Flu shot hoping to "trick" the oldster's immune system

When it comes to getting flu shots, seniors are exceptional.

Yet despite their unusually high vaccination rates, they also account for an exceptional portion of flu-related hospitalizations: 90 percent, according to the Centers for Disease Control and Prevention (CDC).

It turns out their bodies are sluggish to react to the standard vaccines that easily rev up a younger person's immune system.

So doctors around the country are hoping to coax a better immune reaction from seniors this flu season by offering them a shot that packs four times the amount of dead flu virus to which the body can react.

This high-dose shot, manufactured by French pharmaceutical giant Sanofi Pasteur, has been proved in clinical trials to get a stronger immune response, the CDC said.

Whether a heightened immune response reduces the number of seniors contracting the flu has yet to be proved.

That clinical trial won't be completed until 2014.

But Dr. Larry Bush, an infectious-disease specialist in Atlantis, Fla., gives the shots to patients 65 and older.

So do many private physicians, supermarkets and pharmacies, including Bartell Drugs.

The elderly can choose the standard vaccine or the high-dose one. When his patients ask which he would pick, Bush tells them, "If I were over 65, I would get the high dose," he said.

Bush said that while we can't yet prove it is significantly more effective, it's certainly not less effective. And, Bush said, he's inclined to believe that a proven rise in immune response will translate to fewer cases of the flu.

"It makes sense," said Bush, a staff member at JFK Medical Center in Atlantis, Fla.

Though the CDC at one time advised only select vulnerable populations — including the elderly — to get vaccinated for the flu, that advice changed in 2008. The standing message now is that everyone 6 months and older should get a shot.

It's a message that is particularly important to older people.

"They're at much greater risk of complications and death," said Dr. David Greenberg, Sanofi Pasteur's senior director of scientific and medical affairs. "Influenza, we often say, is not just a bad cold; it's a terrible disease that can lead to hospitalizations and death."

The contagious respiratory virus can bring on a fever, headache, sore throat and runny nose. The flu can make existing chronic medical conditions such as asthma or diabetes worse. It also can cause complications such as sinus infections and bacterial pneumonia.

Flu and pneumonia are the seventh-leading cause of death in the United States among those 65 and older, according to the most recent data from the CDC.

The high-dose vaccine was licensed by the U.S. Food and Drug Administration in time for last flu season. Sanofi Pasteur estimates that 10 percent of the elderly population that was vaccinated last season opted for the high dose. The option is more widely available this year, company officials say.

Like the standard shot, the high-dose version is made of three flu strains deemed most likely to make people ill in that season.

But the high-dose shots pack more antigens, those elements that trigger a body's immune response.

Sanofi's Greenberg said the higher dose of antigens also results in more reactions from the shot.

"The downside is there are slightly more local side effects," Bush said. "A little bit more redness, a little bit more tenderness (around the shot area), a little bit more fever."

But when it comes to serious side effects, the high-dose vaccine is no different from the standard, the CDC said. "Most people had minimal or no adverse events after receiving the Fluzone High-Dose vaccine," it said.