The primary cause of the decline of the mpox epidemic that spread in Italy between May and November 2022 was the massive reduction in sexual activity (60-90%) within the MSM (men who have sex with men) communities most at risk of infection. These are the findings of a study by Fondazione Bruno Kessler and the Ministry of Health in collaboration with Vita-Salute San Raffaele University, Indiana University, Northeastern University and the University of Florida, just published in the journal Nature Communications.