Influenza vaccination allocation in tropical settings under constrained resources.

Influenza exhibits strong annual seasonality in temperate countries, but less consistent and predictable patterns in tropical countries. Many tropical countries are low-income countries with low influenza vaccine coverage. Globally, influenza vaccines are recommended for elderly adults and vulnerable groups, though evidence has shown that vaccinating school-age children is beneficial due to their high rates of social contact. Our modeling study evaluated whether age-based vaccine allocations can effectively minimize population influenza mortality in a tropical country with constrained resources and little seasonality. Prioritizing school-aged children for vaccination minimized mortality, with secondary emphasis on elderly adults. These benefits are most apparent under low vaccine supplies and can inform most effective ways to develop or expand influenza vaccination campaigns in low-income tropical settings.