21 results found
Vesga JF, Métras R, Clark MHA, et al., 2022, Vaccine efficacy trials for Crimean-Congo haemorrhagic fever: insights from modelling different epidemiological settings, Vaccine, Vol: 40, Pages: 5806-5813, ISSN: 0264-410X
BackgroundCrimean-Congo haemorrhagic fever (CCHF) is a priority emerging pathogen for which a licensed vaccine is not yet available. We aim to assess the feasibility of conducting phase III vaccine efficacy trials and the role of varying transmission dynamics.MethodsWe calibrate models of CCHF virus (CCHFV) transmission among livestock and spillover to humans in endemic areas in Afghanistan, Turkey and South Africa. We propose an individual randomised controlled trial targeted to high-risk population, and use the calibrated models to simulate trial cohorts to estimate the minimum necessary number of cases (trial endpoints) to analyse a vaccine with a minimum efficacy of 60%, under different conditions of sample size and follow-up time in the three selected settings.ResultsA mean follow-up of 160,000 person-month (75,000–550,000) would be necessary to accrue the required 150 trial endpoints for a target vaccine efficacy of 60 % and clinically defined endpoint, in a setting like Herat, Afghanistan. For Turkey, the same would be achieved with a mean follow-up of 175,000 person-month (50,000–350,000). The results suggest that for South Africa the low endemic transmission levels will not permit achieving the necessary conditions for conducting this trial within a realistic follow-up time. In the scenario of CCHFV vaccine trial designed to capture infection as opposed to clinical case as a trial endpoint, the required person-months is reduced by 70 % to 80 % in Afghanistan and Turkey, and in South Africa, a trial becomes feasible for a large number of person-months of follow-up (>600,000). Increased expected vaccine efficacy > 60 % will reduce the required number of trial endpoints and thus the sample size and follow-time in phase III trials.ConclusionsUnderlying endemic transmission levels will play a central role in defining the feasibility of phase III vaccine efficacy trials. Endemic settings in Afghanistan and Turkey offer conditions under which suc
Nsengiyumva NP, Campbell JR, Oxlade O, et al., 2022, Scaling up target regimens for tuberculosis preventive treatment in Brazil and South Africa: an analysis of costs and cost-effectiveness, PLoS Medicine, Vol: 19, ISSN: 1549-1277
BackgroundShorter, safer, and cheaper tuberculosis (TB) preventive treatment (TPT) regimens will enhance uptake and effectiveness. WHO developed target product profiles describing minimum requirements and optimal targets for key attributes of novel TPT regimens. We performed a cost-effectiveness analysis addressing the scale-up of regimens meeting these criteria in Brazil, a setting with relatively low transmission and low HIV and rifampicin-resistant TB (RR-TB) prevalence, and South Africa, a setting with higher transmission and higher HIV and RR-TB prevalence.Methods and findingsWe used outputs from a model simulating scale-up of TPT regimens meeting minimal and optimal criteria. We assumed that drug costs for minimal and optimal regimens were identical to 6 months of daily isoniazid (6H). The minimal regimen lasted 3 months, with 70% completion and 80% efficacy; the optimal regimen lasted 1 month, with 90% completion and 100% efficacy. Target groups were people living with HIV (PLHIV) on antiretroviral treatment and household contacts (HHCs) of identified TB patients. The status quo was 6H at 2019 coverage levels for PLHIV and HHCs. We projected TB cases and deaths, TB-associated disability-adjusted life years (DALYs), and costs (in 2020 US dollars) associated with TB from a TB services perspective from 2020 to 2035, with 3% annual discounting. We estimated the expected costs and outcomes of scaling up 6H, the minimal TPT regimen, or the optimal TPT regimen to reach all eligible PLHIV and HHCs by 2023, compared to the status quo. Maintaining current 6H coverage in Brazil (0% of HHCs and 30% of PLHIV treated) would be associated with 1.1 (95% uncertainty range [UR] 1.1–1.2) million TB cases, 123,000 (115,000–132,000) deaths, and 2.5 (2.1–3.1) million DALYs and would cost $1.1 ($1.0–$1.3) billion during 2020–2035. Expanding the 6H, minimal, or optimal regimen to 100% coverage among eligible groups would reduce DALYs by 0.5% (95% UR 1.2
Vesga J, Lienhardt C, Nsengimyumva P, et al., 2022, Prioritising attributes for tuberculosis preventive treatment regimens: a modelling analysis, BMC Medicine, Vol: 20, ISSN: 1741-7015
