Infectious Disease Epidemiology Group

Laith Abu-Raddad, PhD
Principal Investigator
Associate Professor of Public Health
Director of Biostatistics, Epidemiology and Biomathematics Research Core

Ghina Mumtaz, MSc
Senior Epidemiologist
Research Specialist

Hiam Chemaitelly, MSc
Epidemiologist
Research Specialist

Susanne Awad, MSc
Biomedical Engineer
Research Specialist

Yousra Mohamoud, MSc
Epidemiologist
Research Specialist

Diego Cuadros, PhD
Epidemiologist / Biologist
Postdoctoral Research Associate

Silva Kouyoumjian, MSc
Epidemiologist
Research Specialist

Pascale Haddad, MSc
Epidemiologist / Biostatistician
Research Specialist

Ryosuke Omori, PhD
Theoretical Epidemiologist / Ecologist
Postdoctoral Research Associate

Adona Canlas
Research Group Administrator

Karima Chaabna, PhD
Epidemiologist
Postdoctoral Research Associate

Phone: (974) 4492 8321


     
   
     

Research Interests

Our research interests focus on studying the epidemiology of diseases and assessing the impact of interventions. Our main interest is on infectious disease epidemiology with an emphasis on sexually transmitted infections. In addition to HIV and other sexually transmitted infections, we conducted or are currently working on research projects in relation to hepatitis C virus, tuberculosis, influenza, SARS, within-host virology, and the ecology and evolution of infectious diseases. Our methodology expertise emphasizes conventional epidemiologic methods as well as quantitative methods including mathematical modeling and related standard epidemiologic statistical analyses.

Among our research projects:

Understanding the sexual network determinants of the epidemiology of sexually transmitted infections: Quantitative assessment
The global burden of sexually transmitted infections (STIs) is a major public health challenge. The spread of STIs is through sexual networks, but the structure of sexual networks and their role in the epidemiology of STIs are not well understood, particularly in the Middle East and North Africa region (MENA). Even though STIs share the same mode of transmission, the nature of sexual networks can drive different transmission patterns for the different STIs. The proposed research provides an approach to study key STIs collectively, and explore their epidemiological links, using a standardized methodology where all STIs are propagated on the same sexual network structure, thus facilitating comparative analysis.

The specific aims are to

  1. Examine the role of sexual networks in driving STI transmission for a range of STI pathogens.
  2. Infer the structure of sexual networks from STI population-level biomarkers.
  3. Understand the epidemiological overlap and links between different STIs and use this knowledge to infer HIV epidemic potential.
  4. Generate insights and recommendations for informing the design and analysis of STI epidemiologic field studies and surveillance systems.
  5. Generate insights and recommendations for informing the design and analysis of STI epidemiologic field studies and surveillance systems.
Dr. Abu-Raddad is the principal investigator of this scientific study.
Critical assessment of the drivers of the hepatitis C virus epidemic in Egypt: A quantitative approach
Multiple studies have been conducted worldwide to document the prevalence and distribution of hepatitis C virus (HCV) infection in human populations. Even though HCV currently affects about 2% of the world�s population, Egypt has the highest prevalence in the world with 15% of the population infected with the virus. HCV infection and its complications are among the leading and most pressing public health problems in Egypt.

A number of studies have suggested that the HCV epidemic in Egypt was driven by the past implementation of parenteral antischistosomiasis therapy (PAT) in the health campaigns against schistosomiasis. The exact drivers and their relative roles in the epidemic are still not well-understood. Our study is an attempt to evaluate the role of PAT in driving the HCV epidemic, and to identify other drivers and determinants of HCV transmission in Egypt.

The specific aims are

  1. Quantitative assessment of the contribution of PAT and other drivers to the HCV epidemic in Egypt.
  2. Quantitative assessment of the current determinants of HCV transmission in Egypt.
Dr. Diego Cuadros and Dr. Laith Abu-Raddad are the principal investigators of this scientific study.
The Middle East and North Africa HIV/AIDS epidemiology synthesis project

The Middle East and North Africa (MENA) continues to be viewed as the anomaly in the HIV/AIDS world map and �a real hole in terms of HIV/AIDS epidemiological data�. The apparent lack of HIV data has led to many controversies on the status of the epidemic in MENA, with conflicting views as to the role of MENA�s socio-cultural values in shaping the epidemic in this region. None of these views has been substantiated by epidemiological data. It is essential to understand where HIV is being transmitted in MENA in order to take advantage of probably a narrowing window of opportunity to stem the tide of HIV transmission in the region.

The Middle East and North Africa HIV/AIDS Epidemiology Synthesis Project is the most comprehensive research project on HIV/AIDS in the history of the MENA region. It is a scientific assessment and data-driven epidemiological synthesis of HIV spread in MENA based on a systematic literature review and analysis of thousands of widely unrecognized publications, reports and data sources extracted from the scientific literature or collected from sources at the local, regional and national levels. The project is conducted through a collaborative partnership with the World Bank, the Joint United Nations Programme on HIV and AIDS and the World Health Organization.

