recently announced preliminary results showing their vaccines appear more than 90% effective, at least for short-term protection against COVID-19.
If those early results hold up and U.S. regulators agree the shots are safe, emergency use of small, rationed supplies could start in late December.
Other countries with contracts for early doses would undertake their own reviews.But multiple vaccines will be needed to meet global demand and help end the pandemic, raising concern that studies that still need to sign up thousands of volunteers could run short if people wait for an already OK'd option instead.“We don’t want to see that happen,” said Dr.