Russia claims to be the first country with a coronavirus vaccine that's cleared for use, but some scientists are having doubts.
Russian President Vladimir Putin said the vaccine went through all of the necessary tests to ensure it's safe and that even one of his daughters was given two doses and is doing well.
He emphasized that the vaccine will be voluntary and provides immunity for up to two years.
Scientists are expressing concerns as experts have warned rushing to use a vaccine before Phase 3 trials (involving thousands of people) could backfire.
BBC News reports that the World Health Organization asked Russia last week to follow international guidelines for producing a vaccine against Covid-19.