Background:Recent years have seen important improvements in available preventive treatment regimens for tuberculosis (TB), and research is ongoing to develop these further. To assist with the formulation of target product profiles for future regimens, we examined which regimen properties would be most influential in the epidemiological impact of preventive treatment.Methods:Following expert consultation, we identified 5 regimen properties relevant to the incidence-reducing impact of a future preventive treatment regimen: regimen duration, efficacy, ease-of-adherence (treatment completion rates in programmatic conditions), forgiveness to non-completion and the barrier to developing rifampicin resistance during treatment. For each regimen property, we elicited expert input for minimally acceptable and optimal (ideal-but-feasible) performance scenarios for future regimens. Using mathematical modelling, we then examined how each regimen property would influence the TB incidence reduction arising from full uptake of future regimens according to current WHO guidelines, in four countries: South Africa, Kenya, India and Brazil.Results:Of all regimen properties, efficacy is the single most important predictor of epidemiological impact, while ease-of-adherence plays an important secondary role. These results are qualitatively consistent across country settings; sensitivity analyses show that these results are also qualitatively robust to a range of model assumptions, including the mechanism of action of future preventive regimens.Conclusions:As preventive treatment regimens against TB continue to improve, understanding the key drivers of epidemiological impact can assist in guiding further development. By meeting these key targets, future preventive treatment regimens could play a critical role in global efforts to end TB.
Vesga JF, Clark MHA, Ayazi E, et al., 2022, Transmission dynamics and vaccination strategies for Crimean-Congo haemorrhagic fever virus in Afghanistan: a modelling study, PLoS Neglected Tropical Diseases, Vol: 16, Pages: 1-17, ISSN: 1935-2727
BACKGROUND: Crimean-Congo haemorrhagic fever virus (CCHFV) is a highly pathogenic virus for which a safe and effective vaccine is not yet available, despite being considered a priority emerging pathogen. Understanding transmission patterns and the use of potential effective vaccines are central elements of the future plan against this infection. METHODS: We developed a series of models of transmission amongst livestock, and spillover infection into humans. We use real-world human and animal data from a CCHFV endemic area in Afghanistan (Herat) to calibrate our models. We assess the value of environmental drivers as proxy indicators of vector activity, and select the best model using deviance information criteria. Finally we assess the impact of vaccination by simulating campaigns targeted to humans or livestock, and to high-risk subpopulations (i.e, farmers). FINDINGS: Saturation deficit is the indicator that better explains tick activity trends in Herat. Recent increments in reported CCHFV cases in this area are more likely explained by increased surveillance capacity instead of changes in the background transmission dynamics. Modelling suggests that clinical cases only represent 31% (95% CrI 28%-33%) of total infections in this area. Vaccination campaigns targeting humans would result in a much larger impact than livestock vaccination (266 vs 31 clinical cases averted respectively) and a more efficient option when assessed in courses per case averted (35 vs 431 respectively). Targeted vaccination of farmers is impactful and more efficient, resulting in 19 courses per case averted (95% CrI 7-62) compared to targeting the general population (35 courses 95% CrI 16-107). CONCLUSIONS: CCHFV is endemic in Herat, and transmission cycles are well predicted by environmental drivers like saturation deficit. Vaccinating humans is likely to be more efficient and impactful than animals, and importantly targeted interventions to high risk groups like farmers can offer a more ef
Cilloni L, Fu H, Vesga JF, et al., 2020, The potential impact of the COVID-19 pandemic on the tuberculosis epidemic a modelling analysis, EClinicalMedicine, Vol: 28, ISSN: 2589-5370
Background: Routine services for tuberculosis (TB) are being disrupted by stringent lockdowns against the novel SARS-CoV-2 virus. We sought to estimate the potential long-term epidemiological impact of such disruptions on TB burden in high-burden countries, and how this negative impact could be mitigated. Methods: We adapted mathematical models of TB transmission in three high-burden countries (India, Kenya and Ukraine) to incorporate lockdown-associated disruptions in the TB care cascade. The anticipated level of disruption reflected consensus from a rapid expert consultation. We modelled the impact of these disruptions on TB incidence and mortality over the next five years, and also considered potential interventions to curtail this impact. Findings: Even temporary disruptions can cause long-term increases in TB incidence and mortality. If lockdown-related disruptions cause a temporary 50% reduction in TB transmission, we estimated that a 3-month suspension of TB services, followed by 10 months to restore to normal, would cause, over the next 5 years, an additional 1⋅19 million TB cases (Crl 1⋅06-1⋅33) and 361,000 TB deaths (CrI 333-394 thousand) in India, 24,700 (16,100-44,700) TB cases and 12,500 deaths (8.8-17.8 thousand) in Kenya, and 4,350 (826-6,540) cases and 1,340 deaths (815-1,980) in Ukraine. The principal driver of these adverse impacts is the accumulation of undetected TB during a lockdown. We demonstrate how long term increases in TB burden could be averted in the short term through supplementary "catch-up" TB case detection and treatment, once restrictions are eased. Interpretation: Lockdown-related disruptions can cause long-lasting increases in TB burden, but these negative effects can be mitigated with rapid restoration of TB services, and targeted interventions that are implemented as soon as restrictions are lifted. Funding: USAID and Stop TB Partnership.
