Many viruses are capable of causing a slow infectious process in humans and animals under certain conditions. New "heroes" still continue to appear in the world of viruses. They cause legionnaires' disease, Ebola, hepatitis, Marburg fever, AIDS, mad cow disease and cover the world with the COVID-19 pandemic... New data on the causative agents of slow infections, on the scale of their spread throughout the world and development mechanisms, as well as, most importantly, on measures to prevent these deadly diseases tells an outstanding virologist, doctor of medical sciences, professor V. A. Zueva.