Household-based costs and benefits of vaccinating healthy children in daycare against influenza virus: results from a pilot study.

BACKGROUND

Vaccinating children against influenza virus may reduce infections in immunised children and household contacts, thereby reducing the household-based cost associated with respiratory illnesses.

OBJECTIVE

To evaluate the impact of influenza virus vaccination of daycare children on costs of respiratory illnesses of the children and their household contacts from the household and societal perspective.

STUDY DESIGN

Cost analysis of data from a randomised controlled trial covering the period November to April of 1996-7 and 1998-9. Children (127 in 1996-7 and 133 in 1998-9) from daycare centres in Californian (USA) naval bases received influenza virus vaccine (inactivated) or hepatitis A virus vaccination.

OUTCOME MEASURES

Direct and indirect costs (1997 and 1999 US dollars) of respiratory illnesses in households of vaccinated and not vaccinated daycare children, excluding the cost of vaccination.

RESULTS

There were no statistically significant differences in household costs of respiratory illness between households with or without influenza virus-vaccinated children (USD 635 vs USD 492: p = 0.98 [1996-7]; USD 412.70 vs USD 499.50: p = 0.42 [1998-9]). In 1996-7, adult and 5- to 17-year-old contacts of vaccinated children had lower household costs than contacts of unvaccinated children (USD 58.50 vs USD 83.20, p = 0.01 and USD 32.80 vs USD 59.50, p = 0.04, respectively), while vaccinated children 0-4 years old had higher household costs than unvaccinated children in the same age group (USD 383 vs USD 236, p = 0.05). In 1998-9, there were no differences within individual age groups. Results from societal perspective were similar.

CONCLUSIONS

Overall, from both the household and societal perspectives, there were no economic benefits to households from vaccinating daycare children against influenza virus. However, we found some over-time inconsistency in results; this should be considered if changing recommendations about routine influenza virus vaccination of healthy children. Our study size may limit the generalisability of the results.