JAMA
Vol. 302 No. 2, pp. 121-216, July 8, 2009
http://jama.ama-assn.org/current.dtl

Original Contribution
Effect of Reduced-Dose Schedules With 7-Valent Pneumococcal Conjugate Vaccine on Nasopharyngeal Pneumococcal Carriage in Children
A Randomized Controlled Trial

Elske J. M. van Gils, MD; Reinier H. Veenhoven, MD, PhD; Eelko Hak, PhD; Gerwin D. Rodenburg, MD; Debby Bogaert, MD, PhD; Ed P. F. IJzerman, MD, PhD; Jacob P. Bruin; Loek van Alphen, PhD; Elisabeth A. M. Sanders, MD, PhD

JAMA. 2009;302(2):159-167.

Context  The effects of reduced-dose schedules of 7-valent pneumococcal conjugate vaccine (PCV-7) on pneumococcal carriage in children are largely unknown, although highly relevant in the context of subsequent herd effects.

Objective  To examine the effects of a 2-dose and 2 + 1-dose PCV-7 schedule on nasopharyngeal pneumococcal carriage in young children compared with controls.

Design, Setting, and Patients  A randomized controlled trial of nasopharyngeal carriage of Streptococcus pneumoniae enrolling 1003 healthy newborns and 1 of their parents in a general community in the Netherlands, with follow-up to age 24 months and conducted between July 7, 2005, and February 14, 2008.

Intervention  Infants were randomly assigned to receive 2 doses of PCV-7 at 2 and 4 months; 2 + 1 doses of PCV-7 at 2, 4, and 11 months; or no dosage (control group).

Main Outcome Measure  Vaccine serotype pneumococcal carriage rates in infants in the second year of life.

Results  At 12 months, vaccine serotype pneumococcal carriage was significantly decreased after both PCV-7 schedules, with vaccine serotype pneumococcal carriage rates of 25% (95% confidence interval [CI], 20%-30%) and 20% (95% CI, 16%-25%) in the 2-dose and 2 + 1-dose schedule groups, respectively, vs 38% (95% CI, 33%-44%) in the control group (both P < .001). At 18 months, in the 2 + 1-dose schedule group, vaccine serotype pneumococcal carriage had further decreased to 16% (95% CI, 12%-20%) and, at 24 months, to 14% (95% CI, 11%-18%; both P < .001); whereas in the 2-dose schedule group, vaccine serotype pneumococcal carriage had remained stable at 18 months (24%; 95% CI, 20%-29%), but at 24 months had further decreased to 15% (95% CI, 11%-19%; both P < .001). In the control group, vaccine serotype pneumococcal carriage remained around 36% to 38% until 24 months.

Conclusion  Compared with no pneumococcal vaccination, a 2 + 1-dose and 2-dose schedule of PCV-7 resulted in significant reductions of vaccine serotype pneumococcal carriage in the second year of life.

Trial Registration  clinicaltrials.gov Identifier: NCT00189020

Author Affiliations: Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children’s Hospital (Drs van Gils, Hak, Rodenburg, Bogaert, and Sanders), and Julius Center for Health Sciences and Primary Care (Dr Hak), University Medical Center Utrecht, Utrecht; Department of Pediatrics, Spaarne Hospital, Hoofddorp (Drs van Gils, Veenhoven, and Rodenburg); Department of Epidemiology, University Medical Center Groningen, Groningen (Dr Hak); Regional Laboratory of Public Health, Haarlem (Dr IJzerman and Mr Bruin); and Netherlands Vaccine Institute, Bilthoven (Dr van Alphen), the Netherlands.