Let me explain a bit about vaccination re point 3.
The person vaccinated will develop immunity to measles (let's assume measles jab in this example)
But the anti disease part goes beyond that 1 person being protected: With a high number of immune people it is far harder for the disease to spread, thus high vaccination rates ("herd immunity") act to stop disease spread & taken to the extreme it is possible to eradicate diseases (e.g. smallpox) that are dependent on human host for reproduction if they fail to reproduce for long enough
If insufficient herd immunity then easier for diseases to spread thus risking the lives of the non vaccinated.
Worth noting that young babies are at high risk as more likely to be die / be nastily affected by the disease when young and below minimum age to receive vaccinations (minimum age varies depending on the vaccination), plus some vaccines need boosters over time for full protection, so the main thing protecting the unvaccinated / not fully vaccinated youngster is herd immunity.
Anti vaccination is a position that can only readily come about in the scenario where vaccination has been effective and lots of nasty baby killing diseases are at a low incidence level & so the perceived risk from measles etc is low.
If some of the diseases currently vaccinated against start making a strong comeback anti vaccination folk might start to see why these diseases caused dread amongst parents in previous generations & why vaccination is a public health policy in countries that can afford it.
So refusing vaccination is detrimental to society as a whole as vaccination is about more than 1 persons immunity, it is about the common good.