Comparison of incidence and cost of influenza between healthy and high-risk children <60 months old in Thailand, 2011-2015.

Compared to high-risk children, healthy children had higher incidence of mild influenza-associated ARI but not severe influenza-associated ARI. Costs of severe influenza-associated ARI were substantial. These findings support the benefit of annual influenza vaccination in reducing the burden of influenza and associated cost in young children.