contributes to a 1r line website: When a viral crisis occurs, it is not only the viruses that spread with their own mechanisms, but it is also every society that unleashed its viral potential, according to a very common social operation that Tarde thought of imitation at the end of the 19th century. Because warning or support messages on social media, good practices, fears, fake news, everything spread according to a virality model, which should rather be called a replication principle, because, like viruses, what is transmitted is transformed and not always replicated in identity. All these forms of propagation occur at a high rate, at a high frequency and are in competition with each other. Thus, virus specific propagation mechanisms must be counteracted by the ability to spread health recommendations. Either on the basis of a disciplinary model in China, or (and even in the case of China) by virtue of imitation, a basic social process, which was so neglected despite the work of Tarde.