Introduction: Recent studies confirm that influenza vaccination confers health benefits and reduces direct and indirect costs associated with the illness. However, these studies did not examine the situation in southern China, a hypothetical influenza epicentre for the emergence of pandemic influenza viruses.
Methods: Surveillance data were collected in Hong Kong in 1993/94 and used economic model was used to estimate the medical and social costs associated with influenza-like illness (ILI) and to predict the cost-effectiveness of implementing an influenza prevention programme.
Findings: The estimated ILI incidence was 110/1000. It was highest in those between 1 and 25 years of age while the rate of hospitalization was highest in the elderly. Influenza occurred throughout the study period, which was a mild influenza year. The model predicted more than 660000 ILI cases in a non-epidemic year, in which influenza B virus predominated, with an average ILI-associated cost of HK$283/case (US$36) and vaccination-associated costs of HK$74 (US$9.50) per vaccinated individual.
Conclusion: The medical, social and monetary costs of ILI in Hong Kong were not observed to be large when compared with those in more developed countries where there is a clearly defined influenza season and recognized disease burden. From the perspective of a susceptible individual, the vaccine was cost-effective but from the perspective of society it was not, even with the most cost-effective strategy of targeting the elderly. However, if the vaccine were effective in controlling newly emerging and highly virulent strains, targeted vaccination programmes might be highly cost-effective.