Influenza: Whats Old? Whats New?
Our current influenza vaccine is produced based on technology that goes back to the 1950’s. Hens eggs are inoculated with a reformulated strain of influenza based on the most recent strains circulating. Essentially a new vaccine is created each year. The immunity it produces does not last beyond one influenza season. The manufacturing process is slow and fraught with potential problems. One inoculated hens egg produces one vaccine dose.
Efficacy of the influenza vaccine is less than what is desired, although efficacy is a difficult feature to measure. The best guess is that the vaccine will prevent influenza in 50-70% of people who receive it. It is possible that it decreases the severity of illness in those that do later catch influenza and become ill. The vaccine is considered safe. We have over 50 years of experience using it and adverse effects are infrequent and/or minimal.
There are about 10 influenza vaccines commercially available. The majority are lumped into what used to be the “TIV “category, which stands for trivalent inactivated vaccine. Last year TIV is replaced by “IIV’ which stands for Inactivated Influenza Vaccine. They vary in the age group for which they are approved, route of administration (intramuscular vs. intradermal), stabilizing additives, and other features. There is one “LAIV”, which stands for live-attenuated influenza vaccine. This is Flumist, which is given intranasally and is indicated for healthy persons aged 2 through 49.
What is new in influenza vaccine science is cell culture technique of vaccine production. The cell culture vaccine is a process combining newer discoveries in cell biology science. It allows for a quicker production of vaccine, which would be very helpful if there is a pandemic (that is a widespread, severe influenza season). The FDA licensed the first cell culture influenza vaccine last year.
What is needed is a “Universal Vaccine” for influenza. This is a vaccine producing immunity to a segment of the influenza virus that is consistently seen year after year. We have vaccines for other viruses that produce immunity that lasts for many years, why not for influenza? This research is being pursued and hopefully a candidate vaccine will be tested in the next several years.
For the 2014-2015 influenza season, Infectious Disease Services of Georgia will continue to provide the standard IIV (TIV) vaccine given by intramuscular injection. This inactivated material contains no live virus. A 2 page Influenza Vaccine Information Statement (produced by the CDC) is provided at the time of immunization to give more information on the vaccine. Any questions can be answered by the nurse at the time of injection. Everyone over age six months should get their yearly flu vaccine.
The CDC reported in the first week of December, 2014 that one of the 2 Influenza A strains in this year’s vaccine was not a good match. That is, there is an influenza A strain present in the community infecting people and causing illness despite people being vaccinated. This would apply to all vaccines this year, not just the one offered at our office. At the moment, the illness caused by this strain is not thought to be worse than other influenza strains. Vaccine efficacy is thus further diminished, perhaps to 50%.
What does this mean? We still believe people should receive the vaccine. Other inluenza strains (the other influenza A strain and influenza B strain) are covered by the vaccine. Also, there still may be some protection against the A strain that has “drifted” to a somewhat different structure. It does point out the need for a more universal vaccine that can consistently provide protection. Hopefully that will come in the next few years.
Please don’t forget or put off getting vaccinated! Influenza is a nasty illness, and some years, a life-threatening one. We recommend our patients be vaccinated for influenza. Please read more at the links provided below.
Visit www.cdc.gov as it provides useful information about influenza symptoms, disease, and treatment.
Please call and make a nursing appointment for vaccination.