The threat of airborne anthrax adds urgency to antibiotic stockpile plans

A public health crisis unlike any we ever have faced’ 

The threat of airborne anthrax — the new clear and present danger in the realm of bioterrorism — is spurring public health officials to underscore the importance for states and communities to plan ahead for dispensing mass quantities of antibiotics.

A chilling new threat assessment of anthrax was described during a recent satellite training broadcast on rapid distribution of the federal Strategic National Stockpile (SNS) of antibiotics and other critical medicines.

"Recent threat analyses have made it clear that many of us have been underestimating the size of the threat associated with outdoor release of spores of Bacillus anthracis — the organism that causes anthrax," said William Raub, PhD, principal deputy assistant secretary of public health emergency preparedness at the U.S. Department of Health and Human Services (HHS). "We now realize that using only conventional microbiological techniques and commercially available spraying equipment, terrorists could distribute Bacillus anthracis spores over an area of several square miles. If those several square miles correspond to a densely populated area, we would have a public health crisis unlike any we ever have faced."

Raub’s warning that terrorists could disperse airborne anthrax over an unsuspecting population with frightening ease follows dire assessments by other officials. For example, Michael Osterholm, PhD, an advisor to HHS Secretary Tommy Thompson, noted that there were 250 million infectious doses in each anthrax envelope that was sent in 2001. Yet as powerful as it was, the anthrax apparently was not the work of a highly skilled bioweapons laboratorian.

The FBI "reverse engineered" the anthrax powder used in the attacks and found it was made by somebody who probably had no more than a college education and spent less than $5,000 using off-the-shelf technology, according to Osterholm.

The common theme of these risk assessments appears to be that little sophistication is required for either production or dispersal of airborne anthrax. The key to meeting the anthrax threat in medical terms is outbreak detection and rapid distribution of antibiotics. Whether you live in Maine or Hawaii, the Centers for Disease Control and Prevention (CDC) said it has a "push package" of ciprofloxacin and other drugs that will be there within 12 hours after an attack is detected. The push packages are caches of pharmaceuticals, antidotes, and medical supplies designed to provide rapid delivery of a broad spectrum of assets for anthrax or an undefined threat in the early hours of an event. The packages are positioned in strategically located, secure warehouses ready for immediate deployment.

"[After an attack], the biggest remaining hurdle is to get pills from the airport into people’s mouths in time to save lives," Raub said. "We would know that among those who inhaled enough spores, the first cases of pulmonary anthrax almost certainly would appear within 48 hours. We, therefore, would have to initiate chemoprophylaxis for everyone in the affected geographic area within as short a period of time as possible. . . . Simply put, the longer we take to distribute the antibiotics the more people will die. If the affected area includes a million or more people, each day’s delay in penetrating the community with antibiotics could translate into thousands if not tens of thousands of deaths," he added.

Rolling out the stockpile

The decision to roll out the SNS may be based on evidence showing the overt release of an agent, but more likely more subtle indicators such as patterns of unusual morbidity and mortality will trigger it. To receive SNS assets, the affected state’s governor’s office will directly request the deployment of the SNS assets from the CDC or HHS.

"Mass antibiotic dispensing is where the rubber meets the road during a bioterrorism attack," said Curtis Mast, MS, SNS, exercise coordinator at the CDC. "All other emergency plans may work flawlessly, but if a community cannot rapidly dispense medications to its population, lives may be lost. While many of us are familiar with dispensing clinics, this scenario will be different because of the quick ramp-up time required and the almost overwhelming number of people that will require medication."

To accomplish the basic goal of getting "pills in people" following an anthrax attack, for example, state and local planners must predetermine their points of dispensing or PODs. One of the best sources of information on setting up POD sites is Weill Medical College of Cornell University in New York City. POD researchers there have developed a Bioterrorism Epidemic Response Model (BERM), which can help planners determine staffing needs and ways to avoid patient bottlenecks at antibiotic distribution sites. (For information on BERM, go to www.ahrq.gov/research/biomodel.htm.)

