Invasive Pneumococcal Disease Among Infants Before and After Introduction of Pneumococcal Conjugate Vaccine
- Katherine A. Poehling, MD, MPH;
- Thomas R. Talbot, MD, MPH;
- Marie R. Griffin, MD, MPH;
- Allen S. Craig, MD;
- Cynthia G. Whitney, MD, MPH;
- Elizabeth Zell, MStat;
- Catherine A. Lexau, PhD, MPH;
- Ann R. Thomas, MD, MPH;
- Lee H. Harrison, MD;
- Arthur L. Reingold, MD;
- James L. Hadler, MD, MPH;
- Monica M. Farley, MD;
- Bridget J. Anderson, PhD;
- William Schaffner, MD
- Author Affiliations: Departments of Pediatrics (Dr Poehling), Medicine (Drs Talbot, Griffin, and Schaffner), Preventive Medicine (Drs Talbot, Griffin, and Schaffner), and Center for Education and Research on Therapeutics (Dr Griffin), Vanderbilt University School of Medicine and the Tennessee Department of Health (Dr Craig), Nashville; National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Ga (Dr Whitney and Ms Zell); Infectious Disease Epidemiology, Minnesota Department of Health, Minneapolis (Dr Lexau); Office of Disease Prevention and Epidemiology, Oregon Department of Human Services, Portland (Dr Thomas); Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Md, and Graduate School of Public Health and School of Medicine, University of Pittsburgh, Pittsburgh, Pa (Dr Harrison); School of Public Health, University of California, Berkeley (Dr Reingold); Infectious Diseases Section, Connecticut Department of Health, Hartford (Dr Hadler); Emory University School of Medicine and the Atlanta Veteran Affairs Medical Center, Atlanta, Ga (Dr Farley); and Emerging Infections Program, New York State Department of Health, Albany (Dr Anderson).
- Corresponding Author: Katherine A. Poehling, MD, MPH, Department of Pediatrics, Vanderbilt University School of Medicine, AA-0216 Medical Center N, Nashville, TN 37232-2504 (katherine.poehling{at}vanderbilt.edu).
Abstract
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 = .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.
