In much rarer cases, some people have an allergic reaction soon after a vaccination. This is usually a rash or itching that affects part or all of the body. The GPs and nurses who give the vaccine are trained in how to treat this.

Ok so this is in the area of why we didn't vaccinate. As much as GP and nurses are trained to recognise and treat reactions to these medicines, your average person is not. There is evidence that vaccinations are associated with a higher rate of SIDS in a population, as a result of this.

That's why the hur hur antivaxxers are morons or the autism strawman argument are so flaccid. People have real and legitimate worries. Top it with hur hur get your kids jagged or get deported/denied education/ don't go to tesco.

Most militant pro vaccinators (who seem to mostly be 16-30, male, single, and childless by the way) just come across as not worth engaging with.

And the Risks of not taking Vaccines?

Well your child runs the risk of catching Mumps, Measles or Rubella (Assuming we're talking about the MMR vaccine here) which can also spread to unvaccinated children, or babies who aren't old enough in order to be vaccinated.

~95% of the population need to be vaccinated for herd immunity to be established. If your Child CAN be vaccinated (I.e. is of good age and has no medical reason not to) then your child SHOULD be vaccinated, as there are a small amount of people who CAN'T. Not getting vaccines lead to a measles outbreak in the USA as recently as LAST MONTH.

Horrible and selfish as it sounds, I make decisions for the benefit of my children, not others. I think you'll find when you grow up a bit that this is what most adults do.