Published in the January 2009 issue of Today’s Hospitalist
Just how much protection do flu immunizations give elderly patients who are sick and frail enough to require hospitalization? As hospitalists brace themselves for this year’s flu season, many are talking about a journal article that addressed that exact question.
The study, which was published in the Aug. 2, 2008, issue of The Lancet, concluded that the effectiveness of vaccinating elderly patients for the flu during influenza season was “strikingly lower than previous estimates.” Vaccination, researchers concluded, was not associated with a significant reduction in elderly patients’ risk of getting community-acquired pneumonia during flu season.
While this recent study is only one in a growing list of research that questions the effectiveness of the flu vaccine, it’s the first to address the patient population that many adult hospitalists tend to treat. The study is now cropping up in discussions about the role vaccines should play in elderly patients.
For now, however, the message from many experts “including the study’s lead author “is one of caution. While everyone seems to agree that the study raises some important questions about flu vaccination for the elderly, experts also say that physicians shouldn’t change how they practice, at least for now.
Targeting high-risk patients
For the study, researchers targeted a group of patients who were most at risk for developing flu-related pneumonia (over age 65, with at least half over 75) and also most likely to benefit from immunization because they were not already immunocompromised with serious cancer or renal failure.
“We wanted to pick a group in whom the vaccine actually had a good shot,” explains Lisa A. Jackson, MD, the study’s senior author and a researcher at the Group Health Center for Health Studies in Seattle.
She and her colleagues selected three flu seasons “2000, 2001 and 2002 “in which there was a good match between the vaccine and the circulating strains. When they reviewed the medical records of the more than 3,500 patients at Group Health, researchers found that the patients treated for community-acquired pneumonia had similar rates of flu vaccination as did those who remained healthy.
By also comparing the groups during a control time period “after flu vaccine became available but before flu season started “researchers were able to conclude that a more important factor in whether this older population contracted pneumonia was patients’ underlying health status, not their flu-shot status.
“This is not to say that the vaccine is doing nothing,” says Dr. Jackson. “But it is not having an impact we can detect. It is certainly not doing as well as previous studies had suggested.”
A look at the evidence
Dr. Jackson’s observational study is particularly interesting given the fact that the one randomized controlled trial to look at the efficacy of influenza vaccination on the elderly was conducted nearly 15 years ago.
That study, which was published in the Dec. 7, 1994, Journal of the American Medical Association, looked only at younger, healthier “elderly” who were age 60 and older. Statistics show that about half of patients who are hospitalized with pneumonia, which is the most common serious complication of flu, are 80 and older.
The 1994 study found that the flu shot reduced flu incidence by about 50% in the younger, healthier group. But Dr. Jackson says that “we don’t have any idea of how well the flu vaccine works in people who are 80 and older and those who have serious chronic illness.” From what we know about immunization and the flu, she adds, “we have to think it is not going to work as well.”
Another study, this one published in the Feb.14, 2005, Archives of Internal Medicine, concluded that observational studies that report that influenza vaccination reduces winter mortality risk among the elderly “substantially overestimate vaccination benefit.” While rates of annual flu shots have significantly increased among the elderly, those researchers found, influenza-related mortality among those patients has also increased.
And a Canadian study published in the Sept. 1, 2008, American Journal of Respiratory and Critical Care Medicine also concluded that the mortality benefits of influenza vaccination have been “overestimated” because of a “healthy-user benefit.” That means that healthier patients are the ones who both tend to get vaccinated and tend not to get as sick.
While Dr. Jackson’s study raises interesting questions about the impact of the flu vaccine on frail, elderly patients, she still recommends that patients ” including her own mother “receive an annual flu shot.
“The bottom line is that there aren’t really any alternatives,” Dr. Jackson explains. “The flu vaccine probably isn’t as good as we have thought, but it is not harmful, and it probably has some benefit in some people. The issue is the degree of match between the people who benefit from the vaccine and those who experience outcomes like hospitalization.”
While she does not think the evidence is as strong as it could be to support inpatient vaccination initiatives, “the train has left the station, so should we be putting a halt to things?” she asks.
“We know that flu can cause serious illness and death and that the vaccine does work in some people. The real question, therefore, is whether the vaccine is working in people who have serious illness and are at the highest risk of death during flu season.”
That pragmatic approach is echoed by hospitalists who have pioneered influenza efforts at their hospitals. Alexander Carbo, MD, a hospitalist who helped engineer the inpatient influenza immunization initiative at Boston’s Beth Israel Deaconess Medical Center, says that while he doesn’t view the study’s results as “a practice changer,” that could change if studies with similar conclusions follow.
“We might be having a different conversation a few years from now,” Dr. Carbo says. “This study says to me that the vaccine may not be as effective for elderly patients as we previously had thought, but that we also need more study.”
He adds that while Dr. Jackson’s study “did knock some holes in the theory” that all elderly patients should be immunized, “we still think it is a great idea to immunize these people who are at risk.” That’s not just a public health issue, he adds, because flu shot rates for patients with pneumonia are being publicly reported by the Centers for Medicare and Medicaid Services. Some payers, as well as the Joint Commission and other quality improvement organizations, are also tracking inpatient flu shot status as a quality indicator.
Other outcomes of concern
Jeffrey L. Greenwald, MD, the director of the hospitalist program at Boston Medical Center who spearheaded the multidisciplinary inpatient influenza vaccination initiative there, agrees that the recent study should give physicians “some pause.”
