In Europe, several countries have suspended the use of the AstraZeneca vaccine. Berlin bureau chief Loveday Morris says reports of life-threatening blood clots have brought the vaccine under review by the World Health Organization and the European Medicines Agency, though the WHO has said the vaccine’s benefits outweigh the risks. Wellness reporter Allyson Chiu explains how scientists are determining whether there’s a connection between the rare blood clots and the vaccine, or if it’s just a coincidence.