LONDON : It is not yet clear whether the world needs a new set of vaccines to fight different variants of the novel coronavirus but scientists are working on new ones so there is no reason for alarm, the head of the Oxford Vaccine Group said on Tuesday.South Africa has paused a planned rollout of AstraZeneca's vaccines after data showed it gave minimal protection against mild infection among young people from the dominant variant there, stoking fears of a much longer battle with the pathogen.AstraZeneca and Oxford University aim to produce a next generation of vaccines that will protect against variants as soon as the autumn before the Northern Hemisphere winter, AstraZeneca's research chief said this month."There are definitely new.