Influenza Vaccination of VFC Versus Non-VFC Children

Background:
Influenza vaccination presents unique challenges to the healthcare system, given that vaccine must be distributed and administered each year during a limited time interval. Previous studies have correlated early administration with higher compliance with the recommended 2-dose regimen for previously unvaccinated young children.

Objectives:
To prospectively capture data on influenza vaccination practices and behaviors in U.S. pediatric practices.

Methods:
Data describing influenza vaccination practices was collected from 42 US outpatient pediatric practices during the 2007–2008 influenza season and 98 practices during the 2008–2009 season. Influenza vaccinations were tracked every half-month interval for children based on age, participation in Vaccines for Children (VFC), and first or second vaccination.

Results:
During the 2007–08 season, 42,252 children were vaccinated, 11,239 (27%) of whom received VFC vaccine. Administration of VFC vaccine began approximately 1 month following commercial vaccine, but both VFC and non-VFC vaccinations declined similarly from early November forward. Compliance with the 2-dose regimen was lower in VFC vs. non-VFC children (39% vs. 48%); the greatest difference was in children 24-59 months (30% vs. 45%). Vaccination coverage for VFC vs. non-VFC children could not be calculated, as the total number of children eligible for VFC could not be accurately estimated. During the 2008–2009 season, administration of VFC vaccine was also delayed; data on 2-dose compliance will become available as the season progresses.

Conclusions:
In the fall of 2007 and 2008, administration of VFC influenza vaccines was delayed relative to commercial vaccines. Children receiving VFC vaccine had lower compliance rates with the recommended 2-dose regimen, possibly resulting from the delay in administration.