One Health interventions that address human, animal, and environmental health domains are critical for controlling the global challenge of antimicrobial resistance (AMR). These interventions can target upstream conditions, such as prevention strategies like vaccination or policies, to restrict antimicrobial use in humans, animals, and plants, with a goal to reduce the selective pressure that can drive the emergence and expansion of drug-resistant pathogens. Downstream, environmental hygiene initiatives can target transmission pathways between people and animals to limit exposure to drug-resistant pathogens. Holistic, transdisciplinary approaches that address the factors driving antimicrobial use in people, animals, and the environment hold promise to help curb the global challenge of AMR.
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Application of One Health Principles to the Control of Antimicrobial Resistance
Meghan F. Davis
Article
Big Data and Urban Health
Mark Stevenson, Jason Thompson, and Thanh Ho
Understanding the varied effects of urban environments on our health have arisen through centuries of observation and analysis. Various units of observation, when compiled spatially or linearly, have provided considerable understanding of the causal pathways between environmental exposures in cities and associated mortality and morbidity. With growing urban agglomerations and a digital age providing timely and standardized data, unique insights are being provided that further enhance the understanding of urban health. No longer is there a potential lack of urban data; over the 2010–2020 decade alone, the resolution and standardization of satellite and street imagery, for example, alongside methods of artificial intelligence such as self-supervision methods, have meant that technology and its capacity have surpassed the accuracy and resolution of many administrative data collections typically used for urban health research. From Bills of Mortality in 1665 to 20th century surveillance systems to the innovation and global reach in the period of “big data,” data has been the mainstay of decision support systems over the centuries. This new world of big data characterized by volume, velocity, variety, veracity, variability, volatility, and value is paramount to answering the significant urban health challenges of the 21st century.
Article
Burn-Related Injuries
Ashley van Niekerk
A burn occurs when cells in the skin or other tissues are destroyed by hot liquids (scalds), hot solids (contact burns), or flames (flame burns). Injuries to the skin or other organic tissue due to radiation, radioactivity, electricity, friction or contact with chemicals are also identified as burns. Globally, burns have been in decline, but are still a major cause of injury, disability, death and disruption in some regions, with about 120,000 deaths and 9 million injuries estimated in 2017. Low-to-middle-income countries carry the bulk of this burden with the majority of all burn injuries occurring in the African and Southeast Asia regions. Thermal injuries are physically painful and may leave disabling scars not only to the skin or the body, but also impair psychological wellbeing. Severe injuries often impose significant psychological, but also educational consequences and social stigmatization, with the consequent adjustments exacerbated by a range of factors, including the circumstances of the burn incident, the severity and site of the injury, the qualities of the affected individual’s personality, and the access to supportive interpersonal and social relationships. The contributions of: economic progress, enhanced environmental and home structures, energy technology, and safety education interventions have been reported as significant for burn prevention. Similarly, legislative and policy frameworks that support access to modern energies such as electricity, govern domestic appliances and heating technology, and control storage and decanting of fossil fuels are important in energy impoverished settings. The recovery of burn survivors is affected by the availability of specialized treatment, physical rehabilitation and psychosocial support to burn victims and families, but which is still limited especially in resource constrained settings.
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Child Development, Major Disruptive Events—Public Health Implications
Tracy Vaillancourt and Peter Szatmari
The COVID-19 pandemic has upended nearly all the safeguarding systems in the lives of children and youth, such as family life, school, extracurricular activities, sports, unstructured social opportunities, health care, and church. With many of the typical promotive and protective factors disrupted all at once, and for so long, the mental health of children and youth has deteriorated in many areas, but not all, and for many children and youth, but not all. It is important to acknowledge, however, that the mental health of children and youth was in crisis before the pandemic, with 1 in 7 children and youth worldwide having a mental disorder. Given the continued decline in this area of health, children and youth may well be on the cusp of a “generational catastrophe” that could involve lasting harms if immediate action is not taken. Of particular concern are marginalized and vulnerable children and youth—they are the ones unduly enduring the brunt of this global crisis. Accordingly, child and youth mental health recovery must be prioritized, along with the reduction of inequity within and across countries. A commitment to public health strategies that never include harming children and youth as a tolerated side effect must also be made.
