London .- A Covid-19 vaccine being developed at Oxford University is safe and induces an immune response, according to the early stages of testing results published in a study.Results of clinical testing on 1,077 healthy adults without Covid-19 found the vaccine resulted in the creation of antibodies and T cells, the study published in the Lancet medical journal said.A sub-study of 10 volunteers suggested the vaccine, known as ChAdOx1 nCoV-19, was even more effective when a secondary booster dose was administered.It is being developed at unprecedented speeds given the global urgency for a vacc…