Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Invasive Disease and Hospital-Treated Pneumonia Among People Aged ≥65 Years: A Retrospective Case-Control Study

Clinical Infectious Diseases, Apr 2015

Background. Streptococcus pneumoniae contributes considerably to the burden of pneumonia and invasive pneumococcal disease (IPD), with the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) for preventing all-cause pneumonia still undetermined. The aim of this study was to control for common biases and confounders associated with previous observational studies and to assess PPSV23 vaccine effectiveness in preventing IPD and the most resource-intensive type of community-acquired pneumonia, hospital-treated pneumonia (HTP). Methods. This was a retrospective case-control study nested in a population-based cohort, with age-, sex-, and risk-matched controls as the base case. Demographic information, laboratory data, and diagnoses were extracted from the chronic disease registry and from inpatient and outpatient records in the Clalit Health Services database. Vaccine effectiveness for PPSV23 was assessed using multivariable conditional logistic regression. Subgroup, sensitivity, and secondary analyses were conducted to validate findings. Results. A total of 470 070 individuals aged ≥65 years were members of Clalit Health Services during the study period (1 January 2007 through 31 December 2010). The case cohort consisted of 212 participants with IPD and 23 441 with HTP. The adjusted association between vaccination and IPD was protective (odds ratio [OR], 0.58; 95% confidence interval [CI], .41–.81), whereas there was no demonstrated protective effect between vaccination and HTP (OR, 1.01; 95% CI, .97–1.04). The sensitivity analysis and all but 1 subgroup analysis provided consistent results to the base case. Conclusions. The PPSV23 vaccine is effective against the most severe invasive forms of pneumococcal disease, but the lack of effectiveness of PPSV23 in protecting against all-cause HTP should be considered for future vaccine policies.

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Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Invasive Disease and Hospital-Treated Pneumonia Among People Aged ≥65 Years: A Retrospective Case-Control Study

CID Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Invasive Disease and Hospital-Treated Pneumonia Among People Aged ≥65 Years: A Retrospective Case-Control Study Maya Leventer-Roberts 1 Becca S. Feldman Ilan Brufman Chandra J. Cohen-Stavi Moshe Hoshen Ran D. Balicer 0 0 Department of Epidemiology, Faculty of Health Sciences, Ben Gurion University , Be'er Sheva , Israel 1 Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai , New York , New York Background. Streptococcus pneumoniae contributes considerably to the burden of pneumonia and invasive pneumococcal disease (IPD), with the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) for preventing all-cause pneumonia still undetermined. The aim of this study was to control for common biases and confounders associated with previous observational studies and to assess PPSV23 vaccine effectiveness in preventing IPD and the most resource-intensive type of community-acquired pneumonia, hospital-treated pneumonia (HTP). Methods. This was a retrospective case-control study nested in a population-based cohort, with age-, sex-, and risk-matched controls as the base case. Demographic information, laboratory data, and diagnoses were extracted from the chronic disease registry and from inpatient and outpatient records in the Clalit Health Services database. Vaccine effectiveness for PPSV23 was assessed using multivariable conditional logistic regression. Subgroup, sensitivity, and secondary analyses were conducted to validate findings. Results. A total of 470 070 individuals aged ≥65 years were members of Clalit Health Services during the study period (1 January 2007 through 31 December 2010). The case cohort consisted of 212 participants with IPD and 23 441 with HTP. The adjusted association between vaccination and IPD was protective (odds ratio [OR], 0.58; 95% confidence interval [CI], .41-.81), whereas there was no demonstrated protective effect between vaccination and HTP (OR, 1.01; 95% CI, .97-1.04). The sensitivity analysis and all but 1 subgroup analysis provided consistent results to the base case. Conclusions. The PPSV23 vaccine is effective against the most severe invasive forms of pneumococcal disease, but the lack of effectiveness of PPSV23 in protecting against all-cause HTP should be considered for future vaccine policies. Worldwide, Streptococcus pneumoniae contributes considerably to morbidity and mortality due to bacterial vaccine effectiveness; pneumococcal vaccination; invasive pneumococcal disease; pneumonia - respiratory tract infection and invasive disease [ 1, 2 ]. An estimated 23%–50% of community-acquired pneumonia (CAP) cases are caused by S. pneumoniae [ 3, 4 ]. Severe forms of CAP may require hospitalization and extended hospital stays, which adds to the disease burden [ 5, 6 ]. Those at increased risk for the rarer, but more serious, invasive pneumococcal disease (IPD) include older and immunocompromised adults [ 2, 5, 7 ]. There are 2 types of vaccines administered for preventing pneumococcal infections. The 23-valent pneumococcal polysaccharide vaccine (PPSV23) consists of serotypes corresponding to 85%–90% of IPD isolates [ 8 ], and the 13-valent pneumococcal conjugate vaccine (PCV13) consists of serotypes corresponding to >60% of disease isolates in children [ 9 ]. PPSV23 potentially affords broader protection against IPD because it covers a larger proportion of serotypes found in IPD cases; however, it lacks the superior immunogenicity of the conjugated vaccine [ 10–12 ]. The current recommendations in Israel and other countries are to give PPSV23 to all adults aged ≥65 years and those aged <65 years with certain risk factors, and to administer PCV13 in the pediatric population [ 13 ]. Several randomized controlled trials and meta-analyses have reproduced initial findings that PPSV23 is likely to be effective in preventing IPD among adults [ 14–18 ], and a few studies have suggested that PPSV23 is possibly effective in preventing pneumococcal pneumonia [ 19, 20 ]. Conversely, there have also been multiple reviews and meta-analyses indicating that there is insufficient evidence [ 21–23 ] and significant methodological shortcomings limiting conclusions about PPSV23’s effectiveness against IPD and pneumonia [ 24, 25 ]. Observational studies assessing vaccination effectiveness in general populations demonstrated both effectiveness and a lack thereof [ 4, 8, 26–28 ]. Recently, an observational study by Ochoa-Gondar et al [ 29 ] found that PPSV23 was protective for all-cause pneumonia and pneumococcal pneumonia among a subgroup of patients more recently vaccinated. Given the inconsistent evidence on the effectiveness of PPSV23 and the initial results reporting efficacy of PCV13 against pneumococcal pneumonia in an adult population [ 30 ], the question has been raised whether PPSV23 could be complemented with, or replaced by, PCV13 [ 12 (...truncated)


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Maya Leventer-Roberts, Becca S. Feldman, Ilan Brufman, Chandra J. Cohen-Stavi, Moshe Hoshen, Ran D. Balicer. Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Invasive Disease and Hospital-Treated Pneumonia Among People Aged ≥65 Years: A Retrospective Case-Control Study, Clinical Infectious Diseases, 2015, pp. 1472-1480, 60/10, DOI: 10.1093/cid/civ096