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Drowning: Global Burden, Risk Factors, and Prevention Strategies
Aminur Rahman, Amy E. Peden, Lamisa Ashraf, Daniel Ryan, Al-Amin Bhuiyan, and Stephen Beerman
Drowning has been described as a major global public health problem and has recently been acknowledged by a United Nations Declaration on Global Drowning Prevention. While drowning impacts countries of all income levels, the burden is overwhelmingly borne by low- and middle-income countries (LMICs) who account for 90% of the global death toll. In addition, there is scarce data collection on drowning in LMICs, so the magnitude of drowning may be far greater than is represented. A range of factors including sex, age, education, income, access to water, a lack of swimming skills, certain occupations like commercial fishing, geographically isolated and flood-prone locations, preexisting medical conditions, and unsafe water transport systems, influence the risk of drowning. Some behavioral factors, such as alcohol or drug consumption, not wearing life jackets, and engaging in risky behaviors such as swimming or boating alone, increase drowning risk. Geopolitical factors such as migration and armed conflict can also impact drowning risk. There is a growing body of evidence on drowning prevention strategies. These include pre-event interventions such as pool fencing, enhancing community education and awareness, providing swimming lessons, use of lifejackets, close supervision of children by adults, and boating regulations. Interventions to reduce harm from drowning include appropriate training for recognition of a drowning event, rescue, and resuscitation. An active and/or passive surveillance system for drowning, focusing on individual settings and targeting populations at risk, is required.
Drowning requires coordinated multisectoral action to provide effective prevention, rescue, and treatment. Therefore, all countries should aim to develop a national water safety plan, as recommended in the WHO Global Report on Drowning. Further research is required on the epidemiology and treatment of drowning in LMICs as well as non-fatal and intentional drowning in both high-income countries (HICs) and LMICs. Effective and context-specific implementation of drowning prevention strategies, including pilot testing, scale up and evaluation, are likely to help reduce the burden of both fatal and non-fatal drowning in all countries.
Article
Firearm Injuries and Public Health
Linda Dahlberg, Alexander Butchart, James Mercy, and Thomas Simon
An important function of public health is to prevent injuries or to lessen their impact when they occur. An estimated 251,000 people worldwide die each year from a firearm-related death and many more suffer nonfatal injuries with consequences that can last a lifetime. Firearm injuries, which include those that are intentionally self-inflicted, unintentional, or from an act of interpersonal violence, are heavily concentrated in the Americas, driven largely by firearm homicides. Firearm-related deaths and injuries disproportionately impact males and younger populations and are associated with factors such as access, substance use, adverse childhood experiences, involvement in high-risk social networks, drug trafficking, density of alcohol outlets, and neighborhood and social disadvantage. While progress is being made to understand firearm injuries and how to effectively prevent them, much more needs to be done to improve the availability and timeliness of data; apply the knowledge that is generated to effectively reduce firearm-related injuries, deaths, and costs; strengthen the scientific infrastructure; and move countries closer to achieving the violence-related targets in the 2030 Sustainable Development Goals.
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Global Epidemiology of Induced Abortion
Suzanne O. Bell, Mridula Shankar, and Caroline Moreau
Induced abortion is a common reproductive experience, with more than 73 million abortions occurring each year globally. Worldwide, the annual abortion incidence decreased in the 1990s and the early decades of the 21st century, but this decline has been driven by high-resource settings, whereas abortion rates in low- and middle-resource countries have remained stable. Induced abortion is a very safe procedure when performed according to World Health Organization guidelines; however, legal restrictions, stigma, cost, lack of resources, and poor health system accountability limit the availability, accessibility, and use of quality abortion care services. Even as women’s use of safer self-managed medication abortion options becomes more common in some parts of the world, 45% of all abortions annually are unsafe, nearly all of which occur in low- and middle-resource settings, where unsafe abortion remains a primary cause of maternal death. Beyond country-level legal and health care system factors, significant disparities exist in women’s reliance on unsafe abortion. Even among women who receive a safe abortion, quality of care is often poor. Yet abortion’s precarious status as a health care service and its clandestine practice have precluded a systematic focus on quality monitoring and evaluation of service inputs. Improving abortion and postabortion care quality is essential to meeting this reproductive health need, as are efforts to prevent abortion-related mortality and morbidity more broadly. This requires a three-tier approach: primary prevention to reduce unintended pregnancy, secondary prevention to make abortion procedures safer, and tertiary prevention to reduce the negative sequelae of unsafe abortion procedures. Strategies include two complementary approaches: vulnerability reduction and harm reduction, the first focusing on the root causes of unsafe abortion by addressing the determinants of unwanted pregnancy and clandestine abortion, while the latter addresses the harmful consequences of clandestine abortion. Political commitments to extend service coverage of abortion and postabortion care need to be implemented through actions that build the public health system’s capacity. Beyond the model of receiving care exclusively in clinical settings, models of guided self-managed abortion are expanding the capacity of individuals to take evidence-based actions to terminate their pregnancies safely and without the threat of judgment. Research has strived to keep up with the changes in the abortion care landscape, but there remains a continuing need to improve methodologies to generate robust evidence to identify and address inequities in abortion care and its health consequences in a diversified landscape. Doing so will provide information for stakeholders to take actions toward a new era of health care reforms that repositions abortion as an integral component of sexual and reproductive health care.
