The U.S. Food and Drug Administration has authorized use of a second COVID-19 vaccine for people age of 18 and over, a move that will trigger the shipment of millions more doses to hospitals and nursing homes within days.
Like its competitor Pfizer, the Moderna vaccine was believed to be both safe and highly effective. After tracking some 30,000 volunteers, Moderna estimated it as 94% effective in preventing COVID-19 illness with few serious side effects.
