Q. Last year there was a minimal supply of the High-Dose influenza vaccine in our area. From an earlier column of Ask the Pharmacist, you mentioned that there are 2 vaccines that are targeted for the over 65 age group. Can you go into more detail about that?
A. Let us begin by admitting that last year’s influenza vaccine campaign was quite the debacle. With our Premier advocating that everybody should get their flu shot to prevent a Twindemic and that every person over the age of 65 should get a high-dose vaccine, that led to a higher demand than normal for any and all vaccines but, in particular, the eagerly sought high-dose version.
In previous years, the high-dose vaccines were limited to primary care providers (i.e. family doctors) and thus not sent to pharmacies to administer. Last year, however, pharmacies were given a supply (albeit small) of these high-dose vaccines along with the usual supply of the “regular” influenza vaccines. This supply was scant to say the least and our request (along with those of our peers) for more shipments were continually denied, leading to a lot of disappointed patients. Let us hope that this flu season will be handled better. For many of you that may wish to get the high-dose version, much will again depend upon availability. But rest assured, there is another influenza vaccine that is also geared specifically to the over 65-year-old crowd. It is called Fluad and it is an adjuvanted trivalent influenza vaccine (TIV-adj).
To explain this in more detail, let’s first describe vaccines in general. A vaccine contains an antigen from the virus that, once it is injected, will cause our body to begin a cascading series of effects that serve to educate various immune cells within us to protect against future encounters with the same virus.
First, a local inflammatory response is initiated and within hours immunocompetent cells are “drawn” to the site of injection where they pick up the injected antigen and migrate to draining lymph nodes where they educate T-cell and B-cell responses in the body. Unless you wish to have a university lecture to describe this in more detail, let’s suffice to say that what occurs is quite an interesting yet very complicated response.
As you may recall, as we mature with every birthday celebration past a certain point (peak immunity occurs somewhere at or between puberty and very early adulthood), it is believed that our body’s natural immune response begins to slowly dwindle. This, quite naturally, also effects our response to vaccines in a negative fashion. Hence, this is why the higher dose of influenza vaccine is manufactured and targeted specifically for seniors. The increased dose should prompt their immune systems to help make up for the deficit that comes with ageing.
If this year is anything like last season, this high-dose version will be in a much higher demand than what the supply will allow for. However, researchers have discovered long ago that adding a specific substance to the serum, called an adjuvant, will enhance the immune response to the vaccine in individuals, particularly in the elderly, as compared to the same vaccine without the adjuvant. Live vaccines do not require the use of adjuvants since they are adding a small dose of the actual virus into the body which will in effect give the body an adequate response.
Most vaccines, including the various influenza vaccines, are inactivated (not live) vaccines. Adding an adjuvant will not only improve the body’s immunity but it can also encourage a quicker response to the antigen (vaccine). There are numerous adjuvants that are added to various vaccines such as alum, AS04, MF59, AS01-B and CPG 1018. The one that is added to Fluad is MF59 which is an oil-in-water emulsion adjuvant. MF59 has been around for decades and is known to be both safe and well tolerated.
We do not know what the supply will be like this season for either the Fluzone High-Dose or the Fluad, which are the two influenza vaccines that are reserved exclusively for people 65 years-of-age and older. If you fall into this age demographic and discover that the supply of these special vaccines has been depleted, know that it is safe to get any of the other quadrivalent influenza vaccines that are available; FluLaval Tetra, Fluzone Quadrivalent, Afluria Tetra and Flucelvax Quad. These four vaccines are considered to be equal amongst themselves. Keep in mind that getting any of these vaccines will still give you excellent protection against the influenza virus and reduce your risk of getting seriously ill and require hospitalization. For more information on this or any other topic, contact your pharmacist.