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Global Trends in Life Expectancy and Healthy Life Expectancy
Emmanuelle Cambois, Géraldine Duthé, and France Meslé
In the known history of humanity, life expectancy scarcely exceeded 30 years, with half of newborns dying before age five, up to the 18th century. However, from the 18th century onward, major epidemics were combatted more efficiently, famines became less frequent, and life expectancy thus began to increase, first in Northwest Europe, then spreading to North America, Australia, Japan, and to the rest of Europe. The health transition reached Latin America, the rest of Asia, and Africa only in the 20th century.
In 2015–2020, worldwide life expectancy at birth reached 72.5 years. However, differences remained large between regions and countries. The Japanese experienced the highest level at 84.4 years, thanks to their increasingly effective noncommunicable disease (NCD) control and an especially dramatic decrease in cardiovascular mortality. On average, life expectancy was 80.9 years in high income countries, 71.4 in middle income countries and 63.4 in low income countries. It was only 60 years in sub-Saharan Africa, with some countries barely exceeding 50. High mortality countries suffer a heavy burden from both infectious and NCDs.
Due to increasing life expectancy, deaths shifting to older ages, and changing cause-of-death patterns, questions arise concerning the health of populations. The health expectancies made available mainly in high income countries are indicators that combine mortality and health data. Although it seems that severe disability has not increased in the early 21st century, the results for less severe disabilities diverge from one country to the other. Along their longer life expectancy, females live more unhealthy years than males; in some countries they even live fewer healthy years than males.
The future may see life expectancy surpassing 90 years in the most advanced countries, likely before the end of the 21st century. However, achieving this requires that humanity face major challenges, especially in overcoming infectious diseases, impeding NCDs, reducing poverty and socioeconomic inequalities, and combating the deterioration of our environment.
Article
Measuring Mortality Crises: A Tool for Studying Global Health
Stefano Mazzuco
Measuring the impact of a public health crisis in terms of mortality might seem a straightforward method to quantify its effect on the population because deaths are much more easily registered compared to other health outcomes. However, despite the intuitive appeal of this path, it is far from obvious how to best operationalize it, and all the most used methods have drawbacks that should be kept in mind. Especially during the COVID-19 pandemic, the major routes that have been considered are cause-specific death counts (and related measures such as case fatality rates), excess deaths estimates, and life expectancy decline. All the considered approaches have limitations: Cause-specific deaths are often subject to undercount or overcount issues with significant differences both between and within countries, excess deaths estimates may strongly depend on the baseline (there are several methods to estimate it), and life expectancy drop estimates (or estimates of years of life lost) also depend on the reference level used, which can vary substantially across countries. More generally, the issues of available data quality and standardization of age structure should be taken into proper account. Thus, the choice of which approach is worth using depends on the characteristics of the crisis that need to be evaluated and the type and quality of data available. Interestingly, the three approaches can also be combined so that some of their limitations can be mitigated.
Article
Migrant Health in Refugee Camps: A Neglected Public Health Issue
Manuela Valenti
There are 1 billion migrants in the world today, which means that one in seven of the world’s population are migrants. Of these, 272 million are international migrants and 763 million are internal migrants. It is estimated that around 70 million of the world’s migrants, both internal and international, have been forcibly displaced.
Many things force people to leave their homes in search of a better future: war, poverty, persecution, climate change, desertification, urbanization, globalization, inequality, and lack of job prospects. Migrants remain among the most vulnerable members of society even when their living conditions improve after migration.
Migrant women and children are a particularly vulnerable group and have a great need for basic and preventive health care.
Many refugees and migrants are young and in good health, but hard living conditions and difficulty accessing basic health care can affect their state of health. Many of them face inhuman journeys during migration and live in refugee camps with very low standards of hygiene; when they find a job, they are often exploited. All these things can also affect their mental health.
