Professor Philip Nolan:

It is important to look at it in two ways. First, there is the reduction in mortality risk, that is, the risk of people dying. There is an important milestone when people over 70 are effectively protected and at that point one sees a radical reduction in the likelihood of people dying. Some people who are younger than 70 remain at risk of mortality and there is a much wider risk of hospitalisation but the effect of vaccination is progressive. If half of the adult population were vaccinated, the virus would find it twice as difficult to transmit. I do not think-----