From Genes to Public Health: The Journey Continues! Open Access

At the end of 2024, I retired from the Centers for Disease Control and Prevention (CDC) after a 40-year career in public health. For the past 26 years, I led the Office of Public Health Genomics (PHG), which was formed in 1998. During my career, I was lucky to witness and contribute to the development of three fields: genetic epidemiology, PHG, and precision public health (PPH). Together, these fields are increasingly crucial in realizing the population health benefits of genome discoveries and other new technologies. But we are still in the early days on the trajectory from genes to public health. With many global challenges ahead, the next 40 years are going to be more exciting than the last 40 years in applying these fields to emerging validated tests and interventions that can save lives, prevent disease, and reduce health inequities. Many of the advances in genomics translation and implementation could be unraveled because of government budget cuts in science and public health. Herein, I offer a brief perspective on the evolution and contributions of these fields to medicine and public health and offer some recommendations to increase their population health impact.

Since the 1970s, genetic epidemiology has been a well-established field at the intersection of genetics and epidemiology and is concerned with the study of the role of genetic factors in the occurrence of disease in populations [1]. A main emphasis of genetic epidemiology has been on the study of familial aggregation of various diseases and on statistical methods for gene discovery. Applications of genetic epidemiology have led to successful identification of thousands of genes associated with Mendelian disorders and high-penetrance genetic variants associated with birth defects, cancer, heart disease, and other common diseases.

After the completion of the Human Genome Project, genetic epidemiology has broadened its approach to population-based studies of numerous genetic variants. Advances in genomics have accelerated discovery efforts using genome-wide association studies and genome sequencing studies, which now make possible the evaluation of numerous gene associations and interactions. To capture new developments in the field, the term “human genome epidemiology” has been increasingly used to further elaborate on epidemiologic approaches to conduct studies not only in convenient samples or selected groups but in well-defined and increasingly representative populations (such as whole countries, states, health systems, etc.) on the continuum from gene discovery to applications in medicine and public health [2]. An expansion of the epidemiologic approach is increasingly occurring to better understand and characterize the health effects of genetic factors and their interactions with the environment in diverse populations. This includes assessing the prevalence of genetic factors in well-defined populations, estimating risks of various health outcomes, and investigating gene-environment interactions [2].

In 1998, the CDC and other organizations in the USA and other countries began addressing the public health implications of new human genome discoveries [3]. This was the beginning of the PHG movement worldwide. This journal has been an important destination for sharing research findings, ideas, and dialog about PHG. A main goal of PHG was to identify, evaluate, and integrate evidence-based genomics applications into public health programs that prevent and control leading causes of morbidity and mortality. As outlined by the Institute of Medicine decades ago [4], many groups and organizations (such as healthcare and community-based organizations, academic and research institutions, advocacy groups, and the private sector) conduct research and develop programs that can improve population health. Nevertheless, government agencies (federal, state, and local) are considered the backbone of the public health system (often referred to as “public health”) [4].

Before the Human Genome Project, public health focused on only a handful of genetic applications. Newborn screening is often considered as the foundation of genetics in public health and a great public health achievement. By 2024, multiple human genomic applications have entered healthcare across the lifespan. These include, among others, expanded carrier testing, noninvasive prenatal testing, expanded newborn screening using genomic technologies, genetic testing of sick infants, and genetic testing of children with birth defects and developmental disorders. In addition, genomic applications have been introduced for diagnosis, screening, and prediction of an increasing number of adult conditions, such as cancer and heart disease.

An important area of PHG under current exploration is genomic screening beyond the newborn period [5]. Using the rationale of newborn screening programs, a new partnership is being developed between the genomics and the public health communities to expand DNA-based screening to adults to identify people with individually rare pathogenic variants but in aggregate, affecting 1–2% of persons in the population. Screening can be based on measuring a defined set of genes that meet the evidentiary bars of high disease risk and effective intervention (e.g., hereditary breast and ovarian cancer and familial hypecholesterolemia) [5]. To date, pilot studies continue to evaluate the validity, utility, economics, and ethics of DNA-based population screening.

To help prioritize data for action in PHG, a simple evidence-based classification framework was developed by CDC for organizing public health action to maximize population level impact [6]. Tier 1 genomic applications are supported by evidence-based guidelines, to reduce morbidity and mortality if implemented effectively. Today, tier 1 genomic applications have the potential to prevent and treat disease in millions of people across the lifespan. Examples of tier 1 genomic applications and their population impact are shown in Table 1 [7‒10].

For example, a tier 1 genomic application is genetic testing for pathogenic variants in BRCA genes, to identify women at increased risk for hereditary breast and ovarian cancer who could benefit from preventive interventions. To track trends and gaps in implementation, we have conducted a number of population level assessments. In one study [11], a CDC study assessed trends in BRCA testing and costs from 2003 to 2014 for women aged 18–64 years using private claims data and publicly reported revenues. The rate of any BRCA testing among women increased by 57% in 2013, compared with average annual increases of 11% in the 3 preceding years. We have also shown lower BRCA testing rates in nonmetropolitan areas than in metropolitan area [12]. The lower rates of testing in rural areas may reflect differences in access to specialty care providers, including cancer genetic service providers. These data were used as part of the development of national and state-based cancer genomics education and surveillance program to increase the implementation of BRCA testing in various subpopulations.

More generally, published studies have consistently shown suboptimal implementation for selected tier 1 genomic applications, leading to uneven uptake among racial and ethnic minority groups, rural communities, uninsured or underinsured people, and those with lower education and income [13]. Addressing health equity in the implementation of genomic medicine is an essential public health imperative [13].

