AstraZeneca said Monday that the Covid-19 vaccine it developed with the University of Oxford reduced both mild and serious forms of the disease, paving the way for a likely U.S. authorization of the vaccine. Doctors, regulators, and government officials the world over are likely to breathe a sigh of relief at the results, which are better than expected and appear materially higher than those in previous studies. The two-dose vaccine reduced symptomatic disease by 79%, the company said in a press release, and reduced severe Covid-19 and hospitalization by 100%. AstraZeneca said that the vaccine was equally effective in people over 65, where it had 80% efficacy.