Reply #161: but it's a tangent that doesn't support your correct point that no vaccine is 100% effective

[northernlights]

YOu are quite correct that no vaccine is 100% effective, but there are a number of reasons why:

One reason vaccines aren't 100% effective is because some people's immune systems have underlying (sometimes unknown) disorders that interefere with the vaccine's effectiveness. They simply don't develop a strong immune response.

Another reason is because, as in the case with HPV, there are many strains that can cause disease, but gardisil only protects against 3. The major 3, but only 3 of 40.

Another reason vaccines aren't 100% effective is because of the nature of some viruses to mutate so rapidly that the vaccine can become ineffective year over year.

Another reason vaccines aren't 100% effective is because, depending on the type of virus and the immune response to the virus, some immunity is only temporary -- as short as a few months before it wears off.

Herd immunity is totally irrelevent to this particular discussion of the vaccine's effectiveness or lack thereof due to the reasons I cited above. Also because it refers to causing immunity to the unvaccinated percentage of a population as well as the vaccinated and is used to prevent the rapid spread of infectious disease, such as flu pandemics. It simply doesn't relate in any way to the discussion.