BACKGROUND:
Pneumococcal conjugate vaccine (PCV) was licensed in February 2000 and recommended for use in infants and young children in October 2000. Beginning in August 2001, demand exceeded supply and interim recommendations were published to withhold vaccine for healthy children over two and to defer some doses for healthy children less than two.

OBJECTIVE:
To demonstrate the use of registry data to evaluate the catch-up of children who missed PCV7 doses during the shortage period.

METHOD:
Data from the Michigan Childhood Immunization Registry (MCIR) were used. Vaccine records were abstracted for children born between Jan 2000 and Aug 2002. Children were classified into pre- vs post shortage cohorts based on PCV3 coverage at 7 months of age. Timing of PCV dose 3 is described for the post shortage cohort. Coverage for PCV3 at 24 months of age in children who received dose 2 before 24 months is compared for pre- vs post- shortage cohorts.

RESULT:
Timing of dose 3 of PCV7 for the post-shortage cohorts suggests effort to recall children following resumption of supply in April of 2003. Coverage for PCV3 at 24 months of age was 70% in pre-shortage cohorts versus 63% in the post shortage cohort.

CONCLUSION:
Despite effort to recall children for whom PCV7 dose 3 was deferred during the shortage, coverage for 3 doses by 24 months of age was significantly lower in the post-shortage cohort as compared to the pre-shortage cohort.

LEARNING OBJECTIVES:
To learn how to use registry data to evaluate the impact of vaccine shortages.