Flu deaths rising sharply as population ages, study shows
By ANDRé PICARD
PUBLIC HEALTH REPORTER
Thursday, January 9, 2003 – Globe and Mail Page A5
The number of people dying annually from the flu has risen dramatically during the past two decades, a striking example of how the aging of the population is shifting public-health challenges.
New data from the U.S. Centers for Disease Control and Prevention published yesterday show that about 65,000 people died of influenza and related respiratory illnesses in 1999. That is up sharply from 23,000 deaths in 1990 and 16,000 in 1976.
William Thompson, head of the influenza branch of the CDC said the increase can be explained, in part, by the fact that the number of people aged 85 years or older has more than doubled since 1976. Frail seniors are most vulnerable to influenza because their immune systems are weaker and the flu vaccine is less effective.
The new study, published in the Journal of the American Medical Association, found that people over the age of 85 are 32 times more likely to die of influenza than those between the ages of 65 and 69.
The research also shows that respiratory syncytial virus accounts for the deaths of more seniors than previously believed.
The CDC scientists found that almost 18,000 people die of RSV in the United States each year, even though it is viewed as a viral illness that tends to affect children.
In fact, more than 90 per cent of influenza deaths and 78 per cent of RSV deaths were recorded in people older than 65.
Dr. Thompson said the number of deaths attributable to influenza and RSV are difficult to estimate because these infections tend not to be confirmed with virological tests and they are rarely listed as a cause of death. (That is because the deaths are usually due, ultimately, to secondary complications such as pneumonia or superbacterial infections.)
While the new figures are from the United States, they likely apply, proportionally, to Canada because the populations are similar. Estimates of the number of deaths from influenza and related respiratory conditions range in this country from 1,500 to 10,000 annually.
The new CDC figures suggest the correct number is likely 6,500 flu deaths and another 1,800 RSV deaths, making these common viruses among the biggest killers of people over the age of 65.
The newly published research shows that the most deadly respiratory virus is influenza A (H3N2), followed by RSV, influenza B and influenza A (H1N1).
In a related commentary published in today's JAMA, David Morens, of the U.S. National Institutes of Health, says the new mortality figures should tell policy makers that more effort has to be made to ensure those at greatest risk of influenza are vaccinated, in particular the "elderly elderly," those older than 85