The pneumococcal conjugate vaccine (PCV-7) was licensed for use in infants and young children in March 2000, according to background information in the article. Use of PCV-7 in children can affect pneumonia transmission in the community. Pneumonia causes substantial illness and death among older adults. Consistent with the ability of PCV-7 to interrupt transmission, declines in invasive pneumococcal disease incidence among older adults were observed in 2001, the year after PCV-7 introduction.
Catherine A. Lexau, Ph.D., M.P.H., of the Minnesota Department of Health, St. Paul, Minn., and colleagues conducted a study to determine whether the observed early decline among adults aged 50 years and older has continued over the 4 years since pneumococcal conjugate vaccine licensure, whether disease characteristics have changed, and whether the spectrum of patients acquiring invasive pneumococcal disease has changed. The study included population-based surveillance data of invasive pneumococcal disease in 8 U.S. geographic areas (total population, 18,813,000), 1998-2003.
The researchers found that the incidence of invasive pneumococcal disease among adults aged 50 years or older declined 28 percent, from 40.8 cases/100,000 in 1998-1999 to 29.4 in 2002-2003. During 2002 and 2003, the overall rate of invasive disease among persons aged 65 years or older (41.7 cases/100,000) was lower than the Healthy People 2010 goal of 42 cases/100,000. Among adults aged 50 years or older, incidence of disease caused by the 7 conjugate vaccine serotypes declined 55 percent from 22.4 to 10.2 cases/100,000.
In contrast, disease caused by any of the 16 serotypes only in polysaccharide vaccine did not change, and disease caused by serotypes not in either vacci
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