Australia's Covid vaccines: everything you need to know

Analysis: As pharmaceutical companies release trial results, many questions remain about controlling coronavirus. Here is what we know

Around the world about 200 Covid-19 candidate vaccines are being developed, with more than 40 in human clinical trial stage. The Australian government has agreements to secure four of the most promising vaccines, and will roll them out if they prove to be safe and effective.

All four vaccines require two doses, spaced a few weeks apart. As the pharmaceutical companies behind some vaccine candidates begin releasing results, many questions remain about the next steps towards controlling Covid. Here is what we know. .