This article asks whether the Dalai Lama abandoned fundamental Buddhist ethical principles in vaccinating Indian infants.
The concept of doing no harm is fundamental to Buddhist teaching, as it is within other Indian religions (Hinduism, Jainism), and is known as ahimsa, literally "the avoidance of violence – himsa." One would not, for example, justify killing an animal in order to save one's own life, which is one reason why Buddhists are vegetarians.
Nor would one justify the killing of one child in order to save 1,000,000, as is often done by regulators in evaluating the costs/benefits of vaccines (which are known on rare occasion to maim or kill) to society as a whole. Simply, do no harm. This principle is no more open to negotiation to a Buddhist than Jesus being the Son of God is open to negotiation to a Christian.
The Dalai Lama himself once said
If you can, help others; if you cannot do that, at least do not harm them.