7-Valent pneumococcal conjugate vaccine and otitis media: effectiveness of a 2-dose versus 3-dose primary series.
BACKGROUND
Seven-valent pneumococcal conjugate vaccination (PCV7) has been shown to reduce rates of otitis media (OM) when given as a 2- or 3-dose primary series followed by a booster dose. However, data on the 2- or 3-dose primary series' relative effectiveness against OM is very limited. Using data from the United States after the 2000 introduction of PCV7, we compared the effectiveness of a 2- versus a 3-dose primary series against acute otitis media (AOM).


METHODS
We examined the 2002 birth cohort from the Medstat MarketScan insurance claims database and compared the incidence of AOM in children that received two or three doses in the primary PCV7 series using propensity score matching. We assessed AOM rates after completion of the primary series and before the booster dose, and after the booster dose until four years of age.


RESULTS
Among the 2002 birth cohort captured by MarketScan, we identified 38,786 children we could match with immunization data; of these 8515 (22%) received a 2-dose primary series and 10,152 (26%) received a 3-dose primary series. After matching, cumulative AOM incidence between 6 and 12 months among children who did not receive a PCV7 dose between the primary series and the booster dose was 37.6% for the 2-dose series and 35.0% for the 3-dose series. This difference was not statistically significant (p=0.22). Cumulative AOM incidence between one and four years, i.e., after the booster dose, was 104.4% for the 2-dose primary series and 102.5% for the 3-dose primary series, and the difference between them was also statistically insignificant.


CONCLUSIONS
In a population of highly-insured children, a 2-dose primary series of PCV7 appears to provide similar protection against AOM as a 3-dose primary series. These data have important implications for national immunization programs where AOM is an important driver of cost-effectiveness.
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. cstoecker@cdc.gov
Charles
C
Stoecker
Lee M
LM
Hampton
Matthew R
MR
Moore
D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D007345:Insurance Claim Review; D008297:Male; D010033:Otitis Media / Q000453:epidemiology* / Q000517:prevention & control*; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014611:Vaccination / Q000379:methods*
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines