Dengue is the fastest-spreading mosquito-borne viral illness in the world, and has become a leading cause of morbidity in many tropical and subtropical regions – including outbreaks in recent years in Mexico, Brazil, Colombia, the Dominican Republic, and other Latin American countries. The direct impact of these outbreaks is exacerbated by the stress they place on public health systems, as hospitals become overwhelmed by a surge in cases of dengue as well as “false alarms” from non-dengue fevers. 

Early-warning systems for outbreaks are becoming an increasingly important tool to mitigate the impact of outbreaks for dengue and other diseases, potentially limiting the spread of the illness as well as enabling public health systems to respond more efficiently and effectively.

Current Imperial College London faculty previously participated in an international, World Health Organization (WHO)-led effort to study predictors of dengue outbreaks and develop an early dengue outbreak warning and response system (EWARS). Public health professionals hoping to make this kind of impact can work with Imperial’s world-class faculty from anywhere in the world through the online Global Master of Public Health. 

From Alarm Variables to EWARS 

The first task of this project was to create a statistical model for dengue outbreaks that met the criteria of having a high sensitivity (number of true outbreak detections) and a low number of false positives. This work was led by Dr. Leigh Bowman, then at Umeå University in Sweden and now a Teaching Fellow at Imperial College as well as Consultant Epidemiologist with the WHO. 

Using data from 2007 to 2013 from Mexico, Brazil, Dominican Republic, Malaysia, and Vietnam, researchers sought to define dengue outbreaks based on numbers of hospitalizations and then retrospectively predict them using changes in three key types of alarm variables:

• Meteorological: Outdoor temperature, rainfall, relative humidity
• Epidemiological: Mean age of infection, circulating type of virus, probable dengue cases, hospitalized dengue cases
• Entomological: Various factors indicating the presence and extent of the specific Aedes mosquito that carries dengue

Logistic regressions were performed on these “alarm variables” to develop coefficients for each to build a predictive model for outbreaks. Traditional epidemiological variables, and probable dengue cases in particular, had the greatest predictive potential, but meteorological variables — particularly mean temperature — were also effective predictors in Mexico and Brazil. Entomological variables, meanwhile, required further study. 

This work provided a foundation for the development of the “Early Dengue Outbreak Warning and Response System” (EWARS), a user-friendly, open-source software tool that provides an “alarm system” for dengue outbreaks based on these indicators. EWARS defines a moving average number of dengue cases within a “normal” state for a given set of local conditions, and then defines an alarm threshold for when these indicators increased the probability of an outbreak beyond a specified level requiring action.

The initial EWARS tool and a revised version (EWARS-R) were developed and tested in Mexico, Brazil, and Malaysia, achieving promising results for both sensitivity and positive predictive values (the proportion of true positives as opposed to false alarms, abbreviated PPV):

• Mexico: 79-100% sensitivity, 50-83% PPV
• Brazil: 83-99% sensitivity, 40-88% PPV
• Malaysia: 50-99% sensitivity, 71-80% PPV

District health managers across all 30 study districts that had used EWARS in the field for seven to 10 months were also surveyed as part of the continuing calibration and development of this tool. Respondents indicated an overall consensus that EWARS is useful overall, but also had a number of suggestions for operational improvements to be included in future versions. This work will continue as the project partners work with stakeholders in dengue-prone countries to scale up and expand the use of EWARS.

Global Collaboration for Global Impact

This research has drawn support from leading international institutions for  its potential to mitigate the impact of dengue outbreaks in different, country-specific contexts worldwide. Primary funding came from the European Commission to the International Research Consortium on Dengue Risk Assessment, Management and Surveillance network.

In addition to Dr. Bowman, these two research papers included global contributors from Europe, Asia, and Latin America. Co-authors included representatives from universities in the United Kingdom and several other European countries; the Ministries of Health of Mexico, Brazil, Malaysia, and the Dominican Republic; and the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR).

If you’re looking to make this type of impact on the spread of infectious diseases or other pressing public health issues in Latin America or globally, the online Global Master of Public Health from Imperial College of London’s School of Public Health makes the next step of your career accessible from anywhere in the world. 

Cardiovascular disease is one of the biggest public health challenges facing America today by any measure. It is the leading cause of mortality and morbidity in the U.S., resulting in 800,000 deaths and 6 million hospital admissions per year. Cardiovascular disease costs the economy $318 billion annually in healthcare costs and an additional $237 billion in lost productivity.  

Sodium consumption is the leading modifiable risk factor for both cardiovascular disease and high blood pressure, so it’s no surprise that in 2016 the U.S. Food and Drug Administration (FDA) proposed adopting voluntary 2-year and 10-year sodium targets for commercially processed and prepared foods. These targets are in line with policies that have been proven to reduce sodium intake in the U.K. and other European countries. However, the U.S. Congress has moved to block the FDA from issuing such standards, in part due to questions about their effectiveness.

A recent study led by Imperial College of London’s Dr. Jonathan Pearson-Stuttard in collaboration with U.S. and other international researcher institutions sheds some light on these important questions. Aspiring public health professionals anywhere in the world can work on impactful projects like these with the 100% online Global Masters in Public Health from Imperial College London.

Evaluating the Effectiveness and Costs of Sodium Targets

Researchers used the previously-validated US IMPACT Food Policy Model to project the standards’ impact on cardiovascular disease (CVD) cases and deaths, quality-adjusted life years (QALYs), and cost-effectiveness over a 20-year time period. Because the standards are voluntary, the researchers also modeled several different compliance scenarios to estimate of the range of potential outcomes.

• 100% compliance with 10-year targets: The optimal scenario would prevent 450,000 CVD cases, gain 2.1 million QALYs, and produce cost savings of $41 billion.

• 50% compliance with 10-year targets: The moderate scenario would prevent 220,000 CVD cases, gain 1.1 million QALYs, and save $19 billion in costs.

• 100% compliance with 2-year targets, 0% compliance with 10-year targets: The pessimistic scenario would prevent 120,000 CVD cases, gain 700,000 QALYs, and save $12 billion in costs.

A Monte Carlo sensitivity analysis indicated that all three scenarios yielded a greater than 80% probability that the standards would be cost-effective by 2021 and cost-saving by 2031, making a clear case that these policies make sense from a health as well as an economic perspective. These cost-saving estimates included both industry costs from reformulating products to meet the targets, as well as government costs for administering the policy itself. 

It’s also worth noting that the absolute health benefits of the policy would be roughly 50% higher for men than women, owing to their higher sodium intake. The policy would also benefit older Americans and black Americans. The impacts on black Americans is important considering the disproportionate CVD burdens faced by this population. This factor makes the policy effective from an equity perspective (as well as in absolute terms).  

International Collaboration Key for Nutritional Health

As noted above, the FDA’s proposed standards for the U.S. were based on those implemented in the U.K. and other European countries. Similarly, the research team for this project spanned both continents. Co-authors of the report include Dr. Pearson-Stuttard of Imperial College London as well as researchers from the University of Liverpool, Tufts University, the Medical University of Gdansk, Poland, and the American Heart Association. 

The collaboration with U.S. researchers at Tufts and the American Heart Association are part of an extensive track record of collaboration between Imperial College and American institutions. In fact, U.S. researchers were the co-authors for nearly 8,000 papers published by Imperial researchers from 2015 to 2017, more than any other country.

The study was conducted as part of the Food-PRICE (Food Policy Review and Intervention Cost-Effectiveness) project at Tufts, a collaboration of US and European researchers seeking to identify population-level nutrition strategies to improve public health outcomes for Americans. Areas of focus for the project include heart disease, stroke, diabetes, obesity, and cancer in the US.

If you’re interested in making an impact on public health and public policy in the US — or anywhere else in the world — the Global Master of Public Health degree from Imperial College gives you the chance to collaborate with peers and study on your schedule from wherever you are. 

The hepatitis C virus (HCV) is a global public health scourge, infecting more than 70 million people worldwide and ultimately causing liver complications including cirrhosis and cancer in 10-20% of cases. HCV was responsible for more than 475,000 deaths worldwide in 2015, and future cases are projected to expand most in China, India, and Pakistan. 

However, the discovery of direct-acting antiviral (DAA) drugs in 2014 gave new hope to the fight against HCV, offering greater effectiveness and less side effects than previous treatments. This breakthrough inspired the World Health Organization (WHO) to declare a new goal of eliminating HCV as a public health threat, with targets of reducing incidence by 80% and mortality by 65% by 2030. 

While these developments are hopeful, are they realistic? Research from Imperial College London’s School of Public Health examines the feasibility of achieving the WHO goals, demonstrating the kind of globally-important research that students of Imperial’s online Global Master of Public Health can work on.

Modeling a Complete Package of Interventions 

As reflected by the WHO targets, an effective response to HCV has two components: the reduction of incidence, and the reduction of mortality. hile the discovery of DAAs offers a promising means of treating HCV cases, it does not directly reduce the transmission of the virus, which is typically associated with blood transfusions, healthcare-related injections, and injection drug use. 

Thus, Imperial researchers sought to model not only improved access to DAA treatment but a combined package of strategies that include enhanced prevention and diagnosis programs as well. These interventions were modeled as a sequence added to the status quo, with each intervention building on the next. 

1. Blood safety and infection control assumed to reduce infection among non-intravenous drug users by 80% by 2020
2. Harm reduction for intravenous drug users, including opioid substitution therapy and needle and syringe programs, reducing infection risks by 75%
3. Offering DAAs immediately at diagnosis regardless of disease stage
4. Outreach screening enabling 90% of HCV cases to be diagnosed by 2030

As expected, the application of all four of these strategies achieved the best modeled outcome. Coming very close to the WHO goals, the comprehensive package of interventions is projected to reduce HCV incidence by 81% and mortality by 61% by 2030. 

• Prevention (Interventions 1 & 2): 14.1 million new infections averted
• Treatment (+ Intervention 3): 640,000 avoided deaths from cirrhosis and liver cancer
• Screening (+ Intervention 4): Total of 15.1 million new infections avoided and 1.5 million avoided cirrhosis and liver cancer deaths

The model shows that the mortality elimination target of 65% would be reached by 2032 under this scenario, although it is achievable by 2030 if diagnosis coverage through outreach screening covers 95% of HCV cases instead of 90%. 

On the other hand, if the comprehensive package is not fully implemented in China, India, or Pakistan – the countries of highest projected future cases – the global incidence would be increased only 69% by 2030, pushing back the achievement of these goals to 2047. Thus, the study underscores the importance of action in these specific countries to achieve the WHO goals on HCV elimination. 

Doing Globally-Relevant Work at Imperial

This work was funded by the Wellcome Trust and conducted by researchers from the MRC Centre for Global Infectious Disease Analysis at Imperial College London, including lead author Dr. Alastair Heffernan. With 175 researchers, the MRC Centre is one of the world’s largest research centers for infectious disease modeling, producing impactful interdisciplinary research on diseases such as Ebola, Zika, HIV, malaria, and tuberculosis. 

Research like this paper, published in The Lancet and providing direct input to WHO work, is emblematic of the globally-relevant, high-impact public health research that Imperial College London is renowned for. Now, thanks to the flexible, 100% online Global Master of Public Health degree, it’s possible for students anywhere in the world to work on challenges like HCV alongside Imperial’s world-class faculty.

While Africa’s high infectious disease burden has drawn the most attention from the international public health community, the continent is also facing rising impacts from non-communicable diseases (NCDs), including diabetes. Similarly, crises of food insecurity in the region have obscured the risks of obesity accompanying Africa’s increasing economic growth and urbanization. 

This is changing, however, with international organizations as well as national governments coming together in recent years to bring a new focus to these related issues. Public health researchers at Imperial College London have provided critical support for these efforts with the first detailed analysis of obesity and diabetes in Africa.

The findings could help inform health interventions throughout the continent. Public health students and professionals looking to make this kind of international impact in Africa or anywhere in the world can learn alongside Imperial’s world-class faculty through the online Global Master of Public Health degree. 

Public Health Risks in a Fast-Growing Population 

In 2016, the World Diabetes Foundation (WDF), the East African Diabetes Study Group (EADSG), and the Tanzanian Ministry of Health convened an international NCD Symposium in Dar Es Salaam. The event brought together government Ministries of Health from 17 countries, the World Health Organization (WHO), the African Union, and the Global NCD Alliance to share experiences and lessons learned about this rising public health threat.

The culmination of the event was the signing of the 2016 Dar Es Salaam Call to Action on Diabetes and Other Non-Communicable Diseases (NCDs), which committed countries across the continent to a number of steps including the development national NCD strategies and action plans based on available data. 

Imperial College researchers led a team to provide the robust datasets needed to inform these policies working as part of the NCD Risk Factor Collaboration – Africa Working Group,. They pooled data from population studies from 1980 to 2014 to estimate trends in mean body mass index (BMI) and diabetes prevalence in 53 countries across all five regions (central, eastern, northern, southern, and western) of Africa. 

