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Montgomery County's Public Health Service uses operations research to plan emergency mass dispensing and vaccination clinics.

Article Excerpt
To curb outbreaks of contagious diseases, county health departments must set up and operate clinics to dispense medications and vaccines. Carefully planning these clinics in advance of such an event is difficult and important. We developed and implemented operations research models to improve clinic planning for the Montgomery County (Maryland) Public Health Services. They include discrete-event simulation models and capacity-planning and queueing-system models. We validated these models using data that we collected during full-scale simulations of disease outbreaks. We also developed guidelines for the physical design of clinics based on general queueing principles and our own experiences.

Key words: health care: treatment; simulation: applications.

History: This paper was refereed.

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The threat of an outbreak of contagious disease in the United States, caused by a terrorist act or a natural occurrence, has prompted public health departments to update and enhance their plans for responding to such events. Especially in regions that are densely populated or strategically important, such as the nation's capital, public health officials must plan for potential disasters. In the worst-case scenario, terrorists could release a lethal virus, such as smallpox, into the general population. If this were to happen, every person in the affected area would have to be vaccinated within a few days. For example, Montgomery County, Maryland, would need to vaccinate nearly one million people. To vaccinate so many people in a short period, it would have to set up mass-vaccination clinics at designated sites throughout the county. Kaplan et al. (2002) compare vaccination policies for responding to a smallpox attack and show that mass vaccination results in many fewer deaths than other tactics in the most likely attack scenarios. The spread of a pandemic flu could also trigger mass vaccinations.

Carefully planning mass-dispensing and vaccination clinics (or points of dispensing (PODs)) is important. The health department must train the right number of people beforehand (although they can do some training at the time of need), and must assign the right number of workers to various roles when the clinic begins operations. They must consider the capacity of each clinic (the number of residents it can serve per hour) and the number of minutes residents would spend in the clinic (the time in system, the flow time, or the throughput time). Clinic capacity affects the number of clinics needed and the total time needed to vaccinate the affected population. The time in system affects the number of residents who would be inside the clinic waiting for treatment; too many residents in the clinic can cause crowding and confusion.

The Centers for Disease Control and Prevention (CDC) (2002) have created guidelines to help county health departments plan their responses to such incidents. The guidelines provide some estimates of the time needed to perform such activities and, based on these estimates, suggest the number of staff needed to meet a specific throughput target (118,000 residents per day in Montgomery County). One purpose of our research was to acquire further data about realistic processing times and to assess the adequacy of the existing guidelines.

Clinic capacity and time in system are not the only concerns in planning such clinics. Based on mass-prophylaxis operations in 2001, Blank et al. (2003) described practical concerns that arise in planning and operating mass-dispensing and vaccination clinics, issues (including the incident command system) similar to those faced by managers preparing for other health-care emergency situations (Gardner 1999).

Researchers have used simulation modeling to model health-care systems, such as medical centers, hospitals, and clinical practices (Ledlow and Bradshaw 1999, Merkle 2002, Prieditis et al. 2005, Swisher and Jacobson 2002, Su et al. 2005). Other formal techniques have been applied as well: Malakooti (2004) used a cell-formation approach to design emergency rooms, and Jain and McLean (2004) describe a framework for linking simulation models of disasters.

We developed discrete-event simulation models and capacity-planning and queueing-system models to improve clinic planning in an ongoing collaboration between the University of Maryland, College Park, and the Montgomery County Public Health Services (PHS).

Planning Mass-Dispensing and Vaccination Clinics

Prior to September 11, 2001, Montgomery County, Maryland, had no plans for mass-dispensing and vaccination clinics. PHS, a division of the county's health and human services department, conducted small-scale clinics for county residents, for example, to administer flu vaccine or conduct tuberculosis screening. The importance of mass-dispensing became clear after the anthrax attacks in October 2001. PHS dispensed oral medications through mass-dispensing clinics to postal workers and others who may have been exposed to anthrax. These clinics were quite small (treating about 1,400 residents) and were easy to manage based on the county's previous experience with flu vaccination clinics. In 2002, the CDC began requiring public health departments to develop smallpox vaccination plans. PHS developed those plans to meet CDC and state guidelines. The CDC implemented guidelines for operating dispensing and vaccination clinics, which allowed PHS to enhance their clinic plans. In addition, the county added operational detail to its plans to achieve the Public Health Ready designation defined by the National Association of County and City Health Officials (NACCHO). For a site to earn Public Health Ready status, it must meet goals in three areas: emergency preparedness and response planning, workforce competency development, and exercise simulations (NACCHO 2005b). NACCHO evaluators look for...