Date Time AstraZeneca vaccine better when given 12 weeks apart This is an excerpt from an article which was first published on the ABC News website. Click to read the original article. Waiting three months between the first and second dose of the AstraZeneca COVID-19 vaccine results in high efficacy, backing current recommendations from Australian authorities, new research shows. Key points: Research in The Lancet shows the first of the two jabs offers 76 percent protection The vaccine uses new technology, so more research is expected to come The study, which involved more than 17,000 participants and was published recently in The Lancet00432-3/fulltext “The Lancet journal”), found the vaccine – which most people in Australia will receive – had an 81 per cent efficacy rate when a second dose was given three months after the first.