Provided is a process, including: obtaining, with a computer system, a next geolocation to be visited by a user or at which the user has arrived; obtaining, with the computer system, a geolocation-pathogen-risk score of the next geolocation; determining, with the computer system, a topic of message based on the geolocation-pathogen-risk score; determining, with the computer system, by a natural-language-text generation model, natural language text within the topic of the message; and causing, with the computer system, the natural language text of the message to be presented to the user.