Longitudinal Observational Study of the Natural History of Andes Virus Infection

This is a longitudinal observational cohort study enrolling individuals with a defined exposure to Andes Virus (ANDV) who are confined or quarantined. Subjects can be included in one of the three tiers and are all followed from one tier to the other and/or to end of quarantine: (a) Tier 1 (Exposure/Enrolment): from X0/E0 to P0 (first RT-qPCR positive); (b) Tier 2 (Pre-symptomatic infection): from P0 to S0 (first symptom onset); (c) Tier 3 (Symptomatic disease): from S0 to clinical outcome (clinical resolution or death). Epidemiological information from their exposure (X0) is also collected. The overarching goal is to delineate the natural history and the virologic and immunologic mechanisms and consequences of infection with sampling intensity matched to biological inflection points, i.e., higher frequency around P0 and symptom onset (S0) and lower intensity elsewhere. Clinical care is not directed by the protocol. All medical decisions remain under treating clinicians. This protocol remains observational and purposely low-intensity because it does not direct clinical care, and uses a trigger-based, phase-adaptive tier structure (X0/E0, P0, S0) that limits biospecimen collection to fixed, low-frequency schedules (generally 1-2 collection days/week with step-down to 1 day/week in weeks 5-6 post-trigger) while daily follow-up is restricted to non-invasive clinical monitoring. Participation in the NAVIS protocol does not restrict or prevent enrollment in other Hantavirus-related emergency responses or interventional clinical trials.