Studies suggest AstraZeneca COVID-19 vaccine safe, effective

New results on a possible COVID-19 vaccine from Oxford University and AstraZeneca suggest it is safe and about 70% effective, but questions remain about how well it may help protect those over 55 — a key concern for a vaccine that health officials hope to rely on around the world because of its low cost, availability and ease of use. Still, experts say the vaccine seems likely to be approved, despite some confusion in the results and lower levels of protection than what some other vaccine candidates have shown.