Timing of the Availability and Administration of Influenza Vaccine Through the Vaccines for Children Program

Background: Influenza vaccine must be distributed and administered each year during a limited time interval. To our knowledge, no previous studies have simultaneously evaluated the delivery and administration of privately purchased vaccines and influenza vaccines acquired through the Vaccines for Children (VFC) program. Methods: A prospective, observational study was conducted in US outpatient pediatric offices, tracking all influenza vaccinations during the season by age group, first or second vaccination, the child's need for 1 or 2 doses, type of vaccine, and VFC status. Results: A total of 42 and 84 practices completed the study in 2007 to 2008 and 2008 to 2009, respectively. In both seasons, initial shipments of VFC influenza vaccine generally arrived 4 to 5 weeks later than non-VFC shipments; VFC vaccine administration also started 1 month later than administration of privately purchased vaccine. Vaccine administration peaked in early November and late October in years 1 and 2, respectively, and declined rapidly thereafter. Overall, approximately one-half of all children who required 2 doses of vaccine were estimated to have received 2 doses. In both years, 2-dose compliance rates in the VFC population were 17% to 19% lower than those in the non-VFC population, possibly resulting from the VFC population's shorter time interval for second dose receipt. Conclusions: The VFC program is critical to ensuring financially vulnerable children have access to vaccination. Manufacturers, distributors, and public health officials should deliver VFC influenza vaccine to providers as quickly as possible. Pediatric healthcare providers should increase efforts to vaccinate all populations, especially the VFC population, in later months.