Dear Doctor: My husband and I have two teenagers, and we also take care of my 80-year-old mother. The kids and my husband and I all got our regular flu shots, but I just read about a new flu shot that's for people who are over 65. Why do older people need a different flu vaccine? Does it really work?
Dear Reader: You're referring to Fluzone High-Dose, which, as you say, is licensed specifically for individuals who are 65 and older. Like all flu shots, it works by priming the immune system to defend itself against the specific flu strain that the vaccine is targeting. This happens because a flu shot contains antigens, which are the uniquely shaped proteins found on the surface of a flu virus. When you get a flu shot, your immune system responds to the presence of those antigens by generating antibodies, which are your body's first line of defense against infection. It takes about two weeks after you get your flu shot for the antibodies to develop. Once that happens, you have an additional layer of protection against the virus in the vaccine.
The Fluzone High-Dose vaccine contains about four times more of the flu antigen than does the standard dose vaccine that you, your husband and your children got. That means the high-dose vaccine will generate a more powerful immune response. The reason this is important for older individuals is the fact that as someone reaches his or her mid- to late 60s, their immune system becomes weaker. The immune system becomes less effective at protecting the body from infection, and it no longer responds in a robust way to vaccines. That means that not only are people in their mid-60s and older more susceptible to becoming infected by the flu virus, they are also less able to build up the needed antibodies in response to a flu shot.
In a study mandated by the Food and Drug Administration to assess the safety of the new high-dose vaccine and to gauge how well it works, it was found to be 24 percent more effective than the standard-dose vaccine at preventing the flu among people 65 and older. In addition, there appeared to be a measurable reduction in serious complications among those individuals who did contract the flu. Those complications, which are often life-threatening, include pneumonia, inflammation of the heart, a worsening of existing heart disease and COPD, or chronic obstructive pulmonary disease.
At this time, the high-dose flu vaccine is specifically approved for older patients. In our practices, we are giving the high-dose flu shot to all of our patients who are 65 and older. However, if a high-dose vaccine is not available, it's important not to delay getting a flu shot. An advisory from the Centers for Disease Control and Prevention states: "No preference is expressed for any one vaccine type. Vaccination should not be delayed if a specific product is not readily available."
Bottom line: Everyone 6 months of age and older should get a flu vaccine, this season and every season.
(Send your questions to firstname.lastname@example.org, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)