Nasopharyngeal pneumococcal carriage after combined pneumococcal conjugate and polysaccharide vaccination in children with a history of recurrent acute otitis media.
BACKGROUND
We recently showed that vaccination with a 7-valent pneumococcal conjugate vaccine (PCV7) followed by a 23-valent pneumococcal polysaccharide vaccine (PPSV23) failed to prevent new episodes of acute otitis media (AOM) in previously unvaccinated toddlers and children with a history of recurrent AOM. We describe in detail the impact of pneumococcal vaccinations on nasopharyngeal carriage of S. pneumoniae in this study population.


METHODS
The impact of vaccination with PCV7 followed by PPSV23 on pneumococcal nasopharyngeal carriage was studied in a prospective, randomized trial involving 383 children (age range, 1-7 years) with previous AOM. Nasopharyngeal swab specimens were collected at the time of first vaccination and at 6-7-month intervals during the 26-month follow-up period.


RESULTS
Overall, pneumococcal carriage rates did not diminish, remaining at approximately 50% in both PCV7/PPSV23 and control vaccinees. A significant shift from conjugate vaccine- to nonconjugate vaccine-type pneumococci was observed in children aged 1-2 years, who received the conjugate vaccine twice before the polysaccharide vaccine was administered. Conjugate vaccine serotype carriage was not influenced in older children, who received the conjugate vaccine once before receiving the polysaccharide booster.


CONCLUSIONS
The administration of conjugate vaccines at least twice also after 2 years of age may be mandatory for reducing the carriage of conjugate vaccine serotypes in children with recurrent AOM. Polysaccharide booster vaccination did not affect nasopharyngeal colonization with serotypes not included in the conjugate vaccine.
Department of Pediatrics, Spaarne Hospital, Haarlem, The Netherlands.
Reinier H
RH
Veenhoven
Debby
D
Bogaert
Anne G M
AG
Schilder
Ger T
GT
Rijkers
Cuno S P M
CS
Uiterwaal
Herma H
HH
Kiezebrink
Muriel J P
MJ
van Kempen
Inge J
IJ
Dhooge
Jacob
J
Bruin
Ed P F
EP
Ijzerman
Ronald
R
de Groot
Wietse
W
Kuis
Peter W M
PW
Hermans
Elisabeth A M
EA
Sanders
D000375:Aging; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology*; D010033:Otitis Media / Q000150:complications*; D022242:Pneumococcal Vaccines / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*; D018074:Vaccines, Conjugate / Q000276:immunology
D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate