.9 (2.7th–97.5th percentile: 0.2–21.5) excess onward HIV-1 transmission events attributable to this coinfection. Other estimates are malaria 0.4 (0.0–2.0), soil-transmitted helminths 3.1 (0.1–14.9), schistosomiasis 8.5 (0.2–38.6), filariasis 13.3 (0.3–89.2), syphilis 0.1 (0.0–1.6), herpes simplex virus 4.0 (0.0–24.2), and gonorrhea 2.1 (0.1–8.0) transmissions. If these higher PVLs confer a shorter life expectancy and higher infectiousness, then their impact on transmission is, in general, reduced. For most HIV-1 coinfections, the duration of a single infection is too short and/or the associated PVL elevation is too modest to contribute substantially to onward HIV-1 transmission.
Lopez EL, Marta Contrini M, Mistchenko A, et al., 2015, Modeling the Long-term Persistence of Hepatitis A Antibody After a Two-Dose Vaccination Schedule in Argentinean Children, PEDIATRIC INFECTIOUS DISEASE JOURNAL, Vol: 34, Pages: 417-425, ISSN: 0891-3668
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- Citations: 18
Marsh K, Chapman R, Baggaley RF, et al., 2014, Mind the gaps: What's missing from current economic evaluations of universal HPV vaccination?, VACCINE, Vol: 32, Pages: 3732-3739, ISSN: 0264-410X
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- Citations: 14
Owen BN, Brock PM, Shubber Z, et al., 2013, 31. Lifetime prevalence of anal intercourse among sexually active female youth and young female sex workers: a comparative systematic review and meta-analysis., ISSN: 1448-5028
Background Anal cancer incidence has increased over the past twenty years. Heterosexual anal intercourse (AI) is a risk factor for HPV and HIV infection but is under-researched and ill-understood. We compare AI practices among young, sexually active general population females and female sex workers (FSW). Methods: We searched PubMed for heterosexual AI studies among young females, including FSWs (mean age <25 years), to December 2012. Study estimates were pooled using a random-effects model. Results: Fifty-four studies (42 average-risk, 6 higher-risk, 6 FSWs) were included. Most studies among general population youth were conducted in North America using self-administered questionnaires. All FSW studies were conducted in Africa and Asia using face-to-face interviews (FTFI). Pooled estimates of lifetime AI prevalence were larger among average-risk (23.6%, 95% CI 20.4-26.7) and higher-risk youth (25.5%, 95% CI 11.7-39.2) than FSWs (12.8%, 95% CI 8.4-17.3), but highly heterogeneous (I2 >90%). However, pooled AI estimates by continent of average-risk youth (Asia=13.9%, 95% CI=1.7-29.5; Africa=18.4%, 95% CI 0.9-35.8) were more similar to those of FSWs (Asia=16.0%, 95% CI 10.3-21.6; Africa=9.7%, 95% CI 3.8-15.7). Estimates of average-risk youth reporting via FTFI (12.1%, 95% CI 0.7-23.5) were likewise similar to those among FSWs (12.8%, 95% CI 8.4-17.3). Pooled AI prevalence estimates among FSWs were higher in studies conducted after 2001 than in earlier studies. Conclusions: AI is common among sexually active females and may be increasing; it could therefore be an important determinant of HPV transmission and anal cancers. AI is as or more common among the general population youth than young FSWs but this may be confounded by continent, interview method and other unmeasured variables.
Owen BN, Brock PM, Baggaley RF, et al., 2013, HETEROSEXUAL ANAL INTERCOURSE AMONG YOUTH: A SYSTEMATIC REVIEW AND METAANALYSIS, SEXUALLY TRANSMITTED INFECTIONS, Vol: 89, Pages: A148-A148, ISSN: 1368-4973
Baggaley RF, Dimitrov D, Owen BN, et al., 2013, Heterosexual Anal Intercourse: A Neglected Risk Factor for HIV?, AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Vol: 69, Pages: 95-105, ISSN: 1046-7408
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- Citations: 47
Owen BN, Brock PM, Shubber Z, et al., 2013, Lifetime prevalence of anal intercourse among sexually active female youth and young female sex workers: a comparative systematic review and meta-analysis, Publisher: CSIRO PUBLISHING, Pages: 585-585, ISSN: 1448-5028
Baggaley RF, White RG, Hollingsworth TD, et al., 2013, Heterosexual HIV-1 Infectiousness and Antiretroviral Use: Systematic Review of Prospective Studies of Discordant Couples., Epidemiology, Vol: 1, Pages: 110-121
BACKGROUND: : Recent studies have estimated the reduction in HIV-1 infectiousness with antiretroviral therapy (ART), but high-quality studies such as randomized controlled trials, accompanied by rigorous adherence counseling, are likely to overestimate the effectiveness of treatment-as-prevention in real-life settings.METHODS: : We attempted to summarize the effect of ART on HIV transmission by undertaking a systematic review and meta-analysis of HIV-1 infectiousness per heterosexual partnership (incidence rate and cumulative incidence over study follow-up) estimated from prospective studies of discordant couples. We used random-effects Poisson regression models to obtain summary estimates. When possible, the analyses were further stratified by direction of transmission (man-to-woman or woman-to-man) and economic setting (high- or low-income countries). Potential causes of heterogeneity of estimates were explored through subgroup analyses.RESULTS: : Fifty publications were included. Nine allowed comparison between ART and non-ART users within studies (ART-stratified studies), in which summary incidence rates were 3.6/100 person-years (95% confidence interval = 2.0-6.5) and 0.2/100 person-years (0.07-0.7) for non-ART- and ART-using couples, respectively (P < 0.001), constituting a 91% (79-96%) reduction in per-partner HIV-1 incidence rate with ART use. The 41 studies that did not stratify by ART use provided estimates with high levels of heterogeneity (I statistic) and few reported levels of ART use, making interpretation difficult. Nevertheless, estimates tended to be lower with ART use. Infectiousness tended to be higher for low-income than high-income settings, but there was no clear pattern by direction of transmission (man-to-woman and woman-to-man).CONCLUSIONS: : ART substantially reduces HIV-1 infectiousness within discordant couples, based on observational studies, and could play a major part in HIV-1 prevention efforts. However, the non-zero risk from par
