Changing disparities in invasive pneumococcal disease by socioeconomic status and race/ ethnicity in Connecticut, 1998-2008.

OBJECTIVES: We compared invasive pneumococcal disease (IPD) incidence by race/ethnicity and neighborhood poverty level and assessed their relative utility to describe disparities in IPD in 1998-1999 and again in 2007-2008, after introduction of the 7-valent pneumococcal conjugate vaccine (PCV7).
METHODS: We conducted laboratory surveillance for pneumococcal isolates from sterile body sites and serotyped the isolates. Home address was geocoded to the census-tract level. Census-tract data on the percentage of people below poverty were grouped into three categories. The difference in the magnitude of incidence by race/ethnicity and by census-tract socioeconomic status (SES) (high poverty minus low poverty) was compared for 1998-1999 and 2007-2008 for PCV7 and non-PCV7 serotypes.
RESULTS: In 1998-1999, incidence difference (all per 100,000 population) for PCV7 serotypes for black people compared with white people was 14.3 and by poverty level was 13.9. The highest rate was among white people in high-poverty tracts (77.3). By 2007-2008, there were only slight differences between rates for black and white people (0.7) and SES (1.4). In 1998-1999, the incidence difference for non-PCV7 serotypes was 4.7 between black and white people and 6.0 by SES. By 2007-2008, the differences were 11.6 and 11.7, respectively. Among those living in the highest-poverty tracts, white people had the highest rate (42.9).
CONCLUSIONS: In the absence of vaccine, IPD incidence is higher among people living in higher-poverty census tracts and among black people. Emerging serotypes also follow this trend. Differences in neighborhood poverty levels reveal disparities in rates of IPD as large as those seen by race/ethnicity and could be used to routinely describe disparities and target prevention.