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, Pages: e1132-e1141, ISSN: 2214-109X
Background: COVID-19 has the potential to cause substantial disruptions to health services, including by cases overburdening the health system or response measures limiting usual programmatic activities. We aimed to quantify the extent to which disruptions in services for human immunodeficiency virus (HIV), tuberculosis (TB) and malaria in low- and middle-income countries with high burdens of those disease could lead to additional loss of life. Methods: We constructed plausible scenarios for the disruptions that could be incurred during the COVID-19 pandemic and used established transmission models for each disease to estimate the additional impact on health that could be caused in selected settings.Findings: In high burden settings, HIV-, TB- and malaria-related deaths over five years may increase by up to 10%, 20% and 36%, respectively, compared to if there were no COVID-19 pandemic. We estimate the greatest impact on HIV to be from interruption to antiretroviral therapy, which may occur during a period of high health system demand. For TB, we estimate the greatest impact is from reductions in timely diagnosis and treatment of new cases, which may result from any prolonged period of COVID-19 suppression interventions. We estimate that the greatest impact on malaria burden could come from interruption of planned net campaigns. These disruptions could lead to loss of life-years over five years that is of the same order of magnitude as the direct impact from COVID-19 in places with a high burden of malaria and large HIV/TB epidemics.Interpretation: Maintaining the most critical prevention activities and healthcare services for HIV, TB and malaria could significantly reduce the overall impact of the COVID-19 pandemic.Funding: Bill & Melinda Gates Foundation, The Wellcome Trust, DFID, MRC
Vesga JF, Arinaminpathy N, 2019, Modelling tuberculosis control priorities: more of the same will not do, LANCET GLOBAL HEALTH, Vol: 7, Pages: E1320-E1320, ISSN: 2214-109X
Mangal TD, Pascom ARP, Vesga JF, et al., 2019, Estimating HIV incidence from surveillance data indicates a second wave of infections in Brazil, Epidemics, Vol: 27, Pages: 77-85, ISSN: 1755-4365
Emerging evidence suggests that HIV incidence rates in Brazil, particularly among men, may be rising. Here we use Brazil’s integrated health systems data to develop a mathematical model, reproducing the complex surveillance systems and providing estimates of HIV incidence, number of people living with HIV (PLHIV), reporting rates and ART initiation rates.An age-structured deterministic model with a flexible spline was used to describe the natural history of HIV along with reporting and treatment rates. Individual-level surveillance data for 1,077,295 cases (HIV/AIDS diagnoses, ART dispensations, CD4 counts and HIV/AIDS-related deaths) were used to calibrate the model using Bayesian inference.The results showed a second wave of infections occurring after 2001 and 56,000 (95% Credible Interval 43,000–71,000) new infections in 2015, 37,000 (95% CrI 28,000–54,000) infections in men and 16,000 (95% CrI 10,000–23,000) in women. The estimated number of PLHIV by end-2015 was 838,000 (95% CrI 675,000–1,083,000), with 80% (95% CrI 62–98%) of those individuals reported to the Ministry of Health. Women were more likely to be diagnosed and reported than men; 86.8% of infected women had been reported compared with 75.7% of men. Likewise, ART initiation rates for women were higher than those for men.The second wave contradicts previous estimates of HIV incidence trends in Brazil and there were persistent differences in the rates of accessing care between men and women. Nevertheless, the Brazilian HIV program has achieved high rates of detection and treatment, making considerable progress over the past ten years.
