Are vaccinations without written consent a breach of human rights?
I would have to say that vaccinations without informed consent are against human rights if we define human rights as the rights of individuals who are competent to make decisions whether or not to be vaccinated. However, if the question is framed as inquiring about societal human rights, the answer is not so clear.
A vaccination is the introduction of a "foreign" substance into our bodies for the purpose of stimulating the immune system to withstand a particular disease. There are always risks to doing this, but statistically, the gains far outweigh the risks. The adult individual has the right to decline a vaccination, the individual human right to decide whether or not to take this risk. And the adult individual in many countries has the right to decide to make this decision on behalf of the minor child for whom he or she is responsible legally.
On the other hand, there is a societal human right at stake here, too, the right of the society to ensure or try to ensure that diseases are prevented where possible because everyone in a society bears the burden of taking care of its sick. There might not be a legal mandate to bear this burden in some societies, but the costs of illness are always high, no matter what, if only in lost productivity.
Presently, in the United States, these potentially conflicting interests are resolved state by state, with most states, as I understand it, requiring vaccination for children before they are permitted to enter school. (States, I believe, carve out a First Amendment exception for those whose religious beliefs preclude vaccination.) So the states are trying to protect the rights of society while trying to protect individual human rights. Children who are not vaccinated, absent this religious exemption, can be prevented from attending public schools. This is a sort of compromise, allowing people to decide that not having their children vaccinated is more important than their attending public schools, while providing that public school children, which used to be most children, are protected and cannot infect others in society at large.
The prevailing culture in the United States is a highly individualistic one, often coming down on the side of the individual against the rights of the society. This is what allows the unvaccinated to remain among us, endangering all of us and interfering with our societal rights. Here, the individual is free to disregard established medical knowledge and make a decision to not be vaccinated, to not vaccinate his or her children, a human right, to be sure, but a dubious one in my opinion.