February 16, 2006
Area pandemic planning well under way
In case a pandemic flu arises, contingency planning is under way at a global, federal, regional, state, county, city, business, hospital, and clinic level. The U.S. Department of Health and Human Services suggests that all adults plan ahead for a major influenza outbreak.
The UW, and its affiliated hospitals and clinics, are coordinating with area public health departments on institutional preparedness plans that take into consideration patients, health-care providers, researchers, faculty, staff, students, and others who are part of the daily life of the UW. In addition, the UW hospitals and clinics are collaborating locally and regionally on their community response plans.
Influenza pandemics occur when a new flu virus appears that no one has been exposed to previously and that has the ability to pass from person to person. Because almost everyone would lack immunity to the new strain, the flu would spread quickly and could cause severe illness. The death toll would likely be high. Some people, on the other hand, will have only mild to moderate symptoms. Large-scale outbreaks may move in waves, and each could last for a few months. Up to one-third of the workforce could be sick at the same time during a pandemic. Disruptions could occur in transportation and other public services, schools and stores may close, and hospitals and clinics could be understaffed and overwhelmed.
The World Health Organization has been at a phase 3 pandemic alert for a couple of years. This level indicates that a new influenza A subtype is causing human disease, but is not yet spreading widely among people. In this instance, the subtype is N1H5, commonly known as bird flu.
Dr. Corey Casper, UW assistant professor of medicine in the Division of Allergy and Infectious Diseases, explained that, within each type of flu (A, B, or C), viruses are subtyped by two proteins on the virus surface. Haemagglutinin enables a virus to attach to a host cell, and neuraminidase turns the host cell into a flu virus factory. The human immune response to the flu is largely directed against these two proteins. Casper said. At present, the NIH5 subtype is spread bird-to-human from close contact with live, infected poultry. The strain probably originated in wild, migratory waterfowl, which carried it to poultry farms and live bird markets.
Flu viruses can change into new forms. They drift, that is, undergo subtle changes when genetic mistakes made during replication are not corrected, or they shift, which means they swap genetic material with other flu viruses. If a person is simultaneously infected with an ordinary, seasonal human flu virus and an avian flu virus, conditions become ripe for the avian flu virus to gain the genetic wherewithal to be contagious from person-to-person.
The Centers for Disease Control and Prevention, along with the World Health Organization, continuously conduct surveillance for the initial appearance of any potentially epidemic flu. Labs around the world chart the geographic distribution of viruses, identify new strains, and monitor viruses for drug resistance. In the United States, 1,000 health-care providers report weekly on the number of patients they have seen with flu-like symptoms, and 122 cities report the number of deaths in which pneumonia or influenza were contributing factors. Each week the states estimate their level of influenza: no activity, sporadic, local, regional, or widespread.
Dr. Ira Longini is a professor of biostatistics who moved to the UW and the Fred Hutchinson Cancer Research Center in January from the Rollins School of Public Health at Emory University in Atlanta. He is among the experts working on national flu containment strategies. A specialist in mathematical models of infectious diseases, he and his colleagues have created simulations to predict the effectiveness of public health interventions in containing an emerging influenza strain. For example, they have run computer models of quarantines, pre-vaccinations, and antiviral medications as a preventive or treatment measure in a targeted population.
“Using tabletop drills, several agencies are looking at different scenarios of a flu pandemic,” said Dr. Anne Kimball, professor of epidemiology and health services. “They can shift the variables, show what might happen, and test how we would cope.” Kimball directs the Emerging Infectious Disease Network of the Asia-Pacific Economic Cooperation (APEC).
She added that the antiviral Tamiflu has been useful against recent cases of bird flu in humans. Several countries are trying to stockpile the drug and set priorities for its use. A number of Asian countries, such as Indonesia, are working with Roche, the Swiss pharmaceutical company, to create places outside of Europe where Tamiflu can be manufactured. Several experts predict that Tamiflu will be in short supply and that there will not be enough of it to control a pandemic. While there is no vaccine for H1N5 flu, preliminary tests are being conducted on potential vaccines. Longini is among those working on ways a vaccine, if a suitable one is available in the early stages of a pandemic, might be most wisely distributed.
“Schools provide a ready access to a population at risk,” Longini said, “and vaccinating children will help protect them and their communities.” Even if a percentage of parents object to vaccination, a 70 percent compliance rate, he said, could help reduce an outbreak. Of concern is that a vaccine may not be developed in time and distributed in sufficient quantities. Injected vaccines take at least two weeks to provide protection; inhaled vaccines work faster. Although new technology, such as tissue culture, is being developed, vaccine must now be grown on chicken eggs. This technique is slow, laborious, and doesn’t work well with this particular strain.
Also lacking will be hospital beds and ventilators (medical machines that help patients breathe). Most hospitals were designed with patient privacy in mind and to operate at peak efficiency without wasted space. Kimball mentioned that some hospitals in Asia can temporarily expand to accommodate an overflow. Many cities are looking for spaces where large numbers of people might be treated. Otherwise healthy people with mild symptoms might be better off riding out the flu at home.
Darrell Owens, clinical assistant professor of nursing and director of palliative care at Harborview Medical Center, wants to be sure comfort is given to those unlikely to survive pandemic flu. When large numbers of people become terminally ill so quickly, new ways of caring for those near death will be needed, he said. For example, he said, a patient may be solaced simply by holding a cell phone up to his ear so that his son can say goodbye from across the country.
Numerous suggestions for managing a flu pandemic are being discussed. However, several local public health officials say that many of these will be difficult to implement without additional staffing and funding.
If the world avoids a flu pandemic, several UW experts said that the preparation would be worth it. Strong international collaborations on this matter have led to improved communications and relationships between nations. Locally, connections between agencies have been established. These connections would serve the area well in any type of disaster response.
“Nations are aware that pandemic flu is a global problem, and international cooperation has been quite good,” Longini said. “Public health is traditionally one of the few arenas where the world’s nations seem to work together effectively.”
