Hesitancy increased in the European Union after several countries in the bloc suspended use of AstraZeneca Plc’s vaccine because of concerns about blood clots. In an online survey conducted in April by Eurofound, 34% of respondents indicated they were unlikely to get immunized against Covid. Before the AstraZeneca pause, the figure was 25%. Skepticism was highest in Bulgaria, at 61%, and below 10% in Denmark, Malta and Ireland. According to U.S. census data as of late April, 12% of American adults were hesitant about getting a Covid vaccine, with the rate ranging considerably by state, going as high as 26% in Wyoming. In a survey across 19 countries in June 2020, before Covid vaccines became available, 72% of people said they would take a shot that proved safe and effective. The acceptance rate ranged widely among countries, from 55% in Russia to 89% in China. In an article in Nature Medicine, researchers wrote that in most of the countries, there was insufficient willingness to accept a Covid vaccine to meet the requirements for herd immunity.