Hospitals heed warning signs of avian influenza pandemic
Time to stockpile antivirals and set vaccine priorities
As avian influenza cases continue to emerge in Vietnam, the call for pandemic preparedness is gaining urgency. Between mid-December and mid-March, there have been 24 human infections of influenza A (H5N1) in Vietnam — 13 of them fatal. Public health experts caution the virus could mutate and become transmissible among people — the key to a pandemic.
A pandemic is like a 100-year storm: No one knows when one will occur, but it is certain to come eventually, public health authorities say. Hospitals need specific contingencies for dealing with pandemic influenza, along with their general emergency preparedness plans, says Ben Schwartz, MD, senior science adviser in the National Vaccine Program Office.
Based on the pandemics of 1957 and 1968, researchers estimate that the next pandemic could attack up to 35% of the population, causing about 750,000 hospitalizations and more than 200,000 deaths. A pandemic similar to the one in 1918, which caused more than 500,000 deaths, would be catastrophic.1
As a potential for a pandemic, H5N1 avian influenza is of particular concern. Cases have been concentrated in otherwise healthy children and young adults. It has a high mortality rate; of 69 confirmed cases, there were 46 deaths. Outbreaks among poultry have occurred in five Asian countries, and the virus has been found in wild waterfowl and domestic ducks as well as other mammals.
"No one knows whether the present window of opportunity to intensify preparedness will remain open or close abruptly," stated a World Health Organization report.2 "Experts readily agree, however, that H5N1 has demonstrated considerable pandemic potential. With the virus now endemic, the probability that this potential will be realized has increased."
As hospitals consider their priorities, protection of health care workers will be at the forefront, Schwartz notes.
"There are three things that will protect a health care worker in a pandemic: vaccination, antivirals, and infection control," he says.
Each state is required to submit a preparedness plan by the end of the year, and the Health Resources and Services Administration (HRSA) has given money to state health departments for pandemic preparedness.
Here are some issues to keep in mind as you prepare for pandemic influenza:
• Decide whom to vaccinate.
"We view vaccination as likely the most important activity to decrease morbidity and mortality; but the vaccine will not be available immediately, and supply will be limited." Schwartz says.
Hospital plans should outline who would be the first to receive a vaccine. But keep in mind, vaccine development may be difficult. After all, there is only one manufacturer with domestic production, he notes. And it takes time to produce the first vaccines.
"The first doses may become available about four months after a reference strain becomes available," Schwartz says. "Two doses will be needed for protection."
There are about 11 million health care workers, including 5 million in hospitals and 6 million in outpatient facilities, he explains. "Just to vaccinate the nation’s health care workers would take the entire first month of the supply of the vaccine."
The bottom line: Set priorities for your most essential workers who would be the first to receive the vaccine.
• Consider stockpiling antivirals.
With vaccine supply limited or delayed, the first line of defense against pandemic influenza may be antiviral medications. But again, there won’t be enough. Who should get them?
Prophylaxis for 11 million health care workers would require 61.6 million doses. Even treating influenza illness among that population would require 3.9 million doses, Schwartz says.
The U.S. government stockpile contains 2.3 million doses of oseltamivir (Tamiflu), a neuraminidase inhibitor that is considered more effective and less susceptible to resistance than older versions of antivirals.3
Prophylactic use of antivirals can be quite effective in preventing spread of the disease, explains Frederick Hayden, MD, professor of internal medicine at the University of Virginia Health Sciences Center in Charlottesville.
"We know that from the study of drugs in past pandemics, we can protect against influenza," he adds.
"That means daily drug during the period of risk, which in a pandemic may be an eight-week period. That means you’re going to be giving prophylaxis to a lot of people for a sustained period of time," Hayden says.
If sufficient antivirals are not available, hospitals may want to give antivirals to health care workers soon after diagnosis to limit their disease, he adds.
"If you can treat within the first day and a half or so of illness, you can get up to three days benefit in terms of rapid functional recovery," Hayden explains. "I think that’s important for health care workers to get them back on the job."
Oseltamivir has a shelf life of five years, Hayden notes. He suggests that hospitals build a stockpile of five times their annual use of oseltamivir. The University of Virginia recently built a stockpile of 1,000 treatment courses, he says.
"It’s not just for a pandemic," Hayden explains. "It might be a year where there’s a bad vaccine match or a shortage, where you have an increased rate of illness in target populations."
• Establish good communication and collaboration.
"Communication is usually the weakest link," says David Henderson, MD, deputy director for clinical care at the Warren Grant Magnuson Clinical Center at the National Institutes of Health (NIH) in Bethesda, MD.
NIH has been collaborating with nearby institutions — National Naval Medical Center, Suburban Hospital Healthcare System, and the Uniformed Services University for the Health Sciences. A preparedness group initially began meeting weekly about two years ago.
Now they meet once or twice a month. The partnership was prompted by the commander of the National Naval Medical Center, who recognized the importance of the hospitals working together in a post-9/11 world.
"We basically just sat around the table and brainstormed what the various organizations bring to the table," Henderson recalls.
"For us, that was enlightening. It became clear very quickly that by working together we really had way more than we could possibly have by working independently," he adds.
NIH conducted emergency preparedness drills with its partners and learned, among other things, that the best way to communicate would be with radios.
NIH does not have an emergency department, but it could take patients from Suburban Hospital, leaving that hospital with greater capability to handle a surge of patients, Henderson says.
While severe acute respiratory syndrome (SARS) presented a model for the hospitals to cope with an airborne infectious disease, pandemic influenza poses unique challenges, he explains. "Pandemic flu will present a real stress on any one of the systems because of the way the disease is transmitted and because of the ease with which it gets transmitted in the community," Henderson adds.
The collaborative focuses on all types of emergency preparedness, but those plans directly address the potential for pandemic flu.
"Of the significant events that could happen — natural or man-made disaster events — this is one we know is coming," he says. "We just have to get ready for it."
References
1. Meltzer MI, Cox NJ, Fukuda K. The economic impact of pandemic influenza in the United States: Priorities for intervention. Emerg Infect Dis 1999; 5:659-671.
2. World Health Organization. Assessing the Pandemic Influenza Threat. Geneva; January 2005. Web site: www.who.int/csr/disease/influenza/en/H5N1-9reduit.pdf.
3. Hayden FG. Pandemic influenza: Is an antiviral response realistic? Pediatr Infect Dis J 2004; 23:S262-S269.
As avian influenza cases continue to emerge in Vietnam, the call for pandemic preparedness is gaining urgency. Between mid-December and mid-March, there have been 24 human infections of influenza A (H5N1) in Vietnam 13 of them fatal. Public health experts caution the virus could mutate and become transmissible among people the key to a pandemic.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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