Pneumococcal Disease Mortality in the United States, 1990-2004

Learning Objectives for this Presentation:
By the end of the presentation the participants will be able to describe the burden of pneumococcal-related mortality in the United States.

Background:
Streptococcus pneumoniae causes significant mortality in the U.S. Approximately 40,000 deaths occur each year in the U.S. as a result of pneumococcal infection. Following the widespread use of PCV7, childhood mortality has decreased. Adult mortality rates have decreased, but not proportional to the decrease in adult pneumococcal disease incidence. A study dedicated to examining pneumococcal-related mortality in the U.S. is needed to understand the extent of the burden S. pneumoniae places on society.

Objectives:
To assess the burden of pneumococcal disease mortality in persons living in the U.S. and examine demographic differences and seasonal and secular trends in pneumococcal disease mortality in the pre-PCV7 and post-PCV7 eras.

Methods:
Cases were any mention of pneumococcal disease, selected from Multiple-Cause-of-Death (death certificate) data files, 1990-2004. Linear regressions assessed age and temporal trends. Chi-square tests assessed seasonal differences in pneumococcal-related deaths. Age-adjusted rates (standard year:2000) were also calculated.

Results:
There was a statistically significant decline in age-adjusted mortality rates in both the pre- and post-vaccine eras. Age was a statistically significant predictor of pneumococcal-related mortality rates. In persons aged 20-99 years, linear regression shows a 50% average increase in mortality rate for each 10-year interval post-PCV7, compared to over 300% average increase pre-vaccine. Following disease trends, mortality is significantly higher in the winter months. The mortality rate ratios (reference:Caucasians) improved for most ethnicities in the post-vaccine era, except for Native Americans(pre-vaccine:1.72; post-vaccine:2.82). Although the rate ratio for Asian/Pacific Islanders(API) improved overall, API children under 5 years did far worse (pre-vaccine:0.75; post-vaccine:1.41).

Conclusions:
Pneumococcal-related mortality has decreased over the past 15 years. Although PCV7 is administered to children, it seems to also benefit older persons. However, not all ethnic groups have been affected equally by PCV7.