Andes Hantavirus human-to-human transmission dynamics and1 preparedness scenarios

Human-to-human transmission of the Andes virus (ANDV), which causes the deadly Hantavirus Pulmonary Syndrome, has been documented in several outbreaks, but remains insufficiently characterized to ensure preparedness against future emergence. Here, we integrate epidemiological data from historical outbreaks and from the 2026 MV Hondius outbreak with a stochastic network-based transmission model to quantify ANDV epidemic potential and control requirements. We estimate a reproduction number of $R_0=2.30$ (95\% CI: 1.33--3.27), supporting sustained human transmission. Uncertainty and sensitivity analysis show that variation in transmissibility and incubation period mainly affects outbreak timing and size, while superspreading events can substantially alter the epidemic evolution. Model analysis and simulations further reveal how contact-network structure strongly modulates outbreak size, with close-contact clustering facilitating containment. Due to the virus characteristics, rapid identification and isolation can effectively suppress outbreaks, even more effectively than in the case of COVID-19, whereas pre-symptomatic transmission or increased mixing could substantially increase risk. Our results provide a quantitative framework for ANDV preparedness and highlight the most critical transmission features for future surveillance.