vaccines: my personal opinion. also scientific fact. *updated*

I have felt very strongly about the issue of vaccinations,which I know it is a hot button, very polarized topic.  As a scientist, and a microbiologist in particular, I know that vaccines are good.  I get the flu shot every year and would continue to do so even if the hospital I work for didn't require it (on penalty of being fired).  What I don't understand is that a little bit of conjecture suggesting a possible link between vaccines and autism (which has never been definitively proven) is enough to make a fairly sizable subset of the population decide against vaccinating their children.

Evidently, it's been so long since Americans have seen the effects of preventable diseases such as polio, measles, and rubella that people think their kids would never get these diseases.  In the past few years we in the hospital setting have seen outbreaks of Bordetella pertussis, or whooping cough, that can, in some cases, cause death.  Haemophilus influenzae is a potentially deadly bacteria that can cause pneumonia and meningitis and children under five should be vaccinated beginning at two months.  Even measles in very young children, elderly or immunocompromised patients can be deadly.

Some people believe in "herd immunity," which can be defined as providing a measure of protection against a certain infection in unvaccinated people when a significant portion of the population has immunity to that particular infection.  This logic is faulty for many reasons, but mostly because if more and more people decide not to vaccinate, herd immunity will no longer have a modicum of effectiveness (if it ever did).

If you choose not to vaccinate yourself, that's fine.  It's not you I'm worried about.  I'm worried about the infant you held when you didn't know you were coming down with the flu or the elderly person you stood in front of in line at the grocery store.  For this population of people, the flu virus can be deadly.  How about the pregnant lady who hasn't been vaccinated for rubella?  If she's exposed her baby can suffer from serious birth defects including heart problems, hearing or vision loss, intellectual deficiencies and liver and spleen damage.

I realize that not all vaccines are 100% effective, 100% of the time because everybody's immune system is different.  But why take the chance?

**UPDATE**
22 people in North Carolina have died of influenzae including one infant in eastern NC.  19 of the deaths have been young-middle aged people considered previously in good health.