摘要：We examined the impact of the heptavalent pneumococcal conjugate vaccine (PCV7) on hospital discharge rates for invasive pneumococcal disease among Michigan children younger than 5 years old. After the introduction of PCV7, the hospital discharge rate for children younger than 1 years old was significantly lower than before introduction. We correlated the decreased rates with the introduction and rapid uptake of PCV7. Lack of change in the hospital discharge rates for other age groups likely represents a slower uptake of PCV7 compared with that for children aged younger than 1 year. Before the heptavalent pneumococcal conjugate vaccine (PCV7) was introduced, Streptococcus pneumoniae (pneumococcus) caused approximately 17 000 cases of invasive disease annually among US children aged younger than 5 years. 1 PCV7 was licensed in February 2000 and is recommended for universal use among children aged 2 to 23 months. 1, 2 Of the more than 90 serotypes of pneumococcus, PCV7 protects against the 7 most common serotypes that comprise 80% of all invasive pneumococcal diseases among children aged younger than 6 years. 1, 3 PCV7 decreased invasive infections by more than 93% during efficacy trials. 4, 5 A previous study that examined data from the Active Bacterial Core Surveillance showed a decrease in the invasive disease rate among children aged 2 years and younger. 6 Our ecological study analyzed whether Michigan’s hospital discharge rates for invasive pneumococcal disease decreased among children younger than 5 years after the introduction of PCV7.
