The U.K.’s decision to delay the second shot of the AstraZeneca-University of Oxford coronavirus vaccine has been found to be an effective strategy. Oxford researchers found that the Covid vaccine was 76% effective at preventing symptomatic infection for three months after a single dose. In fact, the efficacy rate rose with a longer interval between the first and second doses. The vaccine is also seen to lower transmission of the virus, a crucial factor in lifting lockdowns.