Cost Effectiveness of Quadrivalent Influenza Vaccines Compared with Trivalent Influenza Vaccines in Young Children and Older Adults in Korea.

The use of QIV over TIV was estimated to not be cost effective in children 6-59 months of age, but cost saving in older adults, using the narrow definition of influenza; however, QIV use was cost saving in both age groups using the broad definition. QIV is expected to yield more benefits in older adults ≥ 65 years of age than in children aged 6-59 months due to higher influenza-related mortality and costs among the older adults. Further analyses considering the indirect effects of influenza vaccination in children are required.