White House launches ‘surge response’ teams to delta variant hot spotsThe highly transmissible variant remains the "greatest threat" to the U.S. coronavirus response, officials warn.White House launches ‘surge response’ teams to delta variant hot spots
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