Effect of reduced-dose schedules with 7-valent pneumococcal conjugate vaccine on nasopharyngeal pneumococcal carriage in children: a randomized controlled trial.
BACKGROUND
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.


METHODS
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.


METHODS
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).


METHODS
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.


CONCLUSIONS
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.


BACKGROUND
clinicaltrials.gov Identifier: NCT00189020.
van Gils
Elske J M
EJ
Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, PO Box 85090, 3508 AB Utrecht, The Netherlands.
Veenhoven
Reinier H
RH
Hak
Eelko
E
Rodenburg
Gerwin D
GD
Bogaert
Debby
D
Ijzerman
Ed P F
EP
Bruin
Jacob P
JP
van Alphen
Loek
L
Sanders
Elisabeth A M
EA
D002353:Carrier State / Q000517:prevention & control*; D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D007231:Infant, Newborn; D009305:Nasopharynx / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification*; D018074:Vaccines, Conjugate
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate