Compliance with multiple-dose vaccine schedules among older children, adolescents, and adults: results from a vaccine safety datalink study.

OBJECTIVES: We studied compliance with multiple-dose vaccine schedules, assessed factors associated with noncompliance, and examined timeliness of series completion among older children, adolescents, and adults. METHODS: We conducted a large, multisite, retrospective cohort study of older children, adolescents, and adults in the Vaccine Safety Datalink population from 1996 through 2004. We quantified the rates of completion of all required doses for varicella, hepatitis A, and hepatitis B vaccines according to their recommended schedules. RESULTS: Among those who received a first dose of varicella (n = 16 075), hepatitis A (n = 594 917), and hepatitis B (n = 590 445) vaccine, relatively few completed the series (55%-65% for hepatitis B vaccine and 40%-50% for hepatitis A and varicella vaccines in most age groups). Compliance was lowest among adolescents (35.9%) and Medicaid recipients (29.7%) who received varicella vaccine and among younger adult age groups who received hepatitis A vaccine (25%-35% across those age groups). Even among series completers, there was a relatively long interval of undervaccination between the first and last doses. CONCLUSIONS: Compliance with multiple-dose vaccine series among older children, adolescents, and adults is suboptimal. Further evaluations of strategies to improve compliance in these populations are needed.

Impact of the introduction of pneumococcal conjugate vaccine on rates of community acquired pneumonia in children and adults.

Pneumococcal conjugate vaccine use among young children has led to significant declines in invasive pneumococcal disease in the United States, but the impact on community-acquired pneumonia is unknown. We conducted population-based pneumonia surveillance among 794,282 Group Health members before and after infant vaccine introduction in 2000. We presumptively identified pneumonia episodes using diagnosis codes assigned to medical encounters and confirmed 17,513 outpatient and 6318 hospitalized events by reviewing chest radiograph reports or hospitalization records. There was evidence for a decline in rates of both outpatient and hospitalized pneumonia in children less than 1 year of age following vaccine introduction but there were no consistent reductions in pneumonia rates among older children and adults.