Smallpox model might help South Texas understand how to prepare

San Antonio (Dec. 17, 2003) – What would a smallpox epidemic look like? What kind of resources would cities need to effectively respond? Representatives of a San Antonio think tank with a federal grant to develop decision-making tools for public health emergencies spoke at The University of Texas Health Science Center at San Antonio (UTHSC) Dec. 12 about a model they plan to share with the UTHSC, the city of San Antonio and other response agencies.

“It’s important to understand what we are preparing for,” said Harold L. Timboe, M.D., M.P.H., director of the UTHSC Center for Public Health Preparedness and Biomedical Research, which sponsored the lecture. “When we prepare for battle, we hold war simulations to anticipate every contingency. We need to do the same for something like smallpox in this country, to understand how it might spread in a large metropolitan area under the various scenarios in which it could be released and so that we have a reasonable estimate of the number of patients for whom we might have to provide care.”

Dan Gower, Ph.D., a senior analyst with Altarum, a non-profit research and innovation institution with offices in San Antonio, discussed current development of a readiness tool kit to help emergency planners. He presented information on the Healthcare Complex Model, which simulates health care delivery at the patient episode level throughout a network of facilities. The model explores the impact of changes on patient outcomes and resource usage.

“The answers we get will not solve the problem, but they will describe the magnitude of the problem we might face,” he said. Smallpox is a communicable disease that was eradicated worldwide after 1950. No cases have been reported in the United States in about 50 years. Although most adults over age 30 have been vaccinated against smallpox, much of their immunity has declined over the years, he said.

Altarum has a grant from the U.S. Agency for Healthcare Research and Quality (AHRQ) to study potential responses to bioterrorist attacks. During the grant’s first year, Altarum created a simulated outbreak of plague in a rural setting (Smithville, Texas). The simulation in this relatively small population compared outcomes based on an average level of preparedness and a high level of preparedness. At the average level of preparedness, 12 lives were saved using the antibiotic ciprofloxacin. At high preparedness, 35 lives were saved in the model.

In year two of the AHRQ grant, Altarum will create a model of smallpox in the nation’s ninth-largest city, San Antonio. Assumptions used in the models are developed from interviews with infectious disease physicians, epidemiologists and other experts, Dr. Gower said.

Factors affecting the study to be conducted involve the public health response and the manner in which the health care system could “surge” to handle the added workload. The spread of the disease through the community would be affected by how many people are infected prior to recognition of a smallpox outbreak, how many have been vaccinated and when, policies for transferring patients between health care facilities, the availability of providers and resources, and the “worried well,” healthy individuals who because of their concern about the outbreak might tie up health care assets needed for the acutely ill. All of these are represented in the Healthcare Complex Model.

Dr. Timboe is commander of the Texas Medical Rangers, a Texas State Guard volunteer medical reserve corps based at the UTHSC. Gov. Rick Perry selected the Health Science Center to be the first site in Texas for such a medical reserve unit. “The Texas Medical Rangers group represents an auxiliary workforce that could be brought to bear when an act of bioterrorism has occurred and the health care system has been overwhelmed,” Dr. Gower said.

A year ago San Antonio emergency planners held a smallpox exercise called Pale Horse. It simulated response to a supposed smallpox release in the Alamodome, causing 20,000 spectators to be exposed and prompting many to seek treatment at area hospitals. The exercise simulated establishment of smallpox vaccination clinics across the city. “It was a good start to make our responsible officials understand the types of problems we would face if smallpox unexpectedly came back to San Antonio and to set the stage for follow-up planning, training and exercises,” Dr. Timboe said. “We must keep refining our response mechanisms – preparedness does make a difference. The people of San Antonio and South Texas should expect this of us.”

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