LONDON, July 20: AstraZeneca’s experimental COVID-19 vaccine was safe and produced an immune response in early-stage clinical trials in healthy volunteers, data showed on Monday. The vaccine, called AZD1222 and being developed by AstraZeneca and scientists at Britain’s University of Oxford, did not prompt any serious side effects and elicited antibody and T-cell immune responses, according to trial results published in The Lancet medical journal.