Vesga JF, Hallett TB, Reid MJA, et al., 2019, Assessing tuberculosis control priorities in high-burden settings: a modelling approach, The Lancet Global Health, Vol: 7, Pages: e585-e595, ISSN: 2214-109X
Background:In the context of WHO's End TB strategy, there is a need to focus future control efforts on those interventions and innovations that would be most effective in accelerating declines in tuberculosis burden. Using a modelling approach to link the tuberculosis care cascade to transmission, we aimed to identify which improvements in the cascade would yield the greatest effect on incidence and mortality.Methods:We engaged with national tuberculosis programmes in three country settings (India, Kenya, and Moldova) as illustrative examples of settings with a large private sector (India), a high HIV burden (Kenya), and a high burden of multidrug resistance (Moldova). We collated WHO country burden estimates, routine surveillance data, and tuberculosis prevalence surveys from 2011 (for India) and 2016 (for Kenya). Linking the tuberculosis care cascade to tuberculosis transmission using a mathematical model with Bayesian melding in each setting, we examined which cascade shortfalls would have the greatest effect on incidence and mortality, and how the cascade could be used to monitor future control efforts.Findings:Modelling suggests that combined measures to strengthen the care cascade could reduce cumulative tuberculosis incidence by 38% (95% Bayesian credible intervals 27–43) in India, 31% (25–41) in Kenya, and 27% (17–41) in Moldova between 2018 and 2035. For both incidence and mortality, modelling suggests that the most important cascade losses are the proportion of patients visiting the private health-care sector in India, missed diagnosis in health-care settings in Kenya, and drug sensitivity testing in Moldova. In all settings, the most influential delay is the interval before a patient's first presentation for care. In future interventions, the proportion of individuals with tuberculosis who are on high-quality treatment could offer a more robust monitoring tool than routine notifications of tuberculosis.Interpretation:Linked to transmissi
Maheu-Giroux M, Diabate S, Boily M-C, et al., 2019, Cost-effectiveness of accelerated HIV response scenarios in Côte d’Ivoire, JAIDS-Journal of Acquired Immune Deficiency Syndromes, Vol: 80, Pages: 503-512, ISSN: 1525-4135
Background: Despite Côte d’Ivoire epidemic being labelled as ‘generalized’, key populations (KP) are important to overall transmission. Using a dynamic model of HIV transmission, we previously estimated the impact of several treatment-as-prevention strategies that reached –or missed– the UNAIDS 90-90-90 targets in different populations groups, including KP and clients of female sex workers (CFSW). To inform program planning and resources allocation, we assessed the cost-effectiveness of these scenarios.Methods: Costing was performed from the provider’s perspective. Unit costs were obtained from the Ivorian Programme national de lutte contre le Sida (USD 2015) and discounted at 3%. Net incremental cost-effectiveness ratios (ICER) per adult HIV infection prevented and per disability-adjusted life years (DALY) averted were estimated over 2015-2030.Results: The three most cost-effective and affordable scenarios were the ones that projected current programmatic trends (ICER=$210; 90% uncertainty interval [90UI%]: $150-$300), attaining the 90-90-90 objectives among KP and CFSW (ICER=$220; 90%UI: $80-$510), and among KP only (ICER=$290; 90%UI: $90-$660). The least cost-effective scenario was the one that reached the UNAIDS 90-90-90 target accompanied by a 25% point drop in condom use in KP (ICER=$710; 90%UI: $450-$1,270). In comparison, the UNAIDS scenario had a net ICER of $570 (90%UI: $390-$900) per DALY averted.Conclusions: According to commonly used thresholds, accelerating the HIV response can be considered very cost-effective for all scenarios. However, when balancing epidemiological impact, cost-effectiveness, and affordability, scenarios that sustain both high condom use and rates of viral suppression among KP and CFSW appear most promising in Côte d’Ivoire.
