Answer:
The main historical circumstance that has led to the infodemic related to current pandemic is that information technology, the internet, and social media, have spread so fast to a majority of the world population, that all kinds of information, from scientifically-backed claims, to pseudoscience or bogus claims, can reach a worldwide audience in very brief periods of time.
Because a large number of people do not have enough critical thinking skills, or only interact online with people that hold the same views that they do, misinformation can spread easily, and lead to the creation of conspiracy theories with millions of followers.