Pneumococcal vaccine cuts hospitalizations

In the 10 years following the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), hospitalizations for pneumococcal disease have been and remain drastically reduced, not just for children but also for adults and particularly for the elderly, according to a new report.

Using a nationwide inpatient sample database, researchers from Vanderbilt University and the Centers for Disease Control and Prevention (CDC) looked at rates of pneumonia-related hospitalizations during the periods 1997 to 1999, before the introduction of the vaccine, and 2007 to 2009, well after the introduction of PCV7 in 2000, but before the switch to 13-valent pneumococcal conjugate vaccine (PCV13) in 2010.

Overall, in all age groups, the investigators calculated a 10.5% reduction in hospitalizations for pneumonia.

Specifically, they calculated a 43.2% decline in annual hospitalizations for pneumonia among children aged younger than 2 years, translating to 47,000 fewer hospitalizations per year than was expected based on the rates before PCV7’s introduction. Notably, the decline in hospitalizations for pneumonia among children was not accompanied by an increase in outpatient visits for pneumonia. Furthermore, the investigators noted that the decline in hospital length of stay and the stability of in-hospital rates of death from pneumonia suggest no major increases in the thresholds for hospital admission.

What is perhaps more surprising than the reduced rate of pneumonia hospitalizations among those who were targeted for vaccination is the reduction in hospitalizations among those not vaccinated. Older adults accounted for more than half the decline in overall hospitalizations for pneumonia. The rate of reduction in adults aged 85 years or older was 22.8%, translating to 73,000 fewer hospitalizations annually.

Also of interest is the fact that as hospitalizations from vaccine serotype disease declined, no real increase occurred in hospitalizations due to nonvaccine serotype disease, which was an early and serious concern. 

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