The result of this analysis confirmed the urgency of addressing the linked challenges of obesity and diabetes:

• From 1980 to 2014, mean BMI increased from 21 to 23 kg/m² in men, and from 21.9 to 24.9 kg/m² in women, increasing over time across all regions 
• Diabetes prevalence more than doubled, rising from 3.4% to 8.5% in men, and from 4.1% to 8.9% in women 
• These increases in obesity and diabetes were associated with increases in gross domestic product, indicating these trends could worsen with continuing economic growth

In their conclusions, the study’s authors emphasized the importance of developing better monitoring data as African countries ramp up their efforts to address diabetes. According to co-author Dr. James Bentham of Imperial College, “Our findings are based on the largest dataset ever collected describing these conditions in Africa. As the continent experiences higher burdens of obesity and diabetes, we also need to use better data to track the performance of countries in preventing these conditions.”

Collaborating Across Continents

The study’s co-lead authors were Dr. Bentham and Dr. Majid Ezzati of Imperial College London, in collaboration with academics from the South African Medical Research Council (SAMRC). They worked with the wider NCD Risk Factor Collaboration, a global network of public health scientists studying risk factors for non-communicable diseases such as diabetes, cancer, and cardiovascular disease. 

The work was funded by the UK’s Wellcome Trust as well as SAMRC, proving further that achieving global impacts often requires global collaboration. Public health students and professionals looking to work on this type of difference-making research about issues everywhere in the world, from anywhere in the world, can do so with Imperial College’s 100% online Global Master of Public Health degree. 

The United Nations has declared reducing inequality as one of its Sustainable Development Goals (SDGs) both within and among countries. This includes a target for countries to adopt social protection policies that “progressively achieve greater equality.” Healthcare is a core concern of those social protection policies, and a recent study shows that expanding access to primary healthcare has gone hand-in-hand with reducing racial inequality in Brazil.

The research, led by Dr. Thomas Hone of Imperial College of London’s School of Public Health, provides important support for continued efforts to expand primary care access in the face of economic and political turmoil in Brazil. Public health students and professionals looking to produce this type of impactful work can pursue an online Global Master of Public Health from Imperial College from anywhere in the world. 

Reducing Unequal Health Outcomes in Brazil

Brazil is a compelling case study for policies that address both healthcare access and inequality. It is a large developing economy with one of the highest levels of income inequality in the world, as well as severe disparity in health outcomes across income as well as educational, racial, and socio-economic lines. In particular, black and pardo (mixed race) populations suffer from lower average incomes, higher incidence of infectious diseases, higher mortality rates, and shorter life expectancy.

The Estratégia Saúde da Família (ESF) has been one of the most prominent policies seeking to reach these populations and achieve universal healthcare in Brazil. Under the ESF, family health teams deliver a broad range of free primary healthcare services at the community level. Since its start in the 1990s, the ESF has grown to provide services for more than 120 million Brazilians, with the greatest focus in municipalities with smaller populations, higher levels of poverty, and higher percentage of black and pardo people. 

Previous research showed that the ESF has been broadly effective in lowering infant mortality, avoidable hospitalizations, and deaths from cardiovascular and respiratory diseases. This new Imperial College study sought to specifically evaluate how the program has impacted different racial populations. Researchers examined municipal-level mortality and demographic data for nearly 600,000 Brazilians and compared it with municipal ESF coverage.

The conclusions are stark: expanding ESF coverage resulted in a decline in the rate of avoidable deaths among black and pardo populations of 15.4% between 2000 and 2013, more than double the 6.8% decline in white populations. This decline was specifically driven by fewer deaths from infectious diseases, nutritional deficiencies and anaemia, diabetes, and cardiovascular disease.

While these results point to significant progress made in reducing inequality due to the ESF, the study also revealed this sobering finding: the rates of avoidable deaths in the black and pardo populations were still 17-23% higher than in the white population over the same time period. Thus, the Imperial research found that it is critical to continue prioritizing the expansion of this program, especially in Brazil’s current economic and political climate. 

Global Impacts of Universal Healthcare Research 

This study is an important contribution to the literature because the limited research to-date on linkages between expanding primary healthcare and reducing inequality has occurred solely in high-income country contexts. Thus, the study’s authors filled a significant gap by providing a relevant case study for other developing countries.