Reid MJA, Arinaminpathy N, Bloom A, et al., 2019, Building a tuberculosis-free world: The Lancet Commission on tuberculosis, The Lancet, Vol: 393, Pages: 1331-1384, ISSN: 0140-6736
Maheu-Giroux M, Vesga J, Diabate S, et al., 2017, Population-level impact of an accelerated HIV response plan to reach the UNAIDS 90-90-90 target in Côte d’Ivoire: Insights from mathematical modeling, PLoS Medicine, Vol: 14, ISSN: 1549-1277
Background:National responses will need to be markedly accelerated to achieve the ambitious target of the Joint United Nations Programme on HIV/AIDS (UNAIDS). This target aims for 90% of HIV-positive individuals to be aware of their status, for 90% of those aware to receive antiretroviral therapy (ART), and for 90% of those on treatment to have a suppressed viral load by 2020, with each individual target reaching 95% by 2030. We aimed to estimate the impact of various treatment-as-prevention scenarios in Côte d’Ivoire, one of the countries with the highest HIV incidence in West Africa, with unmet HIV prevention and treatment needs, and where key populations are important to the broader HIV epidemic.Methods and findings:An age-stratified dynamic model was developed and calibrated to epidemiological and programmatic data using a Bayesian framework. The model represents sexual and vertical HIV transmission in the general population, female sex workers (FSW), and men who have sex with men (MSM). We estimated the impact of scaling up interventions to reach the UNAIDS targets, as well as the impact of 8 other scenarios, on HIV transmission in adults and children, compared to our baseline scenario that maintains 2015 rates of testing, ART initiation, ART discontinuation, treatment failure, and levels of condom use. In 2015, we estimated that 52% (95% credible intervals: 46%–58%) of HIV-positive individuals were aware of their status, 72% (57%–82%) of those aware were on ART, and 77% (74%–79%) of those on ART were virologically suppressed. Reaching the UNAIDS targets on time would avert 50% (42%–60%) of new HIV infections over 2015–2030 compared to 30% (25%–36%) if the 90-90-90 target is reached in 2025. Attaining the UNAIDS targets in FSW, their clients, and MSM (but not in the rest of the population) would avert a similar fraction of new infections (30%; 21%–39%). A 25-percentage-point drop in condom use from the 2015
Maheu-Giroux M, Baral S, Vesga JF, et al., 2017, Anal intercourse among female sex workers in Côte d’Ivoire: prevalence,determinants, and model-based estimates of the population-level impact onHIV transmission, American Journal of Epidemiology, Vol: 187, Pages: 287-297, ISSN: 1476-6256
urrent evidence suggests that anal intercourse (AI) during sex work is common in sub-Saharan Africa, but few studies investigated the contribution of heterosexual AI to HIV epidemics. Using a respondent-driven sampling survey of female sex workers (FSW) in Abidjan (2014), we estimated AI prevalence and frequency. Poisson regressions were used to identify AI determinants. About 20% of FSW (N = 466) engaged in AI during a normal week (95% confidence intervals: 15-26%). Women who performed AI were generally younger, had been selling sex for longer, were born in Côte d'Ivoire, reported higher sex-work income, more frequent sex in public places, and violence from clients than women not reporting AI. Condom use was lower, condom breakage/slippage more frequent, and use of water-based lubricants was less frequently reported for AI than for vaginal intercourse. Using a dynamic transmission model, we estimated that 22% (95% credible intervals: 11-37%) of new HIV infections could have been averted among FSW during 2000-2015 if AI had been substituted for vaginal intercourse acts. Despite representing a small fraction of all sex acts, AI is an underestimated source of HIV transmission. Increasing availability/uptake of condoms, lubricants, and pre-exposure prophylaxis for women engaging in AI could help mitigate HIV risk.
Maheu-Giroux M, Vesga JF, Diabate S, et al., 2017, Changing dynamics of HIV transmission in Côte d'Ivoire: modeling which key populations acquired and transmitted infections and estimating the impact of past HIV interventions (1976-2015), JAIDS - Journal of Acquired Immune Deficiency Syndromes, Vol: 75, Pages: 517-527, ISSN: 1525-4135
Introduction: Understanding the impact of past interventions and how it affected transmission dynamics is key to guiding prevention efforts. We estimated the population-level impact of condom, antiretroviral therapy (ART), and prevention of mother-to-child transmission activities on HIV transmission and the contribution of key risk factors on HIV acquisition and transmission. Methods: An age stratified dynamical model of sexual and vertical HIV transmission among the general population, female sex workers (FSW), and men who have sex with men (MSM) was calibrated to detailed prevalence and intervention data. We estimated the fraction of HIV infections averted by the interventions, and the fraction of incident infections acquired and transmitted by different populations over successive 10-year periods (1976-2015). Results: Overall, condom use averted 61% (95% Credible Intervals: 56-66%) of all adult infections during 1987-2015 mainly due to increases by FSW (46% of infections averted). In comparison, ART prevented 15% (10-19%) of adult infections during 2010- 2015. As a result, FSW initially (1976-1985) contributed 95% (91-97%) of all new infections, declining to 19% (11-27%) during 2005-2015. Older men and clients mixing with non-FSW are currently the highest contributor to transmission. MSM contributed ≤4% transmissions throughout. Young women (15-24 years; excluding FSW) do not transmit more infection than they acquired. Conclusion: Early increases in condom use, mainly by FSW, have substantially reduced HIV transmission. Clients of FSW and older men have become the main source of transmission whereas young women remain at increased risk. Strengthening prevention and scaling-up of ART, particularly to FSW and CFSW, is important.
