Flu Shots Cut Hospitalization in Elderly

April 2, 2003 -- Flu shots are important -- especially for the elderly. When elderly people get vaccinated, they are less likely to be hospitalized for stroke, heart attack, and flu during the flu season. They are also less likely to die during this season.

A study of this issue appears in this week's New England Journal of Medicine.

During flu season, the numbers of people hospitalized goes up --- due to stroke, heart attack, and acute respiratory infections, writes lead researcher Kristin L. Nichol, MD, a researcher with the Veterans Affairs Medical Center in Minneapolis.

However, her study shows that among the elderly, flu shots resulted in "substantial reductions" in hospitalizations for both stroke and heart attack, writes Nichol. This may be due to the extra stress that serious infection puts on the body, especially if the elderly person already has heart problems or blood vessel blockages, she explains.

In their study, Nichol and colleagues analyzed the medical records of thousands of people over age 65 -- more than 140,000 people during the 1998 to 1999 flu season, and more than 146,000 during the 1999 to 2000 flu season. They looked to find an association between hospitalization in the elderly during this period and whether they received flu vaccines.

During 1998 to1999 winter, those people who got flu shots were:

• 19% less likely to be hospitalized for heart attacks
• 16% less likely to be hospitalized for stroke
• 32% less likely to be hospitalized for pneumonia or influenza
• 48% less likely to die

Numbers were similar for the 1999 to 2000 flu season. Those who got flu shots were:

• 19% less likely to be hospitalized for heart attacks
• 23% less likely to be hospitalized for stroke
• 29% less likely to be hospitalized for pneumonia or flu
• 50% less likely to die

Studies conducted in the U.S., Canada, and the U.K. have also shown a reduced risk of death -- by 30% to 50% -- in elderly people who have had flu vaccines. Studies have also shown fewer heart attacks and stroke among elderly people who receive flu shots, although not all of these smaller studies have found that flu shots protect against heart attacks.

SOURCE: The New England Journal of Medicine, April 3, 2003.