摘要
Context: Streptococcus pneumoniae is a serious infection in young infants. A heptavalent pneumococcal conjugate vaccine (PCV7) was licensed in 2000 and recommended for all children aged 2 to 23 months. Objective: To determine the rates of invasive pneumococcal disease (IPD) in young infants before and after PCV7 was incorporated into the childhood immunization schedule in June 2000. Design, Setting, and Participants: A prospective, population- based study of infants aged 0 to 90 days who resided in areas in 8 US states with active laboratory surveillance for invasive S pneumoniae infections from July 1, 1997, to June 30, 2004. Main Outcome Measures: Rates of laboratory- confirmed IPD before ( July 1, 1997- June 30, 2000) and after ( July 1, 2001- June 30, 2004)- PCV7 introduction, excluding a transition year ( July 1, 2000- June 30, 2001). Results: There were 146 cases of IPD, 89 before and 57 after PCV7 introduction. Isolated bacteremia occurred in 94 cases (64% ), pneumonia in 27 (18% ), meningitis in 22 (15% )- , and septic arthritis and/or osteomyelitis in 3 (2% ). Mean rates of IPD for infants aged 0 to 90 days decreased 40% from 11.8 (95% confidence interval [CI], 9.6- 14.5) to 7.2 (95% CI, 5.6- 9.4; P=0.004) per 100 000 live births following PCV7 introduction. Among black infants, mean rates of IPD decreased significantly from 17.1 (95% CI, 11.9- 24.6) to 5.3 (95% CI, 2.8- 10.1; P=.001) per 100 000 live births, with a nonsignificant decrease from 9.6 (95% CI, 7.3- 12.7) to 6.8 (95% CI, 4.9- 9.4) per 100 000 live births for white infants. Rates of PCV7- serotype isolates decreased significantly from 7.3 (95% CI, 5.3- 10.1) to 2.4 (95% CI, 1.6- 3.8; P < .001) per 100 000 live births, while rates of non- PCV7 serotypes remained stable (P=.55)- . Conclusions: Since PCV7 introduction, rates of IPD in young infants have decreased significantly, providing evidence that vaccinating children aged 2 to 23 months has led to changes in pneumococcal carriage in infants too young to receive PCV7. With a significant decrease in rates of IPD among black infants, the previous racial difference has been eliminated.
Context: Streptococcus pneumoniae is a serious infection in young infants. A heptavalent pneumococcal conjugate vaccine (PCV7) was licensed in 2000 and recommended for all children aged 2 to 23 months. Objective: To determine the rates of invasive pneumococcal disease (IPD) in young infants before and after PCV7 was incorporated into the childhood immunization schedule in June 2000. Design, Setting, and Participants: A prospective, population- based study of infants aged 0 to 90 days who resided in areas in 8 US states with active laboratory surveillance for invasive S pneumoniae infections from July 1, 1997, to June 30, 2004. Main Outcome Measures: Rates of laboratory- confirmed IPD before ( July 1, 1997- June 30, 2000) and after ( July 1, 2001- June 30, 2004)- PCV7 introduction, excluding a transition year ( July 1, 2000- June 30, 2001). Results: There were 146 cases of IPD, 89 before and 57 after PCV7 introduction. Isolated bacteremia occurred in 94 cases (64% ), pneumonia in 27 (18% ), meningitis in 22 (15% )- , and septic arthritis and/or osteomyelitis in 3 (2% ). Mean rates of IPD for infants aged 0 to 90 days decreased 40% from 11.8 (95% confidence interval [CI], 9.6- 14.5) to 7.2 (95% CI, 5.6- 9.4; P=0.004) per 100 000 live births following PCV7 introduction. Among black infants, mean rates of IPD decreased significantly from 17.1 (95% CI, 11.9- 24.6) to 5.3 (95% CI, 2.8- 10.1; P=.001) per 100 000 live births, with a nonsignificant decrease from 9.6 (95% CI, 7.3- 12.7) to 6.8 (95% CI, 4.9- 9.4) per 100 000 live births for white infants. Rates of PCV7- serotype isolates decreased significantly from 7.3 (95% CI, 5.3- 10.1) to 2.4 (95% CI, 1.6- 3.8; P < .001) per 100 000 live births, while rates of non- PCV7 serotypes remained stable (P=.55)- . Conclusions: Since PCV7 introduction, rates of IPD in young infants have decreased significantly, providing evidence that vaccinating children aged 2 to 23 months has led to changes in pneumococcal carriage in infants too young to receive PCV7. With a significant decrease in rates of IPD among black infants, the previous racial difference has been eliminated.
