Many hospitals lack policies on flu detection
Basic precautions can halt nosocomial spread
Many hospitals are unprepared to detect influenza among patients and staff, despite the availability of rapid diagnostic tests, according to two national surveys.
A questionnaire sent by the Infectious Diseases Society of America (IDSA) in Alexandria, VA, to members of the Emerging Infections Network represents one of the first efforts to determine how prepared hospitals are to prevent nosocomial influenza outbreaks.
Only 10% of 474 infectious disease clinicians responding said their hospital had a policy in place to screen patients for flu-like symptoms in the winter months, and 7% had a policy on the screening of health care workers. Less than half (49%) had access to rapid diagnostic tests to allow a swift detection of influenza.
A survey of 34 hospitals that belong to the National Surveillance System for Health Care Workers (NaSH) — part of the Hospital Infections Program at the Centers for Disease Control and Prevention — produced similar results, with about half having access to rapid diagnostic tests for influenza and only 27% conducting routine exposure investigations when flu is suspected.
"Hospitals don’t think about influenza as a very severe disease," says Matthew J. Kuehnert, MD, a medical epidemiologist with the CDC’s hospital infections program. "There’s not a lot of effort to try to detect it."
Larry Strausbaugh, MD, project director of the IDSA Emerging Infections Network, says he hopes the findings will spark a national discussion about prevention of nosocomial influenza outbreaks. The CDC recently released a draft report urging hospitals and other health care facilities to develop a plan for responding to pandemic influenza. (See Hospital Employee Health, July 2000, p. 73.) Strausbaugh is a hospital epidemiologist and staff physician at Portland (OR) Veterans Affairs Medical Center and professor of medicine at the Oregon Health Sciences University School of Medicine, also in Portland.
"You could argue if you’re not prepared to deal with the annual expected influenza prevention issues, how on earth are you going to be prepared for the pandemic?" he says.
The lack of hospital policies on influenza diagnosis and outbreak prevention stems in part from an absence of guidance.
Each year, the Advisory Committee on Immu-nization Practice, a federal panel of experts, issues detailed recommendations on immunization. Yet guidelines have not been developed on other issues, such as when to use chemoprophylaxis, or antiviral drugs, and when to administer rapid diagnostic tests.
Should every unvaccinated health care worker with respiratory symptoms be screened for influ-enza? Should all admitted patients be screened during the peak of influenza season? Are those policies cost-effective? When should employees use droplet precautions (i.e. masks) to prevent nosocomial spread of possible influenza?
The CDC is considering recommendations on these and other issues, but the supporting research is limited, says Carolyn Buxton Bridges, MD, a medical epidemiologist in the influenza branch of the CDC. "The best ways to implement surveillance are going to vary from setting to setting," she says. "Those [screening and surveillance issues] are questions we need to look at, and we are going to attempt to do that to provide more specific guidance."
CDC’s Hospital Infections Program recently set up a Web site with questions and answers about preventing nosocomial influenza outbreaks. (www.cdc.gov/ncidod/hip/infect/flu_acute.htm). Printed educational materials also are being developed, says Kuehnert.
"We thought it would be important to get something out there, a suggested approach. This came from a perceived need that the hospitals had to have some direction," he adds.
The NaSH survey found that some employee health and infection control professionals didn’t recognize influenza as a significant nosocomial risk. They also cited difficulties in conducting outbreak investigations. "They just didn’t have the time or resources to do the investigations," says Kuehnert.
Hospitals need plan for outbreaks
CDC officials want hospitals to focus primarily on vaccination of health care workers to prevent spread of influenza. (See related article, p. 114.) But they also want hospitals to consider other issues of surveillance and outbreak control.
Hospitals may need to individualize these policies based on a variety of factors, including the prevalence of influenza in the community during a particular flu season, Bridges notes.
Influenza experts need to address what the influenza prevention goals would be for different kinds of facilities, says Strausbaugh. "I don’t think it’s a situation where one size fits all," he says.
For example, in long-term care facilities, administering chemoprophylactic drugs to residents can stop an outbreak of influenza. But a hospital has a much more mobile population, including volunteers and visitors who may spread community-acquired virus.
These issues of screening, vaccination, and prophylaxis came into sharp focus at a New York hospital that suffered an influenza outbreak in the 1998-99 flu season. CDC flu experts visited the hospital and identified 10 cases of nosocomial influenza and 38 cases of flu-like illness that could not be confirmed by culture. Only 11.5% of health care workers had been vaccinated before the outbreak, and unvaccinated workers may have initiated the spread of the illness, says Bridges. The hospital suffered high absenteeism rates due to influenza among staff.
"Even after the outbreak, it was hard to get high rates of vaccination among the health care workers," say Bridges, noting that the rate rose to about 40%. "There was a lot of misunderstanding regarding the benefits and risks of the vaccine."
When CDC officials surveyed staff to find out why they declined the vaccine, they uncovered a significant amount of misinformation. Some employees thought they would get influenza from the vaccine; others thought it was not effective. (The vaccine is 70% to 90% effective.) Pregnant and breast-feeding women didn’t want it, even though the vaccine is not contraindicated for that population.
The hospital offered the vaccine to health care workers during the outbreak, and placed employees on amantadine, an antiviral, for the two weeks it takes to develop immunity after the vaccine. Some 40% of employees on amantadine stopped taking it due to side effects.
Amantadine can cause insomnia, dizziness, and nervousness. Rimantadine, another antiviral, is more expensive but is less likely to cause those side effects, says Bridges.
Meanwhile, with cohorting of patients, the use of droplet precautions, and other standard infection control measures, the hospital was able to halt the nosocomial outbreak. The following year, an education campaign helped the hospital improve vaccination rates among health care workers.
"We can’t take for granted that health care workers, because they’re in the health care field, know about influenza vaccine," says Bridges. "We have to do a better job of letting them know what the true impact of influenza is, that it can be a very serious illness."
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