A Look at a Critical Player in Public Health, Disease Intervention Specialists

April 13, 2023 | Chris Taylor

For decades, public health disease intervention specialists (DIS) have been critical to public health. Charged with responding to communicable disease outbreaks, such as sexually transmitted infections (STIs), vaccine-preventable diseases, foodborne illnesses, and emergency responses, DIS play an important role in outbreak response.

As multidisciplinary professionals, DIS possess a high level of skill in communicating with individuals and communities with cultural humility, respect, and compassion. DIS are often the face of public health within the communities they serve.

After decades of underinvestment, health departments received increased funding for disease intervention services in 2021, strengthening the existing workforce and providing opportunities to expand workforce capacity. The unprecedented scale-up of public health during the COVID-19 pandemic brought staff to public health who may not have previously been in the workforce. Many of the new staff represented communities most impacted by top public health challenges, achieving longstanding goals of ensuring the public health workforce was diverse and reflected the lived experiences of the communities they served.

A Brief History of Public Health Disease Investigation

In the mid-nineteenth century, British physician John Snow employed some of the same disease investigation strategies still in use today to determine the cause of a cholera outbreak in a London neighborhood. By interviewing people sickened by cholera, Snow pieced together the epidemiological puzzle and determined that contaminated well water was causing the illness. To stop the spread of the disease, he famously removed the handle from the water pump.

In the mid-1900s, the modern role of DIS began to take the form of responding to syphilis and addressing the need for contact tracing and partner notification. The U.S. Public Health Service and state and local health departments employed disease investigators to speak with people who tested positive for syphilis to determine how they were exposed and to whom they may have passed the infection. The investigators also ensured patients received adequate treatment and notified sexual partners about possible exposure. It is important to note, however, that there have been times when not everyone received equal access to care. Between 1932 and 1972, the U.S. Public Health Service engaged in the unethical Syphilis Study at Tuskegee to observe the natural history of untreated syphilis.

Since these early days of STI disease investigation, public health programs have evolved to respond to additional infectious disease threats, including gonorrhea, chlamydia, HIV, and, most recently, COVID-19 and mpox.

Paving the Way for a Response to COVID-19

During the earliest days of the COVID-19 pandemic, DIS assisted communicable disease investigators, public health nurses, and epidemiologists in responding to cases of the novel coronavirus. DIS disease investigations expertise and skills were employed in COVID-19 case investigation and contact tracing. When the outbreak reached pandemic levels, public health capacity was unable to adequately respond to community spread. To rapidly scale up the public health workforce, health departments needed to train a disease investigation and contact tracing workforce.

Existing training courses focused on STIs and HIV and educated DIS in client-centered counseling, motivational interviewing, and risk reduction counseling. The trainings also provided basic information and standard operating procedures for responding to various communicable diseases. However, no educational information, training materials, or platforms combined basic information on the newly identified COVID-19 with the skills needed to conduct rapid response contact tracing services.

In the early days of the pandemic, ASTHO understood the need for COVID-19-specific training for the public health workforce. In partnership with the National Coalition of STD Directors, ASTHO developed Making Contact: A Training for COVID-19 Case Investigators and Contact Tracers, which quickly became a staple training step for health department staff responding to COVID-19. To date, more than 100,000 people have completed the course.

How DIS Evolved to Meet the Challenges of COVID-19

With the growing use of social media and social networking GIS-based apps over the last two decades, the skillset of DIS has evolved to meet people where they are. Historically, DIS have conducted most of their job through fieldwork; during COVID-19, public health investigators conducted most disease investigations by phone. The flexibility and adaptability of DIS benefited the COVID-19 response as trainings evolved to consider alternative communication strategies, including reaching individuals over the phone, through email, and on social networking sites.

Similarly, workplaces changed during COVID-19, with staff working remotely and often communicating via phone or video conference rather than in person and onsite. To address some of these changes in workplace environments due to the COVID-19 response, ASTHO developed a training for DIS supervisors that prepares new and existing supervisors for their roles within governmental public health agencies, building on core management and leadership competencies.

Investments in the DIS Workforce

After decades of underfunding, health departments received a historic investment to support DIS capacity through the American Rescue Plan Act of 2021. The DIS Workforce Development Funding is a $1 billion investment over five years. It intends to support 21st-century outbreak response needs by expanding and enhancing frontline public health staff, conducting DIS workforce training and skills building, building organizational capacity for outbreak response, and evaluating and improving recruitment, training, and outbreak response efforts.

CDC collects evaluation data from health departments on the implementation of the DIS workforce development funding. CDC data indicate that 78% of the STD/HIV health department workforce are or have been deployed in the COVID-19 emergency response. Similarly, case investigation strategies, tools, and workflows, refined over decades of traditional DIS work, were adopted to meet the needs of COVID-19 investigation and contact tracing—data through mid-2022 highlights successes and challenges.

Many health departments have turned to hiring COVID-19 case investigators into broader DIS roles to meet their jurisdiction’s communicable disease investigation needs. As COVID-19 contact tracing activities ramped down, health departments were able to redirect some COVID-19 staff into other public health vacancies or new positions.

Resources for Expanding the DIS Workforce

Several barriers exist around hiring new DIS staff. Government hiring systems can make it challenging to create new full-time equivalent positions, and many jurisdictions had hiring freezes in place at the start of COVID-19. While the American Rescue Plan Act made significant federal funding available for five years, government systems may be reticent to hire staff if consistent funding is not anticipated past the funding cycle, which would result in position elimination and staff layoffs.

DIS Workforce Expansion Funding evaluation data indicate that barriers and challenges faced by health departments include complex and lengthy hiring processes within government systems, limited capacity and overburdened human resources staff and systems, recruitment challenges due to low salaries and low unemployment, and increased staff turnover resulting in more vacant positions and limited capacity.

Health departments seeking to promote job opportunities should consider PublicHealthCareers.org, a website managed by ASTHO where health departments can post available job openings. Several resources also assist potential applicants in their public health careers.

The National Coalitions of STD Directors has created useful tools to assist health department staff with implementing the workforce expansion grant, including:

• DIS Funding Barriers and Ideas
• Recruitment and Hiring—Health Equity
• Interviewing DIS applicants—Equitable Hiring
• Using Informatics to Improve Connections Between People and Systems

As health departments continue to build and expand DIS workforce capacity, we’d like to hear about your successes and challenges. Please let us know by emailing Chris Taylor, ASTHO director of infectious disease outbreak response and recovery.