Are flu vaccines always affective

Answer 1

It often does, especially for the seasonal flu strains that mutate easily and rapidly, but often make such small changes at each mutation, that they are still vulnerable to the immune system's antibodies produced for the original strain that the vaccine contained.

They will not help as readily (or at all) to prevent a different type or subtype of flu, but a change in the strain often does not negate the effectiveness of the antibodies created for a different but very similar strain.

This is partially how the epidemiologists choose the strains that they use to make vaccines for seasonal flus; they choose the virus strains that are most similar to the majority of the strains that are circulating in a population and expected to be primarily causing the next seasonal flu outbreaks. They plan on the strain they choose being similar enough to the majority of strain mutations that year to protect in a broader scope than just the one strain used in the vaccine.

Answer 2

No. While similar, all flu viruses are different and a vaccine must be made for each type. That's why it is very unlikely that the flu will ever be eliminated completely without a different approach to stop virus replication. Various studies to find a different approach are currently underway with some already offering very promising early results.

But until then, the annual flu vaccines are effective only against the specific influenza strains that have been determined to be most likely circulating in the upcoming flu season and have been included in the vaccines.

For the 2011-2012 flu season in the US, the Food and Drug Administration (FDA) announced the approval of six vaccines on July 18, 2011. These approved trivalent vaccines for the seasonal flu will all contain vaccine for the H1N1/09 "Swine Flu" and two other flu viruses suggested by CDC for this season.

The CDC-approved trivalent vaccines for this flu season will protect against the following three flu virus strains:

1. A/California/7/09 (H1N1)-like virus (A-H1N1/09 "Swine Flu" influenza virus)

2. A/Perth/16/2009/ (H3N2)-like virus

3. B/Brisbane/60/2008-like virus

The approved vaccine brands for the 2011-2012 flu season are:

1. Afluria (CSL Limited)

2. Fluarix (Glaxo Smith Kline Biologicals)

3. FluLaval (ID Biomedical Corporation)

4. FluMist (MedImmune Vaccines, Inc.)

5. Fluvirin (Novartis Vaccines and Diagnostics Limited)

6. Fluzone, Fluzone High-Dose, Fluzone Intradermal* (Sanofi Pasteur, Inc.)

*The Fluzone Intradermal is a new formulation for administration in the layers of the skin (intradermal injection) instead of the intramuscular (IM) injection. Fluzone Intradermal administration uses a microinjection system with a very fine needle. Approved for those aged 18 through 64.