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Avian flu threat intensifies need for preparedness (IDSA annual meeting)

It's only a matter of time before there's a pandemic of something.

By Amy Snow Landa, amednews correspondent. Nov. 21, 2005.

Reports from conferences important to physicians

Amid the growing international focus on vaccines and antiviral stockpiles to combat a predicted flu pandemic, a top global health official is underscoring the critical role to be played by doctors and nurses on the front lines of health care delivery.

Pharmaceutical interventions will be essential, but they aren't going to solve the problem on their own, according to Klaus Stohr, PhD, head of the World Health Organization's Global Influenza Programme.

20- to 30-day timetable
Disaster planning can help hospitals be ready
Specialists caution against overuse of curbside consultations
Treatment tips
Research findings
Links
See related content

"In the end, the effectiveness of the intervention all depends upon the physician, the hospital, the nurse and the technical equipment available at the local level," he said in a speech delivered at the Infectious Diseases Society of America's annual meeting Oct. 6-9 in San Francisco.

Although drugmakers are ramping up production capacity and nations are scrambling to stockpile the antiviral drug Tamiflu (oseltamivir), there simply will not be enough vaccine and drugs for everyone who needs them, Dr. Stohr warned. "We believe that if a pandemic comes, there will be a significant dependence on primary health care and hospital services for symptomatic treatment."

There also will be a heavy reliance on nonpharmaceutical interventions, such as quarantines, voluntary home stays and protective face masks to prevent the spread of infection, he said. "These barriers will be the ones to slow down the spread and help reduce morbidity and mortality."

Dr. Stohr's remarks at the IDSA meeting coincided with published reports that the deadly Spanish flu pandemic of 1918-19 first developed in birds and was similar to today's H5N1 avian flu virus, raising fears among national and international policy-makers that H5N1, like the earlier strain, could turn into a global human pandemic. Discoveries that the avian flu virus now has spread beyond Asia and as far as Turkey, Romania and Macedonia also have increased anxiety levels.

These and other developments suggest that H5N1 is accelerating its potential to cause an influenza pandemic, Dr. Stohr said. The virus is not just expanding its geographic reach, "it's increasing its pathogenicity."

By late October, global health officials feared that the deadly virus would jump next to East Africa, where countries are almost completely unprepared to control outbreaks. The virus also appeared to be flaring up again in Asia, where Thailand reported in October its first human cases of H5N1 in more than a year. So far, human cases of H5N1 infections remain limited to four countries in Southeast Asia, where the virus has caused at least 62 deaths. But experts warn that if the virus mutates into a form that is easily transmissible between humans, it is likely to spread rapidly with devastating consequences.

The need for speed

A significant aspect of avian flu is that its rate of transmission appears to be only two days, said Barry Bloom, PhD, dean of the Harvard University School of Public Health, who also spoke at the IDSA meeting. By contrast, the timeline for SARS was six to eight days.

"When one thinks of bird flu, with a serial interval of two days, I would like to be pre-armed with immunization, if I have a choice, rather than worry about recovering from an infection," Dr. Bloom said. Currently, there is no licensed vaccine that is considered effective in protecting humans from the H5N1 strain.

But experimental vaccines are undergoing human clinical trials, said Robert B. Belshe, MD, director of the Center for Vaccine Development at Saint Louis University School of Medicine. They include both active vaccines and live, attenuated vaccines.

One challenge, though, is predicting exactly which strain is going to emerge as a human threat. "Selecting a strain today may be a problem," Dr. Belshe warned.

According to Dr. Stohr, an effective vaccine is certainly not going to be available in the first three months of a pandemic outbreak, which is the length of time in which the virus is likely to spread worldwide. Even during subsequent months, the world's vaccine supply will be inadequate because of limited production capacity.

Without a vaccine, it is hoped that antiviral drugs could be used effectively to treat symptoms in patients who become infected with H5N1 and as prophylaxis in areas of pandemic flu outbreak. WHO has developed a "rapid response stockpile" of these treatments that it plans to deploy quickly to such areas in an effort to contain the virus and prevent it from spreading.

The intervention would need to be quick to be effective, Dr. Stohr said. "The window of opportunity to extinguish or eliminate the pandemic virus is very narrow -- between 20 and 30 days from when the virus emerges until the time it's too late."

In the scenario he outlined, at least four to five days will elapse between the onset of symptoms in patients infected by the pandemic flu strain and when they are admitted to the hospital. It would take several more days -- possibly a week or more -- to determine a diagnosis, conduct a field investigation and characterize the virus.

WHO then would have about 10 to 14 days to intervene by broadly distributing antiviral prophylaxis to the affected population. The strategy has never been used and may not be successful, he said. "But we would not be forgiven if we did not try it."

In the meantime, the United States and other nations are racing to increase their own stockpiles of antiviral drugs.

President Bush, for instance, announced Nov. 1 that he would ask Congress for $7.1 billion to begin implementing a preparedness plan. Specifically, the plan would provide $2.8 billion for research to speed vaccine development, $1.2 billion to buy vaccine effective against the strain of avian flu currently circulating and $1 billion for the purchase of antiviral medications.

ADDITIONAL INFORMATION:

20- to 30-day timetable

The timetable for activity of pandemic virus:

	Lasts	Takes place
Onset to admission	4-5 days	Day 1 to Day 5
Sampling to diagnosis	2-4 days	Day 6 to Day 9
Virus characterizaton	5-7 days	Day 10 to Day 16
Field investigation	3-4 days	Day 13 to Day 16
Intervention	10-14 days	Day 17 to Day 30

Sources WHO Global Influenza Program

Disaster planning can help hospitals be ready

Hospital leaders should be taking certain measures now to prepare for the challenges their institutions are likely to face in the event of an influenza pandemic, according to William Schaffner, MD, hospital epidemiologist at Vanderbilt University Medical Center in Nashville, Tenn.