The specific aims are to conduct epidemiological analyses and systematic reviews on MENA to

  1. Synthesize the biological evidence on HIV in high risk groups, bridge populations, vulnerable populations, and the general population.
  2. Synthesize the evidence on risk behavior to better understand sexual risk patterns, sexual networks, and injecting drug use patterns in the same risk population groups in Aim 1.
  3. Review the settings of vulnerability such as those of prisoners, youth, street children, refugees, internally displaced persons, migrant workers, mobile populations, runaway women and military personnel.
  4. Review levels, sources, and nature of HIV/AIDS knowledge in the same risk population groups in Aim 1.
  5. Synthesize the biological evidence on proxy measures and biological markers including herpes simplex virus type 2 (HSV-2), human papillomavirus (HPV) and cervical cancer levels, bacterial sexual transmitted infections (STIs), and hepatitis C virus (HCV) to probe nature of sexual risk patterns, sexual networks, and injecting drug use patterns in the same risk population groups in Aim 1.

Dr. Abu-Raddad is the principal investigator of this scientific study.

Understanding the role of biological cofactors including HIV co-infections in HIV epidemiology in sub-Saharan Africa

More than 2.5 million new HIV infections occurred worldwide during 2008, the majority of which are in sub-Saharan Africa. Twenty-five years into the HIV pandemic, effective HIV prevention strategies remain urgently needed and the epidemiology of HIV in sub-Saharan Africa continues to be far from being well-understood. Studies over the last few years have suggested a role for non-sexually transmitted co-infections in fueling HIV infectious spread. Such a role may explain the massiveness of the epidemic in Africa and why HIV has spread into the general population characterized by low levels of reported risk behavior.

The specific aims are to:

  1. Conduct epidemiologic analyses and systematic reviews of the biological interaction between HIV and a number of non-sexually transmitted co-infections such as malaria, tuberculosis (TB), schistosomiasis, lymphatic filariasis, other helminthic infections, and leishmaniasis.
  2. To build a database of HIV plasma viral load measurements from all regions of the world, assess differences in viral load between regions, and determine whether higher levels of viral loads may have driven higher infectivity of African subjects.
  3. To conduct mathematical modeling studies to quantify the epidemiologic impact on HIV of the synergy between HIV and biological cofactors including co-infections, and assess the impact of interventions that target these biological cofactors.

Dr. Abu-Raddad is the principal investigator of this scientific study.

The Middle East and North Africa hepatitis C virus epidemiology synthesis project

Transmission of blood-borne pathogens occur routinely in resource-limited settings and are conceived as a major public health problem in the developing world. The Middle East and North Africa (MENA) is no exception to this rule and there appears to be a lack of sufficient resources to screen blood and to sterilize medical equipment in several countries. Reuse of needles/syringes and major/minor surgery in hospitals were repeatedly linked to hepatitis C (HCV) infection in MENA. One of the countries of the region, Egypt, has by far the highest prevalence of this infection worldwide.

HCV is about six times as infectious as HIV through the parenteral route and is most often transmitted before HIV; therefore it can be used as a proxy biomarker to explore the HIV epidemic potential through this mode of transmission. HCV prevalence levels draw a map of the risk of HIV parenteral transmission across the different risk groups in a population.

The specific aims of this project are to:

  1. Synthesize the biological evidence on HCV in populations at direct risk, indirect risk, special clinical populations and the general population by conducting a systematic review of HCV prevalence and incidence in different population groups in MENA.
  2. Characterize potential HIV spread through the parenteral route using the synthesized biological evidence on HCV as a proxy measure.

Dr. Abu-Raddad is the principal investigator of this scientific study.

Modes of HIV transmission analysis in the Middle East and North Africa

Though HIV prevention is best achieved by addressing the structural factors that drive risk behavior practices, the first priority in the public health sector is on addressing the direct factors that put individuals at risk of HIV exposure. This project is concerned with identifying the direct exposures that put individuals at risk of HIV infection in countries in the Middle East and North Africa. The patterns of transmission analysis is conducted to inform public health policy decisions.

The specific aims are to:

  1. Conduct a systematic review of all HIV epidemiological data for each country considered.
  2. Analyze the distribution of new HIV infections by mode of exposure using a mathematical model developed by the UNAIDS Reference Group on Estimates, Modeling and Projections.
  3. Provide in-country training to the national consultants and national project teams on the use of the modes of transmission model (MoT).
  4. Provide recommendations to the Ministries of Health and National AIDS Programs for prioritizing prevention efforts and addressing the gaps in scientific evidence in relation to HIV epidemiology.

Dr. Abu-Raddad is the principal investigator of this scientific study.

