Juan Vesga

London School of Hygiene and Tropical Medicine | LSHTM · Centre for the Mathematical Modelling of Infectious Diseases

Ixodes ricinus is the primary vector for Lyme disease and tick-borne encephalitis across Europe. To better understand the environmental and ecological drivers of its population dynamics, we collected monthly tick density data over ten years (2013-2022) in four sites in Northeast France, where I. ricinus has established, and developed and fitted a m...

Background: Closing the tuberculosis diagnostic gap and scaling-up tuberculosis preventive treatment (TPT) are two major global priorities to end the tuberculosis epidemic. To help support these efforts, we modeled the impact and return-on-investment (ROI) of a comprehensive intervention to improve tuberculosis screening and prevention in Brazil, G...

Background Crimean-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. Methods We calibrate models of CCHF virus (CCHFV) transmission among livestock and spil...

Background Crimean-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. Methods We calibrate models of CCHF virus (CCHFV) transmission among livestock and spil...

Background Shorter, 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...

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. Me...

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 pr...

Background The WHO has developed target product profiles (TPPs) describing the most appropriate qualities for future TPT regimens to assist developers in aligning the characteristics of new treatments with programmatic requirements. Methods A technical consultation group was convened by the WHO to determine regimen attributes with greatest potenti...

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. Me...

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...

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 T...

Background COVID-19 has the potential to cause substantial disruptions to health services, due to cases overburdening the health system or response measures limiting usual programmatic activities. We aimed to quantify the extent to which disruptions to services for HIV, tuberculosis, and malaria in low-income and middle-income countries with high b...

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...

Brazil is an epicentre for COVID-19 in Latin America. In this report we describe the Brazilian epidemic using three epidemiological measures: the number of infections, the number of deaths and the reproduction number. Our modelling framework requires sufficient death data to estimate trends, and we therefore limit our analysis to 16 states that hav...

COVID-19 has the potential to cause disruptions to health services in different ways; through the health system becoming overwhelmed with COVID-19 patients, through the intervention used to slow transmission of COVID-19 inhibiting access to preventative interventions and services, and through supplies of medicine being interrupted. We aim to quanti...

Background: Despite Côte d'Ivoire epidemic being labeled as "generalized," key populations (KPs) 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, includ...

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 casc...

Executive summary Tuberculosis can be treated, prevented, and cured. Rapid, sustained declines in tuberculosis deaths in many countries during the past 50 years provide compelling evidence that ending the pandemic is feasible. Yet this disease—which has plagued humanity since before recorded history and has killed hundreds of millions of people ove...

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...

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 s...

This file contains the tables of parameters, additional results, and the sensitivity analyses. (DOCX)

Résumé en français (French translation of the abstract). (DOCX)

Current 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 i...

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...

To estimate the incidence of HIV in the adult population of Paraguay for 2014 and analyze its distribution and associated uncertainty according to risk behavior. METHODS The UNAIDS model was applied according to modes of transmission (MoT). Data were obtained from a detailed review of documents prepared between 1996 and 2013. Uncertainty of the est...

OBJETIVO: Estimar la incidencia del VIH en la población adulta del Paraguay para 2014, y analizar su distribución con la incertidumbre asociada según comportamiento de riesgo. MÉTODOS: Se aplicó el modelo de ONUSIDA según modos de transmisión (MoT). Los datos se obtuvieron de la revisión detallada de documentos elaborados entre 1996 y 2013. Se real...

Objective: Quantifying HIV incidence is essential for tracking epidemics but doing this in concentrated epidemic can be a particular challenge because of limited consistent high-quality data about the size, behaviour and prevalence of HIV among key populations. Here, we examine a method for estimating HIV incidence from routinely collected case-rep...

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 th...

Background The HIV epidemic in Bogota, Colombia is mainly driven by transmission among men-who-have-sex-with-men (MSM). Combined Antiretroviral Therapy (ART) introduced since 1997 is hypothesised to have helped control the overall spread of HIV. Our objective was to estimate the impact of ART on HIV incidence in the general population of Bogota. Me...

The rigorous evaluation of the impact of combination HIV prevention packages at the population level will be critical for the future of HIV prevention. In this review, we discuss important considerations for the design and interpretation of cluster randomized controlled trials (C-RCTs) of combination prevention interventions. We focus on three larg...

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...

Objetivos: Evaluar la frecuencia de alteración tiroidea y los factores asociados en los pacientes con VIH/SIDA de un hospital universitario en Colombia. Pacientes y Métodos: Estudio tipo corte transversal de pacientes con VIH/SIDA durante el periodo de 2007 a 2008. Se registró niveles hormonales, inmunológicos, carga viral y tratamiento anti-retrov...

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.

Introduction: The objective of this study was to evaluate the frequency of thyroid function alterations and its associated factors in a group of patients from a university hospital in Colombia. Methods: From June 2007 through June 2008, 636 HIV patients were followed in order to assess the relation of thyroid function with the use of HAART. Res...

In a rural area of Colombia endemic for Rocky Mountain spotted fever, we performed indirect immunofluorescent antibody assays for Rickettsia spp. and Ehrlichia spp. using sera from randomly sampled dogs and horses to test the use of domestic animals as possible sentinels. Antibodies against Ehrlichia spp. were detected in 8 dogs (31.8%). Antibody t...

Thyroid Function Disorders among HIV Positive Patients from a University Hospital in Bogotá Colombia 2007-2008

In the north of Caldas, Colombia, febrile syndromes with positive Weil-Felix reactions have been reported as Murine typhus to the national health authorities. We used indirect immunofluorescence assay (IFA) of serial paired samples to confirm the diagnosis of murine typhus in 14 of 120 patients with a compatible febrile syndrome.

Although there has been increasing number of prevention programs in the city of Cartagena, the incidence of HIV has grown dramatically. Within this social context the purpose of this study is focused on the understanding of how a sociocultural context infuences the notion of risk of HIV contagion. Also, taking into account the promotion of condOMS...

Although there has been increasing number of prevention programs in the city of Cartagena, the incidence of HIV has grown dramatically. Within this social context the purpose of this study is focused on the understanding of how a sociocultural context infuences the notion of risk of HIV contagion. Also, taking into account the promotion of condoms...

Streptococcus pneumoniae es un microorganismo de frecuente aparición como colonizador normal de la nasofaringe y como causante de enfermedad invasora especialmente dentro del grupo de edad de niños menores de 5 años, generando a nivel mundial una mortalidad de hasta 700 000 casos por año en niños menores de 2 años. El estudio de la antigenicidad ca...