Chapter 128. Pneumococcal Infections (Part 10)

PreventionCapsular Polysaccharide VaccineThe pneumococcal capsular polysaccharide vaccine administered to adults since the early 1980s contains 25 µg per dose of capsular polysaccharide from each of the 23 most prevalent serotypes of S. pneumoniae. Vaccination stimulates antibody to most serotypes in most recipients. One case-control study showed a protection rate of 85% lasting ≥5 years in adults
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Chapter 128. Pneumococcal Infections (Part 10) Chapter 128. Pneumococcal Infections (Part 10) Prevention Capsular Polysaccharide Vaccine The pneumococcal capsular polysaccharide vaccine administered to adultssince the early 1980s contains 25 µg per dose of capsular polysaccharide fromeach of the 23 most prevalent serotypes of S. pneumoniae. Vaccination stimulatesantibody to most serotypes in most recipients. One case-control study showed aprotection rate of 85% lasting ≥5 years in adults Control and Prevention has broadened its recommendations for pneumococcalvaccination to include all persons >2 years of age who are at substantiallyincreased risk of developing pneumococcal infection and/or having a seriouscomplication of such an infection. Perhaps most in need of vaccination are personswith anatomic or functional asplenia, who are at risk for overwhelming, life-threatening infections. Others who might fall within these recommendations arepersons who (1) are over the age of 65; (2) have a CSF leak, diabetes mellitus,alcoholism, cirrhosis, chronic renal insufficiency, chronic pulmonary disease, oradvanced cardiovascular disease; (3) have an immunocompromising conditionassociated with increased risk of pneumococcal disease (e.g., multiple myeloma,lymphoma, Hodgkins disease, HIV infection, organ transplantation, or chronicglucocorticoid use); (4) are genetically at increased risk (e.g., Native Americansand Native Alaskans); or (5) live in environments where outbreaks are particularlylikely to occur (e.g., nursing homes). Table 128-7 Protective Efficacy of Polyvalent PneumococcalPolysaccharide Vaccinea Years since Last Vaccination Age, No. of Subject 5Years Pairs infection, and this decline is more prominent in older patients. Source: Data adapted from ED Shapiro et al: N Engl J Med 325:1453,1991; with permission. Recommendations regarding revaccination seem somewhat inconsistent. Asingle revaccination is advocated for persons over the age of 65 if >5 years haveelapsed since the first vaccination. Since antibody levels decline and there is noanamnestic response, it seems more reasonable simply to recommendrevaccination at 5-year intervals, especially in persons over the age of 65, whotend to have almost no adverse reaction to vaccination, and in splenectomizedpatients, who are most in need. Protein-Conjugate Pneumococcal Vaccine Pneumococcal polysaccharide vaccine is not useful in children caused a dramatic decline in the incidence of invasive pneumococcal diseaseamong infants and children (Fig. 128-4). Colonization rates have also greatlydecreased. In an Alaskan village, rates of carriage of vaccine strains decreased inchildren from 55% to 10% and in adults from 15% to 5%. Studies of proteinconjugate vaccines that contain antigen from more than seven common infectingserotypes are nearing completion, with favorable results. Figure 128-4 The rate of invasive pneumococcal disease per 100,000 population(vertical axis) is presented for each year since 2000 (bars) for different age groups(horizontal axis). Invasive pneumococcal disease is more common at the extremesof age. The incidence in all age groups has fallen steadily during the past 5 years.The observed reductions reflect direct effects and indirect (herd) effects ofwidespread use of the 7-valent pneumococcal protein-conjugate vaccine (PCV7;see text). (Adapted from Centers for Disease Control and Prevention, MMWR54:893, 2005.) The incidence of invasive pneumococcal disease has also declined amongunvaccinated children and among adults, to whom this vaccine is not even offered(Fig. 128-4). This decrease illustrates the herd effect—i.e., the impact ofwidespread vaccination on unvaccinated members of the population—and isprobably attributable to the effects of the conjugate vaccine on nasopharyngealcarriage of vaccine serotypes. Another effect of the widespread use of this vaccineis the decreasing proportion of all pneumococcal disease that is due to antibiotic-resistant isolates, a trend that reflects the targeting of antibiotic-resistant strains bythe vaccine. An unwanted effect of vaccination has been an increase in infectionscaused by serotypes that are not included in the vaccine (replacement serotypes),which, in fact, are increasingly expressing antibiotic resistance. Still, as notedabove, the overall incidence of pneumococcal disease in all segments of thepopulation has steadily declined. For further information, the reader is referred tothe American Academy ...