Britain's AstraZeneca said on Monday its vaccine for the novel coronavirus could be around 90% effective without any serious side effects, giving the world another important tool to halt the COVID-19 pandemic. The combined analysis from both dosing regimens resulted in an average efficacy of 70%. The vaccine developed by Oxford University was 90% effective in preventing COVID-19 when it was administered as a half dose followed by a full dose at least one month apart, according to data from the l