To do this work, Imperial College’s Dr. Thomas Hone led a team of researchers from several institutions across Brazil, including the Centre for Data and Knowledge Integration to Health (CIDACS) and the Instituto de Saúde Coletiva in Salvador, the Center for Epidemiological Studies in Health and Nutrition at the University of São Paulo, and the Institute of Social Medicine at  Rio de Janeiro State University.

If working on globally-relevant problems with leading international research institutions sounds like the next step for your career, Imperial College’s 100% online Global Master of Public Health degree might be the next step in your education.

Reductions to government social support programs have costs, and they can be particularly severe for vulnerable populations. Budget cutbacks have been implemented as a solution to the recession that has gripped Brazil since 2015, but a study led by Dr. Thomas Hone of Imperial College of London indicates that these austerity measures could result in significant collateral damage to public health.

Imperial College of London’s School of Public Health has built an international reputation for exactly this kind of highly-relevant, impactful research. Students across the world can be a part of this important work by enrolling in Imperial’s 100% online Global Masters of Public Health program.  

A Treatment Worse Than The Disease?

Since 2015, Brazil has been mired in a severe economic crisis, with GDP falling more than 8%. This recession has led to increasing unemployment, particularly among low-income populations, and an increase in the rate of people living below poverty.

Consequentially, the austerity measures implemented by the government will result in significant cuts to two critical programs for poverty alleviation and health care: the Bolsa Familia Programme (BFP) and the Estrategia Saude da Familia (ESF). 

• The BFP covers about 25% of Brazil’s population, and provides cash transfers for families in need if they meet conditions of school attendance, vaccinations, and health checkups for children, and prenatal and postnatal doctor’s visits for new mothers. 

• The ESF provides community-based primarily healthcare to local populations in need, with family health teams providing services including basic curative care, health promotion and education, and targeted programs for HIV/AIDS, cardiovascular health, and other issues. 

For this study, researchers from Imperial College and their collaborators modeled the potential impacts to child mortality in Brazil from cuts to these two programs. They employed a microsimulation approach that models individual-specific characteristics and probabilities in order to provide greater accuracy of policy effects compared to traditional methodologies, which use only the average values in a population. Using municipal-level data, researchers simulated changes in poverty rates and other socioeconomic variables through 2030 and then used these results to project mortality and hospitalization rates for children younger than 5 years old. 

This simulation was carried out across three different economic scenarios, corresponding with durations of economic crisis ranging from 3 to 7 years old, as well as different rates of poverty increase. Health outcomes were then compared across two policy scenarios: one in which fiscal austerity measures are maintained through 2030, and one in which BFP and ESF coverage is preserved and allowed to keep up with changes in the poverty rate.

The results of this modeling study are sobering, indicating a substantial increase in childhood mortality even under a mild crisis scenario if austerity measures remain in place:

• Mild Crisis (3 years): 7% increase in child mortality rate, with nearly 14,000 avoidable childhood deaths

• Medium Crisis (5 years): 8.6% increase in child mortality rate, with nearly 20,000 avoidable childhood deaths

• Prolonged Crisis (7 years): 9.5% increase in child mortality rate, with more than 23,000 avoidable childhood deaths

Across all scenarios, cuts to these programs have disproportionate impacts on at-need municipalities, reversing a trend in declining inequality in health outcomes in Brazil and compromising efforts to achieve the UN Sustainable Development Goals (SDGs). 

International Ramifications

These research findings have the potential to influence not only Brazil’s policies but those of countries around the world. While there have been several studies examining the impacts of economic crises on health outcomes in high-income countries, research on impacts in low- and middle-income countries (LMICs) has been lacking. This study helps to fill that gap, providing support for maintaining social support and healthcare programs even in the midst of economic challenges in these contexts. 

Imperial College of London’s Dr. Hone worked with a team of researchers from Brazil as well as the US to conduct this study. Co-authors represented the Universidade Federal da Bahia, the René Rachou Institute in Minas Gerais, the Institute for Applied Economic Research in Rio de Janeiro, and the University of São Paulo in Brazil, and Stanford and Harvard Universities in the U.S.

If you want to work on this kind of internationally-conducted, internationally-impactful research in your career, the online Global Masters of Public Health degree at Imperial College gives students anywhere in the world the opportunity to learn on their own schedule.