Design of an optimal package of HIV prevention interventions in Sub-Saharan Africa: The Prevention Rx Project

Twenty-five years into the HIV pandemic, HIV prevention strategies remain urgently needed. No single HIV prevention strategy will control the HIV epidemic; thus, multi-layered and multi-component prevention will be needed. Despite evidence of partial efficacy for several interventions, currently no single intervention offers a "magic bullet". Instead, a multi-component package of synergistic, evidence-based, biomedical, and behavioral interventions must be assembled and tailored to be appropriate, acceptable, and deliverable to priority subpopulations for risk reduction at individual, dyadic, and sexual network levels. With the Prevention Rx Project, we propose to develop a coordinated, multi-component HIV prevention package of evidence-based biomedical and behavioral interventions that will be individually-tailored and targeted to maximize coverage and impact on HIV incidence in an African population.

The specific aims are to:

  1. Conduct epidemiologic analyses, systematic reviews, and mathematical modeling to identify modifiable determinants of heterosexual HIV transmission with the highest population-attributable fraction in sub-Saharan Africa, estimate the impact of targeted prevention strategies directed at these determinants, and select components of a prevention package based on these analyses.
  2. Pilot data collection for identification of highest-risk individuals (HIV discordant couples, HIV-infected persons, and HIV-negative persons with high-risk behaviors), with integration and targeting of behavioral and biomedical prevention interventions into population-based, home-based HIV counseling and testing (HBCT) programs.
  3. Design a community-randomized effectiveness trial of a comprehensive, targeted, biomedical (e.g. male circumcision, ART) and behavioral HIV prevention package for East and Southern Africa in the context of HBCT.

Our role in this major international collaboration is to direct the mathematical modeling component in this project in collaboration with the HIV mathematical modeling team at Imperial College London. The principal investigator of this project is Professor Connie Celum at the University of Washington.

More information can be found at http://depts.washington.edu/uwicrc/research/studies/MP3.html

Understanding the pathogenesis of herpes simplex virus-2 infection (HSV-2)

Herpes simplex virus 2 (HSV-2), a sexually transmitted infection, is the leading cause of genital ulcers worldwide. Infection is life-long and is characterized by repeated asymptomatic and symptomatic episodes of virus shedding that are initiated when virus is released from neurons into the genital tract. The pattern of HSV-2 release from neurons, which harbor the virus, into the genital tract is poorly understood. This project aims to understand the pathogenesis of HSV-2 and intra-host biological interactions between HSV-2 and HIV infections. The project is conducted in collaboration with the Herpes Simplex Virus-2 biology group at the University of Washington/ Fred Hutchinson Cancer Research Center.

The specific aims are to:

  1. Design a mathematical model of HSV-2 pathogenesis and use it to explain the data of daily quantification of HSV-2 in mucosal swabs from patients with herpetic genital ulcers.
  2. Understand the impact of acyclovir treatment on the pathogenesis, viral production, and transmissibility of HSV-2.
  3. Understand the intra-host biological effects of HSV-2 infection on increasing susceptibility to HIV infection and transmissibility of HIV infection.

Our role on this scientific study is to provide mathematical modeling expertise in design and conduct of the study. The principal investigator and lead researcher of this project is Dr. Joshua Schiffer.

Human papillomavirus in Arab women: Molecular epidemiologic, clinico-pathological, serological, and vaccine impact studies in select Arab countries

Cervical cancer is the second most common cancer that affects women worldwide. Molecular epidemiological studies have identified human papillomavirus (HPV) infection as the major cause of cervical cancer. HPV types frequently detected in cervical cancers are classified as high-risk viruses (such as types 16, 18, 31, 33, 52 and 58), while those rarely found in cancer are designated low-risk viruses (such as types 6 and 11). The most frequent high-risk HPV types detected worldwide are HPV 16 and 18.

Recently, a prophylactic vaccine has been shown to be efficacious in preventing persistent HPV infections. The vaccine aims to prevent infection from 4 HPV types (6, 11, 16, and 18). The effectiveness of this vaccine is dependent on the prevalence of HPV 16 and 18 types in a population. In Arab countries, data on the high-risk HPV prevalence are limited and needs to be established before mass introduction of HPV vaccination. Recent studies suggest that the distribution of HPV infections in Arab countries can be different from other regions. Given the importance of HPV vaccination, we will investigate the geographic distribution of HPV infection in Arab countries and assess the epidemiological impact of such vaccine if administrated.

The goal of this proposal is to:

  1. Initiate a molecular epidemiology study to identify the most prevalent types and variants of HPV in select Arab countries.
  2. Investigate the correlation between HPV variants and the clinico-pathological features of HPV infection in Arab women with HPV lesions.
  3. Conduct a sero-epidemiological study to identify populations who have been exposed to HPV infection and to characterize their immune response to HPV infection.
  4. Assess quantitatively the epidemiologic impact of HPV vaccination and inform policy decisions on HPV vaccination.

Our role in this collaboration is to direct the mathematical modeling component in this project to assess the epidemiological impact of HPV vaccination. The principal investigator of this study is Dr. Ali Sultan at the Weill Cornell Medical College � Qatar.



Last modified on Monday, 31-Mar-2014 09:36:55 AST