Vesga JF, Cori A, van Sighem A, et al., 2014, Estimating HIV incidence from case-report data: method and an application in Colombia, AIDS, Vol: 28, Pages: S489-S496, ISSN: 0269-9370
Shubber Z, Mishra S, Vesga JF, et al., 2014, The HIV Modes of Transmission model: a systematic review of its findings and adherence to guidelines, Journal of the International AIDS Society, Vol: 17, ISSN: 1758-2652
Introduction: The HIV Modes of Transmission (MOT) model estimates the annual fraction of new HIV infections (FNI) acquired by different risk groups. It was designed to guide country-specific HIV prevention policies. To determine if the MOT produced context-specific recommendations, we analyzed MOT results by region and epidemic type, and explored the factors (e.g. data used to estimate parameter inputs, adherence to guidelines) influencing the differences.Methods: We systematically searched MEDLINE, EMBASE and UNAIDS reports, and contacted UNAIDS country directors for published MOT results from MOT inception (2003) to 25 September 2012.Results: We retrieved four journal articles and 20 UNAIDS reports covering 29 countries. In 13 countries, the largest FNI (range 26 to 63%) was acquired by the low-risk group and increased with low-risk population size. The FNI among female sex workers (FSWs) remained low (median 1.3%, range 0.04 to 14.4%), with little variability by region and epidemic type despite variability in sexual behaviour. In India and Thailand, where FSWs play an important role in transmission, the FNI among FSWs was 2 and 4%, respectively. In contrast, the FNI among men who have sex with men (MSM) varied across regions (range 0.1 to 89%) and increased with MSM population size. The FNI among people who inject drugs (PWID, range 0 to 82%) was largest in early-phase epidemics with low overall HIV prevalence. Most MOT studies were conducted and reported as per guidelines but data quality remains an issue.Conclusions: Although countries are generally performing the MOT as per guidelines, there is little variation in the FNI (except among MSM and PWID) by region and epidemic type. Homogeneity in MOT FNI for FSWs, clients and low-risk groups may limit the utility of MOT for guiding country-specific interventions in heterosexual HIV epidemics.
Boily M-C, Masse B, Alsallaq R, et al., 2012, HIV Treatment as Prevention: Considerations in the Design, Conduct, and Analysis of Cluster Randomized Controlled Trials of Combination HIV Prevention, PLOS Medicine, Vol: 9, ISSN: 1549-1277
HIV Modelling Consortium Treatment as Prevention Editorial Writing Group, 2012, HIV treatment as prevention: models, data, and questions--towards evidence-based decision-making., PLOS Medicine, Vol: 9, ISSN: 1549-1277
Antiretroviral therapy (ART) for those infected with HIV can prevent onward transmission of infection, but biological efficacy alone is not enough to guide policy decisions about the role of ART in reducing HIV incidence. Epidemiology, economics, demography, statistics, biology, and mathematical modelling will be central in framing key decisions in the optimal use of ART. PLoS Medicine, with the HIV Modelling Consortium, has commissioned a set of articles that examine different aspects of HIV treatment as prevention with a forward-looking research agenda. Interlocking themes across these articles are discussed in this introduction. We hope that this article, and others in the collection, will provide a foundation upon which greater collaborations between disciplines will be formed, and will afford deeper insights into the key factors involved, to help strengthen the support for evidence-based decision-making in HIV prevention.
Hidalgo M, Miranda J, Heredia D, et al., 2011, Outbreak of Rocky Mountain spotted fever in Córdoba, Colombia., Mem Inst Oswaldo Cruz, Vol: 106, Pages: 117-118
Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by the obligate intracellular bacterium Rickettsia rickettsii. Although RMSF was first reported in Colombia in 1937, it remains a neglected disease. Herein, we describe the investigation of a large cluster of cases of spotted fever rickettsiosis in a new area of Colombia.
Hidalgo M, Lizarazo D, Valbuena G, et al., 2009, A Survey of Antibodies against Rickettsia rickettsii and Ehrlichia chafeensis in Domestic Animals from a Rural Area of Colombia, The American Journal of Tropical Medicine and Hygiene, Vol: 80, Pages: 1029-1030, ISSN: 0002-9637
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