Kai Kupferschmidt, Gretchen VogelScience’s COVID-19 reporting is supported by the Heising-Simons Foundation.A dozen European countries today said they will resume vaccinations with the AstraZeneca vaccine against COVID-19 after the European Medicines Agency (EMA) said its initial investigation of possible side effects has concluded the vaccine is “safe and effective.” Their decisions came as a relief to many public health experts, who worried about long delays in the COVID-19 vaccination programs at a time when cases are increasing in much of Europe.At a press conference this afternoon, EMA officials said their inquiry could not rule out a connection between the vaccine and certain unusual clotting and bleeding disorders, but they concluded.