Open, honest communication about both the positive and potential negative effects of vaccines helps to foster trust in health authorities and increases the public’s acceptance of vaccines, according to a large study in the United States and Denmark. Researchers found that while openly talking about negative side effects initially reduced people’s willingness to be vaccinated, that reaction could be overcome by further discussions of the risks and benefits. But vague or reassuring communication that played down the negative aspects tended to lower acceptance of the vaccines, fuel conspiracy theories and reduce confidence in health authorities. Cause of vaccine-induced blood clots identified