Input data for age-dependent probabilities.

aNo difference in input values between healthy and at-risk populations. bIdentical for influenza A and B. c97.0% present to a GP and 3.0% to A & E, in all age groups [23]. dNo difference between cases presenting to GP or A & E, or not seeking medical advice. eRisk of death assumed to be the same for all complications. A&E, accident and emergency; GP, general practitioner.