Germany’s coronavirus deaths reached a record and Chancellor Angela Merkel extended restrictions, warning of possible travel curbs to keep out new strains. A study on the South African variant raised concern about the efficacy of vaccines as well as a new class of therapies. Scientists found that half of the blood samples from a handful of patients who already had Covid-19 don’t have the antibodies needed to protect against the new strain, which is spreading around the globe.

U.S. deaths topped 400,000, the world’s worst Covid-19 toll. An appointee of President-elect Joe Biden said the U.S. is preparing to join Covax, a World Health Organization-led coalition aiming to distribute vaccines to poorer nations. Daily fatalities in Mexico hit a record.

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