# 2420
Over the past couple of years a number of studies have shown that the elderly develop a significantly lower immune response to seasonal vaccinations than do those who are younger.
I've blogged on a number of these studies, including:
Another Study: Flu Vaccines Do Not Reduce Mortality Rates In The Elderly
Study: Flu Vaccines And The Elderly
Flu Shots For The Elderly May Have Limited Benefits
Of the 36,000 flu-related deaths each year in this country, 90% occur in those over 65. Unfortunately, this is the exact cohort that seems to derive the least benefit from the standard flu shot.
Sanofi-Pasteur, the vaccines division of Sanofi-Aventis Group, funded a study conducted at 30 centers around the United States where several thousand people over the age of 65 were given a flu vaccine with 4 times the antigen of a standard shot.
Instead of 15ug of antigen per strain, these shots contained 60ug.
The results of this study were delivered today by lead researcher Dr. Ann Falsey, associate professor of medicine at the University of Rochester School of Medicine and Dentistry, to a joint meeting of the American Society for Microbiology and Infectious Diseases Society of America.
Those who received the stronger shot developed a significantly stronger immune response than those who received the standard dose.
Sanofi-Pastuer hopes to license the higher-dose vaccine for use in older patients here in the United States.
In the meantime, health officials continue to recommend that those over 65 get a flu shot each year.
While it appears true that the elderly mount a less robust response to the standard shot, it is still believed to provide some protection.
Here is the Sanofi-Pasteur press release (excerpted and reparagraphed for easier reading). Follow the link to read the entire article.
High-dose influenza vaccine shows increased immune response among adults 65 years of age and older
Washington, DC, October 26, 2008 - Sanofi Pasteur, the vaccines division of sanofi-aventis Group, announced today that an investigational high-dose influenza vaccine demonstrated increased immune responses among adults 65 years of age and older compared with the standard influenza vaccine. The candidate high-dose intramuscular formulation of the influenza vaccine is being developed by sanofi pasteur.
The results were reported today at the 48th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)/Infectious Diseases Society of America (IDSA) 46th annual meeting.
According to the U.S. Centers for Disease Control and Prevention (CDC), the currently available inactivated influenza vaccine offers public health benefits in reducing influenza-related morbidity and mortality in older adults.
Study authors explain, however, that as people age, the immune system tends to weaken. Older adults become not only more susceptible to infections, but also less responsive to vaccination. When infected with the influenza virus, they are less able to mount an immune response to neutralize the attack.
"Development of an influenza vaccine that will provide an improved immune response in older adults is important because this population has the highest rates of complications from influenza including hospitalization and death," said Ann R. Falsey, MD Associate Professor of Medicine, University of Rochester School of Medicine, Rochester, NY; Infectious Diseases Unit, Rochester General Hospital.
<snip>
In the randomized double-blind study conducted at 30 centers throughout the United States, 2,575 people received the high-dose influenza vaccine and 1,262 received the standard influenza vaccine.
The standard influenza vaccine contained 15µg of hemagglutinin (HA) of each of three influenza strains, and the high-dose vaccine contained four times as much, 60µg HA per strain. Both vaccines contained two influenza type A strains (H1N1 and H3N2) and one influenza type B strain.
After 28 days, investigators assessed serum hemagglutination inhibition (HAI) titers in study participants, a standard measurement of the immune response to influenza vaccination. HAI titers are thought by researchers to correlate with increased protection against illness after exposure to influenza.
Statistically significant higher HAI titers against all three influenza virus strains were reported in those who received the high-dose vaccine compared with those who received the standard vaccine.
