Should child vaccinations for preventable diseases be made mandatory?

At the core of Liberalism is the belief that individuals should be as free as possible insofar as they don't cause significant harm to other people, and that Governments should only intervene to protect individual freedom and prevent significant harm to others. This raises various questions where vaccinations are concerned.

Not having a vaccination is potentially harmful to the individual who was meant to receive it. If that decision is taken by parents, then they may well be inflicting harm on their child by refusing. If the child is given the agency to take such a decision though, perhaps this removes our right to intervene in the decision?

On the face of it, this may well seem like a valid argument. Vaccinations however are communal in their nature. If enough people refuse a vaccination, the disease that we are seeking to prevent could well cause significant harm to the wider populace. Thus, refusing vaccinations may well cause significant harm to others.

That said, it's possible that we could establish a specific threshold below one hundred percent coverage at which a vaccination will still work. It's also possible that we might be able to prove that the level of psychological harm caused to a specific group by being vaccinated outweighs the potential harm to the populace of not having full coverage.

In the absence of such evidence though, we must conclude that failing to vaccinate individuals is likely to cause others significant harm. In such circumstances it is justifiable for Government to intervene by making vaccinations mandatory for all children.

These are the questions that the Liberal Democrats (and philosophers) grapple with when developing any policy and it's why we're so keen on evidence-based policy. I believe that mandatory vaccinations are justified based on the harm principle, but I'm no epidemiologist.