Migrants struggle with similar challenges as other marginalized groups when it comes to access to health care, but they face the additional barriers of mobility, language barriers, cultural differences, lack of familiarity with local health care services, and limited eligibility for publicly and privately funded health care.
Governments should provide affordable preventive and basic health care to refugees and migrants not only because it is a human right but also because in the long term it can lower the costs of the whole health care system.
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Migration and Obesity
Solveig A. Cunningham and Hadewijch Vandenheede
There are over 230 million international migrants worldwide, and this number continues to grow. Migrants tend to have limited access to and knowledge about resources and preventative care in their communities of reception, but nonetheless they are often in better health by many measures compared with native-born people in their communities of reception and with the people they left behind at their place of origin. With time since arrival, however, immigrants’ health advantages often dissipate and they experience increases in health problems, especially obesity and diabetes, which are chronic diseases that are increasingly prevalent in the overall population as well and are associated with multiple co-morbidities and limitations. It may be that immigrants have specific health endowments leading to these health patterns, or that the processes involved in migration, including exposure to new environments, behavioral change, and stress of migration may also affect risks of obesity and other chronic conditions. Understanding the health patterns of migrants can be useful in identifying their specific health needs, as well as contributing to our understanding of how specific environments, changes in environments, and individual health endowments interplay to shape the long-term health of populations.
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Occupational Health Challenges for Immigrant Workers
Emily Q. Ahonen
Occupational health and safety concerns classically encompass conditions and hazards in workplaces which, with sufficient exposure, can lead to injury, distress, illness, or death. The ways in which work is organized and the arrangements under which people are employed have also been linked to worker health. Migrants are people who cross borders away from their usual place of residence, and about one in seven people worldwide is a migrant. Terms like “immigrant” and “emigrant” refer to the direction of that movement relative to the stance of the speaker. Any person who might be classified as a migrant and who works or seeks to work is an immigrant worker and may face challenges to safety, health, and well-being related to the work he or she does. The economic, legal, and social circumstances of migrant workers can place them into employment and working conditions that endanger their safety, health, or well-being. While action in support of migrant worker health must be based on systematic understanding of these individuals’ needs, full understanding the possible dangers to migrant worker health is limited by conceptual and practical challenges to public health surveillance and research about migrant workers. Furthermore, intervention in support of migrant worker health must balance tensions between high-risk and population-based approaches and need to address the broader, structural circumstances that pattern the health-related experiences of migrant workers. Considering the relationships between work and health that include but go beyond workplace hazards and occupational injury, and engaging with the ways in which structural influences act on health through work, are complex endeavors. Without more critically engaging with these issues, however, there is a risk of undermining the effectiveness of efforts to improve the lot of migrant workers by “othering” the workers or by failing to focus on what is causing the occupational safety and health concern in the first place—the characteristics of the work people do. Action in support of migrant workers should therefore aim to ameliorate structural factors that place migrants into disadvantageous conditions while working to improve conditions for all workers.
Article
The Political Determinants of Health: A Global Panacea for Health Inequities
Daniel E. Dawes, Christian M. Amador, and Nelson J. Dunlap
The political determinants of health create the structural conditions and the social drivers—including poor environmental conditions, inadequate transportation, unsafe neighborhoods, poor and unstable housing, and lack of healthy food options—that affect all dynamics involved in health. Globally, recurring examples of the role that these political determinants—through government action or inaction, and policy—are playing in health outcomes and life expectancy, particularly in under-resourced communities, can be observed currently as well as historically. Most notably, the political determinants of health are more than merely separate and distinct from social determinants of health: they serve as the instigators of the social determinants of health with which many people are already well acquainted. They involve the systematic process of structuring relationships, distributing resources, and administering power, operating simultaneously in ways that mutually reinforce or influence one another to shape opportunities that either advance health equity or exacerbate health inequities. Focusing on the political determinants of health homes in on the fundamental causes that give rise to, sustain, and exacerbate the social determinants of health that create and worsen the persistent and devastating health inequities that are observed, experienced, researched, and reported. By employing both a theoretical and practical lens to the amelioration of health inequities that continue to pervade communities across the globe, the article contextualizes many of the historic harms that have occurred throughout history, providing a unique perspective on the current state of affairs, and offering a tangible path forward toward a more equitable future. Furthermore, consideration of this new framework at all levels of government as it relates to improving health outcomes for any nation is imperative in order to eliminate existential threats for any and all populations.
