Learning Objectives for this Presentation:
By the end of the presentation participants will be able to:
1. Define adolescent subgroups recommended to receive Menactra™
2. Describe uptake patterns of Menactra™


Background:
Menactra™, a new vaccine to prevent Neisseria meningitidis infections was licensed in January 2005. To balance projected vaccine production with optimal uptake, in February 2005, the Advisory Committee on Immunization Practices recommended vaccinating at the preadolescent health-care visit and before high-school entry, as well as persons at increased risk including college freshman living in dormitories. In July 2005, the manufacturer reported inability to meet demand.

Objectives:
Examine Menactra's™ uptake patterns among adolescents.

Methods:
VSD is a collaborative project between CDC and eight managed care organizations (MCOs). We analyzed 2005 data from five MCOs for adolescents aged 11-16 years (N= 619,371), estimating cumulative vaccination coverage by age. Data necessary to identify persons at increased risk (e.g. college freshman) are unavailable. We compared uptake among 11- to 12-year-olds (preadolescent health-care visit) and 14- to 15-year-olds (before high-school entry) to 13- plus 16-year-olds.

Results:
All five MCOs experienced a rapid increase in vaccination uptake among all three age groups between May and August followed by a rapid decline to a relatively steady rate by September 30. For all sites combined, at the end of 2005, the cumulative coverage for ages 11-12, 14-15, and 13- plus 16-year-olds was 12.3%, 10.7%, and 8.2% respectively; the risk ratios for receiving Menactra™ for ages 11-12 and 14-15 years compared to 13- plus 16-year-olds were 1.49 (95% Confidence Interval (CI): 1.46-1.52) and 1.29 (95% CI: 1.27-1.32), respectively.

Conclusions:
During 2005, the amount of Menactra™ administered to adolescents 11-16 years of age between May and August exceeded expectations. Recommended age groups were more likely to be vaccinated but the rapid uptake and vaccination of all three age groups likely contributed to the vaccine supply and demand mismatch.