"If you’re in a situation where there has been a covert or hidden release of an anthrax agent and people are starting to become ill, you may need to move a truly unprecedented amount of antibiotics into the public’s hands in record time," said Nathaniel Hupert, MD, MPH, one of the principals in the BERM program at Cornell. "It is a good strategy to think about what would be for the most extreme situations and then [work] backward to more easily managed scenarios."

The BERM model was essential in helping planners in Minnesota, said Luane McNichols, BSN, MN, clinical coordinator at the state department of health in Minneapolis.

"We found that deciding on the number of PODs was a huge challenge," she explained. "The BERM model enabled us to manipulate variables to look at multiple scenarios for mass dispensing. It also helps the regions look at their available staff, population, and facilities and make a judgment about how large their dispensing sites should be in terms of throughput or persons per hour."

POD sites selected in Minnesota include schools, conference centers, and churches with throughputs ranging from 250 patients per hour to 1,000 per hour, she noted. Implementing the state smallpox immunization program previously helped establish regional contacts that made the POD planning go easier, McNichols added. The state has regional and local interdisciplinary teams that include representatives from public health, hospitals, emergency management, Native American tribal members, and volunteer groups.

Concerning the latter, the issue of volunteers is a formidable one every community has to face in planning to meet the challenge of mass distribution of antibiotics. "After all of the structure is in place, we are left with a really huge challenge: finding the people, filling the positions with the appropriate people, and of course, getting them trained," McNichols explained. "This is an almost overwhelming task."

Experts dealing with volunteer groups say it is not so much a question of whether people will step forward in an emergency — they will — but how to assign them tasks and duties that can make for a smooth operation. One idea is to give volunteers consistent, defined roles in all PODs, McNichols said. "Volunteer recruitment is being planned through a statewide registry, and a number of the counties have a medical reserve crop, or they are looking at forming them. We realize that many PODs will still have staffing gaps. It is our hope that volunteers will come forward in an event and then be just-in-time trained on- or off-site."

Borders will not be respected

To ease dispensing, the state plans call for standing prescription orders that will be written by the state epidemiologist. The state has been divided into eight regions in terms of planning, but, of course, disease does not respect borders.

"All of them are aware that an event will cross all borders, so we are actively planning across the regions, with neighboring states and with Canada on all cross-border issues," McNichols said. "As the regions are picking their POD sites, they are projecting where their populations will go in an event based on normal traffic patterns and normal habits. As we work with a neighboring state we realize that populations are often more apt to go a bordering city that’s nearby rather somewhere further away in their own state."

Using population density data and the BERM model, Minnesota planners have figured out how to place the PODs where only 15% of the population will have to drive more than five miles to reach a site in urban areas, she pointed out.

In the states’ vast rural areas each region had to make a reasonable commute decision for their population, with some deciding on one, two hours, or even longer, she says. "Some have chosen to set up traveling dispensing units," added McNichols.

Indeed, given the complex issues raised by establishing PODs, federal planners are looking at novel ways to augment the process.

In addition to mobile dispensing units, another strategy under discussion with the U.S. Postal Service is to have mail carriers deliver antibiotics to residential addresses. While these efforts may augment the process, PODs still will have to be established and run by local health responders and volunteers. "The primary initial burden falls entirely on the local community," Raub said.

Common problems and questions are expected to arise regardless of the region. For example, what do you do with the worried well, those patients who do not meet the exposure definition but nevertheless demand antibiotics at the POD site.

"They are going to show up; what do you do with them?" Mast asked. "Do you turn them away because they don’t meet the exposure profile? You’ll have to have a response and an information packet for the worried well. Your response may be as simple as, We understand your concern. You don’t need the criteria for exposure that the health officer defined; and because of that, you’re not going to get medication today. But here is a packet of information that includes a phone number and web site where you can receive more information."

Such issues underscore the importance of adequate security and a public education campaign through the local media. "Providing information and medication go hand in hand, he added. "You will not have a successful [distribution effort without] a media, public relations, risk communications campaign."

An initial priority is that all key local players — and their families — are given antibiotics or other medicine first as warranted by the bioterrorism agent, he said.

(Editor’s note: For more information about the public health satellite training broadcast described in this story, go to www.phppo.cdc.gov/phtn/antibiotic.)