Article
Global Public Health Impact of Vaccines in Children
Peter McIntyre and Tony Walls
From the first vaccine (cowpox, developed by Edward Jenner in 1796), more than 100 years elapsed before additional vaccines for broad population use (diphtheria toxoid, tetanus toxoid, and whole cell pertussis) became available between 1920 and 1940. Then followed inactivated polio vaccine in the 1950s, and live attenuated vaccines for measles, mumps, rubella, and polio in the 1960s. In 1979, global elimination of smallpox was formally certified, with the last human case occurring in Somalia, almost 200 years after Jenner administered cowpox vaccine to James Phipps.
In 2019, global elimination is tantalizingly close for maternal and neonatal tetanus and polio. Despite recent outbreaks, elimination has also been achieved at country and regional levels for measles and rubella and, if achieved globally, will offer, as it has for smallpox, large reductions in child mortality and morbidity and in health system costs. Short of elimination, it is important to define the public health impact of vaccines broadly and at the population level. These broader impacts include benefits to families flowing from prevention of long-term sequelae of infection in children, and to populations and health systems from reduced transmission of infection. Importantly, well-delivered vaccination programs will have a substantial impact by improving equality in health outcomes across populations. Broader impacts include reductions in syndromic disease beyond laboratory-proven infection (e.g., diarrhea and pneumonia), indirect reductions in disease in those not immunized (within and beyond age cohorts targeted by vaccine programs), and improvements in other health services driven by the infrastructure for vaccine delivery. Measurement of these broader impacts can be challenging and must also acknowledge the potential for trade-offs, such as replacement disease due to non-vaccine strains, as documented for pneumococcal infection.
The realization of the benefits of vaccines globally for all children began with the Expanded Program on Immunization (EPI) initiated by the World Health Organization (WHO) in 1974. The EPI focused on improving coverage of six already available but grossly underutilized vaccines—diphtheria–tetanus–pertussis (DTP), polio, measles, and Bacille Calmette–Guerin (BCG). Through the EPI, estimated global coverage for 3 doses of DTP increased from around 20% to over 85%. Subsequent to the EPI, the Global Alliance for Vaccines and Immunization (GAVI), the Global Immunization Vision and Strategy (GIVS), and, most recently, the Global Vaccine Action Plan (GVAP) have aimed to improve access to additional vaccines in the poorest countries. These include Haemophilus influenzae type b (Hib), hepatitis B, pneumococcal conjugate, rotavirus, and human papillomavirus (HPV) vaccines, all introduced in high-income countries from the 1990s. In this chapter, the scope and methodological issues in measuring public health impact are reviewed, and estimates of the global public health impact of individual vaccines in children summarized, concluding with potential future benefits to global child health from expanded maternal vaccination and vaccines under development.
Article
Rebooting Education: A Keystone to Ending Racial and Ethnic Minority Health Disparities
William A. Vega and Esther J. Calzada
Undermining educational attainment at any stage is a threat to life course health. A strong educational platform is required for adequate human development in the 21st century because it provides a foundation for lifelong knowledge, skills, and competencies that protect health. The importance of educational attainment for health has been acknowledged but remains understudied as an interdisciplinary issue. In US American society, unequal educational opportunity is a historical reality and is reflected in health disparities among African American and Latinx populations over the life span. Reform efforts have been initiated for decades, yet gains in educational attainment show limited progress and wide disparities in lifetime health persist. Educational attainment is a fundamental social determinant of health because it leverages higher income, improves the management of other social determinants of health, improves social skills, improves occupational life chances, and extends life expectancy. The reverse is also true. Low educational attainment that is intergenerational imperils human development by failing to prepare youth with the capabilities to overcome structural disadvantages and poverty, which themselves imperil development. African American and Latinx populations in the United States, who together represent nearly 100 million people and who will be the largest component of the majority-minority American population by the year 2046, confront a web of aversive social determinants, including poverty in de facto segregated communities, violence and trauma, toxic exposures, poorly compensated and often temporary employment, a lack of universal health insurance, racism, and sexism in their daily lives. Clearly, there are social, biologic, and psychological issues associated with the educational attainment and health gradient, and early childhood learning experiences represent a critically important opportunity for human potential by advancing cognitive performance, problem-solving ability, motivation to learn, and overall structural and functional brain development. Families from low educational attainment backgrounds experience the negative impacts of social determinants in their daily lives, and their children’s life chances are diminished by poorly funded schools with ineffective educational programs. Putative causes and potential responses to overcoming the historical problem of neglect have been identified, and there are promising efforts at educational system reform aiming to promote health with effective programs and comprehensive strategies that will close the gaps in educational attainment.
