Impact of a conjugate vaccine on community-wide carriage of nonsusceptible Streptococcus pneumoniae in Alaska.
BACKGROUND
Streptococcus pneumoniae is a leading cause of invasive bacterial disease and pneumonia among children. Antimicrobial resistance among pneumococci has increased in recent years and complicates treatment. The introduction of heptavalent pneumococcal conjugate vaccine (PCV7) could reduce acquisition of antimicrobial-resistant pneumococci.


METHODS
We obtained 1350 nasopharyngeal swabs for culture from 1275 children aged 3-59 months presenting at 3 clinics in Anchorage, Alaska, during the winters of 2000, 2001, and 2002, as PCV7 was being introduced into the routine immunization schedule. We recorded the frequency of use of antibiotics as well as the dates of doses of PCV7 for enrolled children. We used multivariate logistic regression modeling to identify independent risk factors for overall carriage of pneumococci and carriage of PCV7-type pneumococci, cotrimoxazole-nonsusceptible (COT-NS) pneumococci, or penicillin-nonsusceptible (PCN-NS) pneumococci.


RESULTS
The proportion of children who were up-to-date for age, with respect to PCV7 vaccination, increased from 0% in 2000 to 55% in 2002. Carriage of PCV7-type pneumococci decreased by 43% (P<.0001). Risk of carriage of PCV7-type pneumococci was lower in 2002 than in 2000, independent of vaccination status, suggesting an indirect effect of vaccination. Carriage of COT-NS, but not PCN-NS, pneumococci also decreased (38%; P=.02), not only among vaccinated children but also among unvaccinated children without recent use of antibiotics.


CONCLUSIONS
Introduction of PCV7 into the routine infant immunization schedule in a community with a high prevalence of antimicrobial-resistant pneumococci appears to reduce transmission of PCV7 vaccine serotypes and COT-NS pneumococci but has no impact on overall carriage of pneumococci or carriage of PCN-NS pneumococci.
Moore
Matthew R
MR
Division of Applied Public Health Training, Epidemiology Program Office, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333, USA. mmoore4@cdc.gov
Hyde
Terri B
TB
Hennessy
Thomas W
TW
Parks
Debra J
DJ
Reasonover
Alisa L
AL
Harker-Jones
Marcella
M
Gove
James
J
Bruden
Dana L
DL
Rudolph
Karen
K
Parkinson
Alan
A
Butler
Jay C
JC
Schuchat
Anne
A
D000413:Alaska; D000890:Anti-Infective Agents / Q000494:pharmacology; D002353:Carrier State / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage*; D009305:Nasopharynx / Q000382:microbiology; D010044:Outpatient Clinics, Hospital; D010406:Penicillins / Q000494:pharmacology; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012307:Risk Factors; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics; D013997:Time Factors; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014505:Urban Population; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000008:administration & dosage
D000890:Anti-Infective Agents; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D010406:Penicillins; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate; D015662:Trimethoprim, Sulfamethoxazole Drug Combination