BALTIMORE — A flu vaccine designed specifically for the elderly is being tested at the University of Maryland and four other sites nationwide in an effort to increase the effectiveness of the inoculations.
The current vaccine is effective in 30 percent to 70 percent of older persons, said Dr. Robert Edelman, the study’s principal investigator.
“That’s not too good,” Dr. Edelman said. “In young adults, it’s 70 to 90 percent, so there’s a very big difference there.”
The difference is particularly important because the elderly are at an increased risk for death and serious side effects from the flu, Dr. Edelman said.
The federal Centers for Disease Control and Prevention in Atlanta reports that about 36,000 people die of the flu and 200,000 are hospitalized each year in the United States.
Most of the 36,000 deaths are among the elderly, and vaccination programs have focused on them and other high-risk groups.
About 100 volunteers older than 65 are being recruited for the local study, said Dr. Edelman, a professor of medicine and pediatrics at the University of Maryland School of Medicine and a researcher at the university’s Center for Vaccine Development.
The vaccine being tested has four times the concentration of dead flu virus in each dose, no preservative or gelatin stabilizer, and a lower amount of an egg protein than the vaccine that currently is licensed, Dr. Edelman said.
Study participants will receive either the new vaccine or the currently licensed flu vaccine, both made by Sanofi Pasteur.
Volunteers are being given a health screening before receiving the shot and also are having blood drawn. Twenty-eight days after receiving the shot, they will have blood drawn again to determine their immune response to the inoculation.
Why the elderly seem to respond better to a higher concentration is not known.
The immune system has a memory of sorts, and the elderly seem to respond well to viruses to which they have been exposed previously, but have more trouble with new viruses, Dr. Edelman said.
“What we don’t know is how long that memory will last,” Dr. Edelman said. “The fact they don’t respond too well would suggest to me the memory response is there, but it doesn’t last a long time.”
In addition to the University of Maryland, the study is being conducted at Baylor College of Medicine in Houston, Cincinnati Children’s Hospital Medical Center, St. Louis University Health Sciences Center and the University of Iowa.