"The flu shot is even better than we thought," confirms Dr. Kristin Nichol, lead author of a study appearing in the April 3 issue of The New England Journal of Medicine.
According to the article, influenza-related deaths in the United States have increased over the past 20 years, with 90 percent occurring among the elderly. At the same time, the vaccination rate is static, with only 63 percent of seniors getting immunized in 2001.
"Immunization rates for people 65 and older have been fairly flat in this country for the past five years or so," says Nichol, who is chief of medicine at the Veterans Affairs Medical Center in Minneapolis. "They're still under 70 percent, with a national goal of 90 percent by 2010. It's a pretty big gap, and it doesn't look like we're making a lot of progress."
"That's something we clearly have to do much better," adds Dr. Edward Chapnick, director of infectious diseases at Maimonides Medical Center in New York City. "What makes it even more important is the rising problem with antibiotic resistance. The flu is not bacterial but it predisposes bacterial infections, so there's a whole host of reasons that it's incredibly important for everyone to get the flu shot. Those reasons are becoming more important all the time."
Influenza is particularly dangerous for elderly people because it increases the risk of developing pneumonia and of exacerbating existing heart and other conditions. It's well-known that during influenza outbreaks, hospitalizations for stroke and cardiovascular problems surge.
Smaller studies have suggested that influenza vaccinations reduce the risk of heart attack and stroke, and that they also decrease the number of hospitalizations.
The current study both confirms these previous studies and brings new information to the table.
"We looked at some outcomes that have previously been studied -- pneumonia and influenza, hospitalization and death," Nichol says. "The heart and stroke hospitalizations are really the new piece here."
Nichol and her colleagues analyzed two large groups of people during two different flu seasons (1998-1999 and 1999-2000) to see if getting vaccinated resulted in reduced rates of hospitalization and death for cardiac and cerebrovascular disease, including stroke.
All of the participants were at least 65 years of age, belonged to one of three managed-care organizations covering eight states, and all lived in the community -- in other words, they were not confined to nursing homes or other institutional settings and are therefore more representative.
The first group was composed of 140,055 people who were studied during the 1998-1999 flu season, 55.5 percent of whom were immunized. The second group consisted of 146,328 people during the 1999-2000 flu season, 59.7 percent of whom were immunized.
Vaccination was associated with a 19 percent reduction in the risk of hospitalization for cardiac disease in both seasons. The risk for cerebrovascular disease was reduced 16 percent in the 1998-1999 season and 23 percent during the 1999-2000 season. There was a 32 percent drop in risk for pneumonia or influenza during the 1998-1999 season and a 29 percent decline in the 1999-2000 season. The overall risk of death was reduced by 48 percent during the 1998 to 1999 season and 50 percent during the second season.
It's not clear why these benefits are being conferred. The authors postulate that inflammation resulting from having the flu may exacerbate vascular disease.
Regardless of the underlying reasons, the message is clear. "I hope this study helps to encourage people to take influenza seriously and to take seriously the importance of delivering the vaccine," Nichol says.
Health-care providers need to help get that message across, Nichol adds. "We knew that if a provider recommends a flu shot to a patient that the patient is very likely to accept it, if they give a clear message that this is good for you, this is safe," she says. Protocols also need to be in place that let nurses administer the vaccine without needing to get the physician involved. "That's very effective," Nichol says.
Chapnick suggests people also get the pneumonia vaccine.
"We can prevent hospitalizations, save lives," Nichol concludes. "When I think of it from a public health perspective as well as from a provider/patient perspective, I feel like saying, 'Folks sit up. Open your eyes. Look at these benefits.' Is there anything else we do in medicine for adults that provides this kind of benefit in such a short period of time? I'm not aware of anything."
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