Ultimately, PHG programs are firmly rooted in the three public health functions, assessment, policy development, and assurance, which include the 10 essential public health services [14]. Public health action is accomplished by many organizations and institutions that work together to protect and improve the health of populations. A 2022 CDC strategic plan conducted at the height of the COVID-19 pandemic summarized a framework based on the essential public health services to help reduce disparities in the implementation of genomics. This framework lays the groundwork for identification of goals and measurable outcomes in specific community-based interventions in the next decade [13].

Table 2 shows examples of multiple public health initiatives showing the integration of human genomics across the 10 essential services across the lifespan [15‒19]. To ensure that genomics can be used ethically and effectively to improve population health, activities are based on scientific evidence of validity and utility. PHG will increasingly rely on multiple public health sciences such as behavioral and communication research, community engagement research, ethical, legal, and social implications research, as well as to ramp up implementation science in developing, evaluating, and updating practice and programs.

Ongoing advances in genomics and other “omics,” big data, artificial intelligence, and other technologies have led to a next-generation precision medicine (PM) [20] and PPH [14]. PM refers to increasing personalization of disease diagnosis, treatment, and prevention based on genomics and other technologies. While PM can be viewed as delivering the right intervention to the right patient at the right time, its implementation in today’s health system could leave a lot of people behind. Thus, an important public health role is to ensure that everyone can benefit from advances in PM through organized population programs (e.g., newborn screening), policies, and implementation strategies. PPH is about providing the right intervention to the right population at the right time, with the goal of providing health benefits for all, and considering all determinants of health [21].

Nevertheless, PPH represents much more than the equitable implementation of PM in populations. New technologies can provide more “precision,” beyond human genes, in public health assessment by persons, place, and time [22]. For analysis of persons, public health can now use information beyond traditional demographic indicators such as age, sex, and race/ethnicity integrating new omic data that can help stratify disease outcomes and susceptibility into population subgroups reflecting underlying heterogeneity and potential response to interventions. For example, population-based cancer registries are beginning to use more precise diagnostic classification of cancers (eg, gene expression profiles, proteomic markers, etc.).

For analysis of place, increased data availability and new computational methods allow for more precise geocoding of health-related outcomes on a granular scale, enabling identification of specific regions that might benefit from implementation of targeted interventions [23]. For analysis of time, the use of linked electronic health records can allow for longitudinal tracking clinical and laboratory variables along the natural history of specific health conditions. In addition, smartphone apps can be used for precision screening with symptoms checkers allowing users to understand disease and make informed health decisions and public health to track pooled events over time. During the COVID-19 pandemic, wearable sensors were explored as a means to detect and monitor physiological indicators associated with COVID-19 infection, such as heart rate and respiration rate.

Perhaps the lowest hanging fruit for PPH is the area of pathogen genomics [24]. Advances in DNA sequencing technology have led to the use of pathogen genomics in enhancing PPH through more effective investigations of outbreaks of foodborne illnesses, tuberculosis control, and timely influenza surveillance to inform vaccine selection. The momentum of pathogen genomics in public health accelerated during the COVID-19 pandemic. Genomics and other big data technologies were used in understanding and tracking the outbreak [23] and rapidly developing and applying targeted interventions. SARS-CoV-2 sequences have been used to stratify the viral pathogen into variants. This allowed public health agencies to monitor changes in important characteristics, such as transmissibility, virulence, or immune response, and to respond accordingly based on these changes.

Rapid developments in genomics, big data, and AI have accelerated progress in human genome epidemiology, PHG, and PPH. New technologies are fundamentally changing epidemiologic studies and essential public health services by promoting more rapid and precise response to health threats. The COVID-19 pandemic provided a challenge and an opportunity for deploying new technologies in surveillance and the development of vaccines and therapeutics. The pandemic also led to implementation of data modernization in public health and the increasing use of AI/ML and predictive analytic approaches.

As almost all human diseases have both genetic and environmental risk factors, most epidemiologic studies in the 21st century will benefit from integrating genetic and environmental factors in their design. Genetic epidemiology needs to continue to evolve from a boutique field studying genetic causes of human diseases to a more foundational contributor to population studies of human traits and diseases across the lifespan. Epidemiological data from large studies and biobanks (eg, the All of Us Research Program) will be crucial in translating discoveries into population health impact.

Moreover, additional progress in PHG and PPH will require continued commitment and government funding to enhance data collection, sharing, and analysis across geographic jurisdictions and evaluation of different types of data for their ability to predict and improve health outcomes. Moving forward, this journal will continue to provide a leadership role in future directions of PHG, as well as spotlight the emerging breadth and depth of research and practice in the field. At the same time, advances in other areas of PPH will eventually influence the direction and richness of the research agenda in PHG, and potentially impact the development of PHG policies and programs. The journal’s recent article collection on future forecasting in PHG [25] reflects the growth and development of the field and is a worthwhile reading for anyone interested in the ongoing journey from genes to public health.

The author acknowledges the past and current collaboration of many individuals from within CDC, multiple universities and organizations, and many collaborators from around the world who have collectively shaped these fields over time. Perhaps most importantly, I want to thank the next generation of leaders in public health genomics and precision public health who will continue the next segment of the journey from genes to public health. Since the paper was accepted for publication, the CDC Office of Public Health Genomics was eliminated on April 1, 2025 as part of a large downsizing in programs and reduction in force in the US Department of Health and Human Services. In spite of this temporary setback, I am optimistic that the journey from genes to public health will indeed continue!

The author has no conflicts of interest relevant to this paper. M.J.K. was a member of the journal’s Editorial Board at the time of submission.

The author reports no funding relevant to this paper.

M.J.K. is the sole author of this perspective piece and is responsible for planning and writing it.