A disease with a long incubation period and moderate R0 begins circulating in a partially immune community. Synthesize an optimal combined strategy that addresses both early detection and protection of susceptible individuals.

• A. Combine expanded testing including asymptomatic contacts, prolonged quarantine windows that match the incubation tail, targeted vaccination drives for susceptible subgroups to raise local immunity, and enhanced contact tracing with digital support to capture presymptomatic transmission chains.
• B. Focus only on environmental decontamination of public spaces without any individual-level testing or vaccination, because environmental persistence is the only driver of outbreaks for diseases with long incubation periods.
• C. Rely solely on one-time mass screening at a single time point and immediate removal of symptomatic individuals from community settings, because long incubation makes ongoing interventions unnecessary once initial cases are identified.
• D. Implement broad lockdowns that permanently isolate the receptive fraction of the population while allowing unrestricted mixing among immune individuals, since selective quarantines invariably stop presymptomatic spread with no additional measures required.

Answer: (A)