Specific pneumococcus serotypes associated with increased mortality
Invasive pneumococcal disease (IPD) remains a major cause of morbidity and mortality worldwide despite the availability of antibiotic therapy and vaccines. Developing countries bear the major burden of IPD along with significantly higher rates of death and disability. The introduction of a 7-valent pneumococcal conjugate vaccine (PCV7) for infants has significantly reduced rates of bacteremic and nonbacteremic pneumococcal disease in the United States and other industrialized countries, yet the emergence of nonvaccine pneumococcal serotypes may threaten the continued efficacy of conjugate vaccines. Unfortunately, since the prevalence of pneumococcal serotypes varies among geographical regions, the formulation of PCV7 is not optimal against the most prevalent serotypes found in the developing world. In addition, some controversy surrounds the use of the available 23-valent polysaccharide vaccine (PPV23), which is recommended for patients of 2 years and older with high-risk conditions and for the elderly, since controlled trials were inconclusive and observational data suggested that PPV23 may prevent bacteremic but not non-bacteremic disease.
In research published this week, doctors analyzed population-based data collected over 30 years in more than 18,000 patients with invasive pneumococcal infection, finding specific pneumococcal serotypes to be associated with increased mortality. The results confirm that age, co-existing conditions and clinical presentation affect the serotype distribution as well as determine outcomes from IPD. This work is the largest and most comprehensive population-based study to date that evaluates short-term mortality associated with invasive pneumococcal serotypes after adjustment for possible confounders. The results support the hypothesis that specific pneumococcal capsular serotypes are significantly and independently associated with short-term mortality in patients with IPD. This is of particular interest in the era of conjugate vaccination, because a limited number of serotypes are included in the vaccines and because of the current emergence of nonvaccine serotypes.
Pneumococcal Serotypes and Mortality following Invasive Pneumococcal Disease: A Population-Based Cohort Study. PLoS Med 6(5): e1000081
Pneumococcal disease is a leading cause of morbidity and mortality worldwide. The aim of this study was to investigate the association between specific pneumococcal serotypes and mortality from invasive pneumococcal disease (IPD). In a nationwide population-based cohort study of IPD in Denmark during 1977–2007, 30-day mortality associated with pneumococcal serotypes was examined by multivariate logistic regression analysis after controlling for potential confounders. A total of 18,858 IPD patients were included. Overall 30-day mortality was 18%, and 3% in children younger than age 5 y. Age, male sex, meningitis, high comorbidity level, alcoholism, and early decade of diagnosis were significantly associated with mortality. Among individuals aged 5 y and older, serotypes 31, 11A, 35F, 17F, 3, 16F, 19F, 15B, and 10A were associated with highly increased mortality as compared with serotype 1. In children younger than 5 y, associations between serotypes and mortality were different than in adults but statistical precision was limited because of low overall childhood-related mortality. Specific pneumococcal serotypes strongly and independently affect IPD associated mortality.
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Tags: Bacteria, Biology, disease, Health, Medicine, Microbiology, pneumococcus, Science, Streptococcus pneumoniae, Vaccines
