when we speak to a member of the government s sage environmental modelling group dr sean fitzgerald. britain may follow israel and germany in approving the rollout of a fourth covid i9 vaccine. thejoint committee on vaccination and immunisation will look at data on protection from three jabs and hospitalisation from the new 0micron variant, before making a decision on a second booster. professor anthony harnden is deputy chair of the jcvi. we need to see more data on whether there is waning immunity after the third dose of vaccine, and we also need to see whether there is an increased hospitalisation risk months after the third dose ie, the booster dose of the vaccine. so, there s quite a lot of data we need to review before we make any decision on a fourth dose. and of course, any decision about that will be based on the epidemiology that s the frequency of distribution of this virus at that particular time, and whether variant vaccines