Owen BN, Brock PM, Baggaley RF, et al., 2012, Prevalence of heterosexual anal intercourse among youth: a systematic review and meta-analysis, 28th International Papillomavirus Conference
Boily M-C, Alary M, Baggaley RF, 2012, Neglected Issues and Hypotheses Regarding the Impact of Sexual Concurrency on HIV and Sexually Transmitted Infections, AIDS AND BEHAVIOR, Vol: 16, Pages: 304-311, ISSN: 1090-7165
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- Citations: 23
Dimitrov DT, Boily M-C, Baggaley RF, et al., 2011, Modeling the gender-specific impact of vaginal microbicides on HIV transmission, JOURNAL OF THEORETICAL BIOLOGY, Vol: 288, Pages: 9-20, ISSN: 0022-5193
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- Citations: 14
Baggaley RF, Powers KA, Boily M-C, 2011, What do mathematical models tell us about the emergence and spread of drug-resistant HIV?, CURRENT OPINION IN HIV AND AIDS, Vol: 6, Pages: 131-140, ISSN: 1746-630X
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- Citations: 12
Brown T, Bao L, Raftery AE, et al., 2010, Modelling HIV epidemics in the antiretroviral era: the UNAIDS Estimation and Projection package 2009, SEXUALLY TRANSMITTED INFECTIONS, Vol: 86, Pages: I3-I10, ISSN: 1368-4973
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- Citations: 63
Baggaley RF, Burgin J, Campbell OMR, 2010, The Potential of Medical Abortion to Reduce Maternal Mortality in Africa: What Benefits for Tanzania and Ethiopia?, PLOS ONE, Vol: 5, ISSN: 1932-6203
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- Citations: 12
Baggaley RF, White RG, Boily M-C, 2010, Infectiousness of HIV-infected homosexual men in the era of highly active antiretroviral therapy, AIDS, Vol: 24, Pages: 2418-2420, ISSN: 0269-9370
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- Citations: 14
Baggaley RF, Fraser C, 2010, Modelling sexual transmission of HIV: testing the assumptions, validating the predictions, CURRENT OPINION IN HIV AND AIDS, Vol: 5, Pages: 269-276, ISSN: 1746-630X
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- Citations: 23
Baggaley RF, White RG, Boily M-C, 2010, HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention, International Journal of Epidemiology, Vol: 39, Pages: 1048-1063, ISSN: 1464-3685
Background The human immunodeficiency virus (HIV) infectiousness of anal intercourse (AI) has not been systematically reviewed, despite its role driving HIV epidemics among men who have sex with men (MSM) and its potential contribution to heterosexual spread. We assessed the per-act and per-partner HIV transmission risk from AI exposure for heterosexuals and MSM and its implications for HIV prevention.Methods Systematic review and meta-analysis of the literature on HIV-1 infectiousness through AI was conducted. PubMed was searched to September 2008. A binomial model explored the individual risk of HIV infection with and without highly active antiretroviral therapy (HAART).Results A total of 62 643 titles were searched; four publications reporting per-act and 12 reporting per-partner transmission estimates were included. Overall, random effects model summary estimates were 1.4% [95% confidence interval (CI) 0.2–2.5)] and 40.4% (95% CI 6.0–74.9) for per-act and per-partner unprotected receptive AI (URAI), respectively. There was no significant difference between per-act risks of URAI for heterosexuals and MSM. Per-partner unprotected insertive AI (UIAI) and combined URAI–UIAI risk were 21.7% (95% CI 0.2–43.3) and 39.9% (95% CI 22.5–57.4), respectively, with no available per-act estimates. Per-partner combined URAI–UIAI summary estimates, which adjusted for additional exposures other than AI with a ‘main’ partner [7.9% (95% CI 1.2–14.5)], were lower than crude (unadjusted) estimates [48.1% (95% CI 35.3–60.8)]. Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time. AI may substantially increase HIV transmission risk even if the infected partner is receiving HAART; however, predictions are highly sens
Baggaley RF, Petersen ML, Soares MA, et al., 2010, Human Immunodeficiency Virus: Resistance to Antiretroviral Drugs in Developing Countries, ANTIMICROBIAL RESISTANCE IN DEVELOPING COUNTRIES, Editors: Sosa, Byarugaba, AmabileCuevas, Hsueh, Kariuki, Okeke, Publisher: SPRINGER, Pages: 75-94, ISBN: 978-0-387-89369-3
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- Citations: 4
Ganaba R, Marshall T, Sombie I, et al., 2010, Women's sexual health and contraceptive needs after a severe obstetric complication ("near-miss"): a cohort study in Burkina Faso, REPRODUCTIVE HEALTH, Vol: 7
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- Citations: 21
Boily MC, Buvé A, Baggaley RF, 2010, HIV transmission in serodiscordant heterosexual couples., BMJ, Vol: 340
Boily M-C, Baggaley RF, Masse B, 2009, The role of heterosexual anal intercourse for HIV transmission in developing countries: are we ready to draw conclusions?, SEXUALLY TRANSMITTED INFECTIONS, Vol: 85, Pages: 408-410, ISSN: 1368-4973
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- Citations: 19
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