Risk factors for invasive pneumococcal disease in children in the era of conjugate vaccine use.
OBJECTIVE
We conducted a case-control study to evaluate risk factors for invasive pneumococcal disease (IPD) among children who were aged 3 to 59 months in the era of pneumococcal conjugate vaccine (PCV7).


METHODS
IPD cases were identified through routine surveillance during 2001-2004. We matched a median of 3 control subjects to each case patient by age and zip code. We calculated odds ratios for potential risk factors for vaccine-type and non-vaccine-type IPD by using multivariable conditional logistic regression.


RESULTS
We enrolled 782 case patients (45% vaccine-type IPD) and 2512 matched control subjects. Among children who received any PCV7, children were at increased risk for vaccine-type IPD when they had underlying illnesses, were male, or had no health care coverage. Vaccination with PCV7 did not influence the risk for non-vaccine-type IPD. Presence of underlying illnesses increased the risk for non-vaccine-type IPD, particularly among children who were not exposed to household smoking. Non-vaccine-type case patients were more likely than control subjects to attend group child care, be male, live in low-income households, or have asthma; case patients were less likely than control subjects to live in households with other children.


CONCLUSIONS
Vaccination with PCV7 has reduced the risk for vaccine-type IPD that is associated with race and group child care attendance. Because these factors are still associated with non-vaccine-type IPD risk, additional reductions in disparities should be expected with new, higher valency conjugate vaccines.
Pilishvili
Tamar
T
Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. tpilishvili@cdc.gov
Zell
Elizabeth R
ER
Farley
Monica M
MM
Schaffner
William
W
Lynfield
Ruth
R
Nyquist
Ann-Christine
AC
Vazquez
Marietta
M
Bennett
Nancy M
NM
Reingold
Arthur
A
Thomas
Ann
A
Jackson
Delois
D
Schuchat
Anne
A
Whitney
Cynthia G
CG
D017677:Age Distribution; D016470:Bacteremia / Q000453:epidemiology* / Q000517:prevention & control*; D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D017589:Immunization Programs / Q000458:organization & administration; D015994:Incidence; D007223:Infant; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D020380:Needs Assessment; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control*; D012016:Reference Values; D012307:Risk Factors; D017678:Sex Distribution; D012959:Socioeconomic Factors; D013296:Streptococcus pneumoniae / Q000276:immunology* / Q000302:isolation & purification; D014481:United States / Q000453:epidemiology; D018074:Vaccines, Conjugate / Q000008:administration & dosage
D018074:Vaccines, Conjugate