Effect of Vaccine Shortages on Timeliness of Pneumococcal Conjugate Vaccination: Results From the 2001–2005 National Immunization Survey

Abstract

BACKGROUND. In September 2001 and again in February 2004, the Centers for Disease Control and Prevention announced shortages in the supply of the pneumococcal conjugate vaccine. We describe the effects of the pneumococcal conjugate vaccine shortages in 2001–2003 and 2004 on the timeliness of vaccination uptake for quarterly birth cohorts affected by the shortages. METHODS. A total of 102478 19- to 35-month-old children were sampled by the National Immunization Survey between 2001 and 2005. Provider-reported vaccination histories were used to evaluate whether children had been administered ≥4 doses of pneumococcal conjugate vaccine by 16 months of age. RESULTS. Among successive birth cohorts affected by the first shortage, estimated coverage of ≥4 doses of pneumococcal conjugate vaccine by 16 months declined significantly from 28.8% to 18.2%. As the first shortage ended, estimated coverage of ≥4 doses of pneumococcal conjugate vaccine by 16 months increased steadily with each successive birth cohort to 40.2%. From the onset of the second shortage, estimated coverage of ≥4 doses of pneumococcal conjugate vaccine by 16 months declined steadily and significantly to 13.7%. As many as 27% of parents whose child was affected by the first shortage reported that their child's vaccination provider had delayed the administration of pneumococcal conjugate vaccine doses. Of those parents who said that a pneumococcal conjugate vaccine dose was delayed and whose child was not administered ≥4 doses, 2.9% received a reminder notice from the provider to schedule administration of those delayed doses, and 0.2% had an appointment to receive those delayed or missed doses. CONCLUSIONS. Vaccine shortages can result in delayed or missed doses and can have a dramatic impact on the vaccine coverage of children. Vaccination providers need to communicate effectively with parents so that doses that are delayed or missed during a vaccine shortage are administered when the shortage is resolved.