Hospitals could encounter problems with security if patient demand for vaccines and antiviral drugs becomes greater than the supply, he said. "Biological supplies and antiviral drugs [will be] the Hope Diamond -- they have to be protected and secured."

Dr. Schaffner was one of several speakers who addressed the front-burner issue of pandemic flu preparedness at the Infectious Diseases Society of America's annual meeting this year.

For hospitals, the "single most important thing" is to have a disaster-planning coordinator who can make preparedness -- whether for flu or for flood -- a sustained priority and bring together diverse interests to engage in the planning process.

Live drills are also essential, he said. "Because as you drill, the plan comes off the page and you discover very quickly what works and what does not."

It can be difficult to get physicians to participate in drills that cut into clinical time, he noted, but they should be involved. It's also important to have a "flu team" in place, as Vanderbilt discovered during a severe influenza outbreak last year, he added. Hospitals need to evaluate their surge capacity and antiviral stockpiles.

And finally, it's important to encourage all health care professionals to be vaccinated against seasonal influenza, he said. "While we're planning for a pandemic, we know that influenza will visit us each year."

Specialists caution against overuse of curbside consultations

In his 28-year career as an infectious disease specialist, Thomas G. Slama, MD, has developed elaborate strategies to avoid getting "curbsided" by other physicians seeking advice on a patient's diagnosis or treatment.

"I have secret ways into the hospital," he told colleagues in a speech at the Infectious Diseases Society of America's annual meeting in San Francisco.

But in the end, his strategies don't work. "I can't hide," Dr. Slama said. He estimates that curbside consultations -- informal and unpaid -- make up about half the consultations he provides each year.

Although he jokes about his efforts to avoid them, Dr. Slama is serious when he says such requests are often inappropriate and should be discouraged. Infectious disease specialists, cardiologists and gastroenterologists tend to get curbsided most often, according to a 1998 study published in the Journal of the American Medical Association.

The most serious problem with these exchanges is they can be dangerous for patients, he said. Information provided by the treating physician is sometimes incomplete, making it difficult for the specialist to give good advice. It's like being asked, "Can you name this tune in three notes?"

In a formal consultation, the specialists have a chance to learn all of the clinical information and to examine the patient directly before offering suggestions, Dr. Slama added.

Sometimes a curbside consultation is appropriate, usually when it involves a straightforward question that can be answered quickly, Dr. Slama said. At those times, an ID specialist should feel free to respond. "But if a case is complex, don't talk," he advised colleagues.

Infectious disease specialists in the audience also expressed concern that curbside consultations result in a significant amount of lost income. Researchers from the University of Vermont College of Medicine reported that these interactions accounted for 22% of the clinical work value performed by their ID unit during a recent six-month period. They estimated that had the curbside consultations been performed as formal consultations, they would have provided nearly $50,000 in additional revenue.

Treatment tips

Here are some treatment tips from the meeting:

Patient satisfaction not tied to antibiotic scripts. Receipt of an antibiotic does not significantly affect patient satisfaction after an initial visit for acute respiratory tract infection, according to researchers from the Centers for Disease Control and Prevention, Wisconsin Division of Public Health and Marshfield Clinic Research Foundation.

Patient satisfaction among adults with ARTI and parents of children with ARTI was significantly associated with factors such as the amount of time the clinician spent with the patient and the clinician's personal manner, not the receipt of antibiotics, researchers found by linking outpatient survey data with pharmacy claims data for antibiotics.

Vibrio wound infections more common than thought. Wound infections caused by Vibrio bacteria are more common than previously thought and have led to the deaths of at least five people in the aftermath of Hurricane Katrina, according to researchers from the Centers for Disease Control and Prevention.

Of the approximately 8,000 Vibrio infections in the United States every year, they found that nearly one in four could be caused by a cut or wound that is exposed to warm brackish or sea water. The others are caused by eating raw oysters or undercooked seafood.

"It is important for clinicians to consider Vibrio when looking at wound infections and to take a careful travel history from the patient," said principal investigator Amy Dechet, MD.

Research findings: Pertussis, pneumonia treatment

During a community-wide pertussis outbreak in Tennessee, azithromycin was better tolerated and associated with substantially higher completion rates than erythromycin, said researchers from the Tennessee Dept. of Health, Mid-Cumberland Regional Health Office and Vanderbilt University. Their findings were presented this fall at the Infectious Diseases Society of America annual meeting in San Francisco.

Among patients who were prescribed 56 doses of erythromycin over 14 days, 57% completed treatment. Of those given 14 doses of azithromycin for six days, 94% finished treatment.

Currently, erythromycin is the recommended antimicrobial for pertussis. But researchers suggested re-evaluating the national recommendations for pertussis prophylaxis to include azithromycin, which is more expensive but requires fewer doses.

Another study presented at the conference found that hospitalization rates for pneumonia among adults age 65 and older are increasing, even though all-cause hospitalization rates in that age group are not.

Researchers at the Centers for Disease Control and Prevention examined trends in pneumonia hospitalizations for this demographic from 1988 through 1990 and from 2000 through 2002. The rates for people with pneumonia listed as the first cause increased by 20% during that period.

Co-diagnoses with underlying chronic diseases also are increasing. This age group's three most common co-diagnoses were chronic cardiac disease, chronic pulmonary disease and diabetes mellitus. The number of patients with pneumonia and one of these conditions increased 17%.

A separate study by researchers from the CDC and several emerging infections programs around the country found that the introduction of the 7-valent pneumococcal conjugate vaccine in 2000 has dramatically reduced invasive pneumococcal disease among children younger than age five and adults 65 and older. But disease caused by serotypes not included in the vaccine is increasing.