Article
Religion, Aging, and Public Health
Jeff Levin and Ellen Idler
Religion, in both its personal and institutional forms, is a significant force influencing the health of populations across the life course. Decades of research have documented that expressions of faith and the practice of spiritual pursuits exhibit significantly protective effects for physical and mental health, psychological well-being, and population rates of morbidity, mortality, and disability. This finding has been observed across sociodemographic categories, across nations and cultures, across specific disease outcomes, and regardless of one’s religious affiliation. A salutary religious effect on health and well-being is especially apparent among older adults, but is also observed across generations and age cohorts. Moreover, this association has been persistently found for various religious indicators, including attendance at worship services, prayer and other private practices, subjective feelings of religiosity, and numerous measures of religious behaviors, attitudes, beliefs, and experiences. Finally, a protective or primary preventive effect of religion has been observed in clinical, epidemiologic, social, and behavioral studies, regardless of research design or methodology.
Faith-based organizations also have contributed to the health of populations, in partnerships or alliances with medical institutions and public health agencies, many of these dating back many decades. Examples include congregational health promotion and disease prevention programs and community-wide interventions, especially targeting the health and well-being of older congregants and those in less well-resourced communities, as well as faith–health partnerships in healthcare delivery, public health policymaking, and legislative advocacy for healthcare reform. Religious denominations and institutions also play a substantial role in global health development throughout the world, individually and in partnership with national health ministries, transnational medical mission organizations, and established nongovernmental agencies. These efforts focus on a wide range of goals and objectives, including building public health infrastructure, addressing ongoing environmental health needs, and responding to acute public health challenges and crises, such as infectious disease outbreaks. Constituencies include at-risk populations and cohorts throughout the life course, and programming ranges from perinatal care to maternal and child healthcare to geriatric medicine.
Article
Social Medicine and the Social Sciences in Latin America: Conceptual Tensions for the Transformation of Public Health in the 20th Century
Arachu Castro
The development of public health in Latin America during the 20th century combined, early on, the social medicine framework on the social, political, and environmental origins of disease with the contributions of medical anthropological fieldwork. Despite the hegemony of the medical model, the surge of the preventive medicine framework further legitimized the involvement of social scientists in the study of the multicausality of disease. However, the limitations brought by the preventive medicine model’s lack of historical and political contextualization gave way to the Latin American social medicine movement, which was grounded in historical materialism, and the development of both critical epidemiology and critical medical anthropology.
Article
Water Safety Plans
Karen Setty and Giuliana Ferrero
Water safety plans (WSPs) represent a holistic risk assessment and management approach covering all steps in the water supply process from the catchment to the consumer. Since 2004, the World Health Organization (WHO) has formally recommended WSPs as a public health intervention to consistently ensure the safety of drinking water. These risk management programs apply to all water supplies in all countries, including small community supplies and large urban systems in both developed and developing settings. As of 2017, more than 90 countries had adopted various permutations of WSPs at different scales, ranging from limited-scale voluntary pilot programs to nationwide implementation mandated by legislative requirements. Tools to support WSP implementation include primary and supplemental manuals in multiple languages, training resources, assessment tools, and some country-specific guidelines and case studies.
Systems employing the WSP approach seek to incrementally improve water quality and security by reducing risks and increasing resilience over time. To maintain WSP effectiveness, water supply managers periodically update WSPs to integrate knowledge about prior, existing, and potential future risks. Effectively implemented WSPs may translate to positive health and other impacts. Impact evaluation has centered on a logic model developed by the Centers for Disease Control and Prevention (CDC) as well as WHO-refined indicators that compare water system performance to pre-WSP baseline conditions. Potential benefits of WSPs include improved cost efficiency, water quality, water conservation, regulatory compliance, operational performance, and disease reduction. Available research shows outcomes vary depending on site-specific context, and challenges remain in using WSPs to achieve lasting improvements in water safety. Future directions for WSP development include strengthening and sustaining capacity-building to achieve consistent application and quality, refining evaluation indicators to better reveal linked outcomes (including economic impacts), and incorporating social equity and climate change readiness.