But he is quick to add that pneumonia is not the only adverse outcome of influenza that physicians are trying to prevent through immunization.
As a practicing hospitalist, he would like to see research into a broader range of outcomes that could be analyzed to determine the efficacy of flu vaccine. These could include the number of days with febrile illness, the number of days of hospitalization or the number of days of feeling debilitated.
“Like so many times in medicine, when you get an unexpected result or a result contradicting prior literature, it can’t be ignored,” he says. “But it needs to be put in the context of the rest of the literature.”
Dr. Greenwald remains swayed by the fact that government and professional society recommendations continue to favor vaccination as they consider reasons beyond pneumonia as outcomes of concern. He also cites literature that suggests there is a partial benefit for patients “even if you vaccinate with the wrong strain.”
Toward a truly protective vaccine
Dr. Carbo says he likewise will continue to follow recommendations from the CDC and other leading health care organizations. The CDC reports that 226,000 people are hospitalized every year because of influenza and that 36,000 die, most of them elderly.
As he continues to tweak Beth Israel Deaconess’ inpatient immunization initiative, Dr. Carbo points out that hospitalized patients are “the ones who you really don’t want to get the flu. The CDC says “and I agree “that if these patients are in your hospital, even though that might not be the best time to immunize them, it’s better than nothing.”
Dr. Jackson says that she would like to see results of studies like hers spur new research into developing a truly protective flu vaccine. The current vaccine was developed in the 1940s for healthy adults and was never specifically tested in the elderly, an omission that drug regulators would never permit today. Dosing is the same for everyone age 3 and older, despite the fact that research into this and other vaccines clearly demonstrates that older adults do not respond as well to vaccines as younger adults.
“The major adverse consequence of accepting these false results up to now,” says Dr. Jackson, “has been to stymie research into flu vaccine development for the elderly.”
Deborah Gesensway is a freelance health care writer based in Sierra Madre, Calif.
Vaccinating health care workers: Is it good medicine?
THE PUSH IS ON from a number of organizations to dramatically increase the number of health care workers who get flu shots.
This year, the Association for Professionals in Infection Control and Epidemiology not only recommends flu shots for all health care workers, but it’s urging hospitals and other facilities to “obtain informed statements acknowledging the risk to patients from employees who decline the vaccine for reasons other than medical.” And more than 1,300 hospitals have signed on to a flu vaccination challenge issued by the Joint Commission to raise workers’ immunization rate above 42%.
Immunizing health care workers seems to make sense given the fact that people with influenza are infectious for a day or so before they are symptomatic. However, there’s little in the way of data for proof. A Cochrane Collaboration review published on July 19, 2006, for example, concluded that “an incremental benefit of vaccinating healthcare workers for the benefit of the elderly cannot be proven without better studies.”
Given the dearth of data, Lisa A. Jackson, MD, an internist and vaccine researcher at Seattle’s Group Health Center for Health Studies, says she remains a “skeptic” about how large of a benefit may be gained from the current push to immunize health care workers.
“You have to look at the modes of transmission to estimate the risk of patients being infected by health care workers, and this risk likely varies substantially depending on the clinical setting,” says Dr. Jackson, who published a recent study that called into question the effectiveness of flu vaccine in lowering pneumonia risk in elderly patients. While vaccinating health care workers will reduce their risk of getting the flu and could potentially prevent illness in patients, she says, “it would be optimal to have better data on the latter.”
One hospital’s success with a flu-shot initiative
TALK TO THE HOSPITALISTS at Boston’s Beth Israel Deaconess Medical Center, and you’ll learn that nearly every patient admitted during flu season is offered a flu shot. You’ll also hear that the hospital’s rate of flu immunization represents a nearly total reversal from three years ago, when few patients in the hospital were immunized against the flu.
Alexander Carbo, MD, a hospitalist who worked with a nurse, a pharmacist and a computer programmer to launch the hospital’s flu vaccine initiative, says that success came in several phases.
During the program’s first year, for example, the team focused only on educating staff about the need to vaccinate patients.
The team’s next move was to implement passive prompts in the electronic medical record that simply reminded physicians that flu vaccine was available. When that strategy didn’t boost immunization rates, the team launched what Dr. Carbo calls “forced prompts.”
That means that doctors who haven’t addressed a patient’s flu shot status by the time of discharge are forced to do so by having to answer a series of questions asking why the patient hasn’t been immunized. Those moves pushed flu-shot screening rates among inpatients from an abysmal 3% to 80%.
The initiative’s latest tweak is to make sure flu shots are given sooner in the course of hospitalization, not put off until discharge. Now, Dr. Carbo says, admitting physicians automatically order a nurse-run flu shot protocol that can take place anytime while patients are hospitalized. The initiative is also working on improving the discharge summary to make sure outpatient providers know that patients got a flu shot during hospitalization. The hospital’s overall vaccination screening rate last year was 86%; the goal this year is 90%.
Despite the team’s success, Dr. Carbo says its work is not done. One ongoing goal of the program is to counter myths about flu immunization. The most persistent one is that a flu shot causes flu. Another pernicious myth is that vaccination is an outpatient issue.
“There are good data that Americans are not getting immunized in the outpatient world,” says Dr. Carbo. While that’s bad news from a public health perspective, it creates a great opportunity for hospital teams to step in and help fill the void.