The latest on the Covid-19 vaccine sprint

Some important weekend vaccine updates: First, AstraZeneca has resumed the Phase 2/3 trial of its Covid-19 vaccine candidate in the U.K. The trial was paused after a potential adverse reaction to the vaccine in a participant, which appeared to be transverse myelitis, a serious condition involving inflammation of the spinal cord. But so far, the trial has only picked up again in the U.K. The company is also conducting Phase 2/3 and Phase 3 trials in the U.S., Brazil, and South Africa. “The Company will continue to work with health authorities across the world and be guided as to when other clinical trials can resume,” an AstraZeneca spokesperson told STAT.

And second, in a move that would allow them to collect more data and expand diversity among study participants, Pfizer and BioNTech are planning to enlarge the Phase 3 trial of their joint Covid-19 vaccine from 30,000 people to 44,000. The FDA needs to give an OK before the plan can go forward.