@D Hall:

If you look up some texts on epidemiology (how diseases spread, vectors, the necessary ratio of immunized-to-non-immunized etc.) you'll see that unvaccinated people do pose a health risk to others. Yes, you may be a risk for babies or others like you who could not be vaccinated for medical reasons like allergic reactions. But more importantly, other non-vaccinated people may be a health risk to you -- because they may carry diseases to you that you're not protected against (they may already have symptoms of the disease, or they may not still have it but develop them later, or they may be 'Typhoid Mary's). It may be that the actual risk is low -- but this is mostly due to the fact that most other people are vaccinated and will thus not pose a threat to you (hence the 'Free Riders' that StCheryl above uses instead of 'Parasites' for unvaccinated people -- they are taking advantage of the fact that others took the 'risk' of vaccinating themselves.)

@Back of Beyond:

I think the idea is to get as many people vaccinated as possible as early as possible. There are, however, people who should not be vaccinated because of allergic reactions (like D Hall above) or other possible health problems -- that was apparently the case for your daughter. The doctor was right, and your daughter should later on be checked so that the reason for her bad reaction can be assessed (perhaps there is another way to immunize her in the future, and perhaps there isn't). You are right in assuming that this is not parasitism or even 'anti-vaccin'ism; it's simply a normal reaction to a complication. But the point is that some people with children who do not have any reactions to vaccins are still sometimes choosing not to vaccin them. If sufficiently many people do that -- and the percentage isn't that big, I think about 20% of the population -- then the diseases in question may come back. And be a problem for your daughter. (In fact, even with far less than 20% non-vaccinated people, your daughter might still be in danger if she came into contact with a non-vaccinated person who had been exposed to the respective diseases.) As Michelle1971 put it, your daughter should indeed not be vaccinated -- but everybody else who can without complications, should be.

@cblakey:

As far as I know, asthma is caused by a combination of environmental and genetic factors; absolutely no connection with vaccins has been shown (so your first born might have developed asthma without the vaccins anyway, as soon as he got exposed to a triggering allergen). Of course not everything is understood about it, but jumping to the conclusion that the vaccin was the trigger may not be the right thing to do. And again, even if it was -- even if it is 100% sure that the vaccin caused the allergic reaction in your baby, still youd would be in the same situation as Back of Beyond above: your baby should not be vaccinated, but everybody else should be for your baby's protection. As for autism, note that no connection has been shown between vaccins (or in fact between chemicals in general) and autism; note also that most cases of autism start around age 2, after what looked like perfectly normal development. It may be that your son would be autistic anyway, which is the case for most other people.

Now, to all of you: certainly there should be more research on the effects that vaccins might have on genetically predisposed people. Please let's know more about that, so that potentially problematic individuals can be identified as soon as possible. But frankly, as many people as possible should be vaccinated, or else old diseases will again become a frequent danger in everyday life. Not vaccinating as many people as possible would be like saying that, since car accidents do happen and many people die in them, people should stop learning to drive.