Can the Childhood Influenza Vaccination Season Be Extended Beyond December: Lessons Learned From the San Diego Influenza Coverage Enhancement (SDICE) Study

Background: Influenza vaccination rates nationally remain much lower than rates for routine pediatric immunizations. The delivery of the influenza vaccine presents unique challenges as it requires yearly administration in a short time frame. Although the majority of influenza vaccinations are administered October-December, the peak of cases often occurs in February.

Objectives: Evaluate the effectiveness of implementing an academic detailing intervention to increase vaccination rates, particularly late season (January – March).

Methods: Parents of children 6-60 months were recruited and interviewed during the 2008-2009 (n=788) influenza season in 6 medical clinics. Intervention clinics received an academic detailing visit from the study staff medical director who discussed clinic immunization rates and promoted the adoption of selected evidence based practices to improve immunization rates; including vaccination during late season. Recruitment and interviewing the follow up year took place during the 2010-2011 (n=717) influenza season.

Results: 788 and 717 subjects were enrolled in the baseline and follow-up years, respectively. The overall influenza vaccination rate of the intervention group significantly increased by 7.7% (2008-2009: 55.4%, 2010-2011:63.1%, p=0.03). The control group vaccination rates were not significantly different across study years (2008-2009: 73.0%, 2010-2011: 77.4%, p=0.16). Furthermore, in the follow up year the intervention group experienced a borderline significant increase of 8.5% in late season vaccination rates from baseline (p=0.05). The control group experienced a 4.4% increase in late season vaccination rates from baseline however, this was not significant (p=0.24). In the follow-up year, 81.7% of intervention group parents reported receiving a mailed or telephone reminder for needed flu vaccines for their children from their respective medical practices; a 6.3% increase over baseline. Control group parents reported only a 1.6% increase in receipt of reminders over baseline.

Conclusions: Overall influenza vaccination rates increased significantly, as did late season vaccination rates, as a result of the academic detailing intervention.