Effectiveness of 23-valent pneumococcal polysaccharide vaccination in preventing community-acquired pneumonia hospitalization and severe outcomes in the elderly in Spain

Abstract

Pneumococcal pneumonia is a serious cause of morbidity and mortality in the elderly, but investigation of the etiological agent of community-acquired pneumonia (CAP) is not possible in most hospitalized patients. The aim of this study was to estimate the effect of pneumococcal polysaccharide vaccination (PPSV23) in preventing CAP hospitalization and reducing the risk of intensive care unit admission (ICU) and fatal outcomes in hospitalized people aged ≥65 years. We made a multicenter case-control study in 20 Spanish hospitals during 2013–2014 and 2014–2015. We selected patients aged ≥65 years hospitalized with a diagnosis of pneumonia and controls matched by sex, age and date of hospitalization. Multivariate analysis was performed using conditional logistic regression to estimate vaccine effectiveness and unconditional logistic regression to evaluate the reduction in the risk of severe and fatal outcomes. 1895 cases and 1895 controls were included; 13.7% of cases and 14.4% of controls had received PPSV23 in the last five years. The effectiveness of PPSV23 in preventing CAP hospitalization was 15.2% (95% CI -3.1–30.3). The benefit of PPSV23 in avoiding ICU admission or death was 28.1% (95% CI -14.3–56.9) in all patients, 30.9% (95% CI -32.2–67.4) in immunocompetent patients and 26.9% (95% CI -38.6–64.8) in immunocompromised patients. In conclusion, PPSV23 showed a modest trend to avoidance of hospitalizations due to CAP and to the prevention of death or ICU admission in elderly patients hospitalized with a diagnosis of CAP.

A Systematic Review of Studies Published between 2016 and 2019 on the Effectiveness and Efficacy of Pneumococcal Vaccination on Pneumonia and Invasive Pneumococcal Disease in an Elderly Population

“…For PPV23 we identified one cohort study from Germany [20], one TND study from Japan [21], one indirect cohort study from United Kingdom (UK) [22] and three case-control studies from Spain [23], Japan [24] and South Korea [25], respectively ( Table 1). The German cohort study included almost 739,000 inhabitants aged ≥60 years, retrospectively, using routine insurance data collected between 2010 and 2011.…”

“…Among these, 6245 (63%) had available vaccination information, and were included in VE analysis using the indirect cohort (Broome) method, with 4423 VT IPD cases and 1822 non VT-IPD controls [22]. The case-control study from Spain recruited 1895 CAP cases and an equal amount of controls from 20 different hospitals between 2013 and 2015 [23]. The Japanese case-control study matched 234 outpatients treated for pneumonia between 2009 and 2014 with 438 controls without pneumonia [24].…”

“…VE of the PPV23 vaccine was reported on the following outcomes: all-cause pneumonia [20], CAP [23,24], non-bacteremic pneumococcal pneumonia (NBPP) [25], VT-NBPP [25], pneumococcal pneumonia [21] and VT-pneumonia [21], IPD [25] and VT-IPD [22,25] (Table 1).…”

“…We judged the Italian TND study on PCV13 [19], the German cohort on PPV23 [20], the Spanish case-control on PPV23 [23] and the Japanese case-control study on PPV23 [24] to be of low quality according to NOS criteria (Table 1 + Table S2). The Italian study had a low inclusion rate of only 10%, stopped before planned time, and did not adjust for confounding factors [19].…”

“…The Spanish case-control used medical records to judge vaccination status. The included cases and controls had a lower vaccination coverage than average in this region and 90% had one or more comorbidity; this suggests some selection and information bias [23]. In the Japanese case-control study vaccination status and comorbidities were based on self-reporting, introducing a risk of recall bias.…”