Covid Live Updates: Mixing Vaccines Provides Strong Immunity, Study FindsPfizer and AstraZeneca work together well in a two-dose vaccination schedule; so do three doses of AstraZeneca, researchers find in separate studies.Covid Live Updates: Mixing Vaccines Provides Strong Immunity, Study Finds
Nearly 20 percent of the U.S. population is fully vaccinated. Many countries may not hit that target this year.The widening gap is fueling frustration and potentially extending the pandemic.Nearly 20 percent of the U.S. population is fully vaccinated. Many countries may not hit that target this year.