[Risk of pneumococcal disease in elderly patients with and without previous vaccination].

OBJECTIVES

To know the pneumococcal vaccination coverage in patients≥65 years old, as well as the risk of pneumococcal disease according to whether or not they received such vaccination.

DESIGN

Cross-sectional study, followed by historical cohort.

LOCATION

Urban area.

PARTICIPANTS

By systematic sampling, 2,805 people≥65 years from the city of Albacete were selected.

MAIN MEASUREMENTS

Dependent variable: diagnosis of pneumococcal disease and date.

INDEPENDENT VARIABLES

age, sex, chronic pathologies, medication, pneumococcal vaccination and date. The computerized medical records were reviewed, from 1-1-2009 to October-December 2015. A descriptive analysis was carried out, the relative risk of the onset of pneumococcal disease according to vaccination has been calculated, and survival analysis has been carried out, with the statistical program SPSS 17.0.

RESULTS

Median age 71 years; 57.2% were women; 46% received polysaccharide vaccine (95% CI 44.1-47.8). Only 10 people received conjugated vaccine. Twenty-two people were diagnosed with invasive pneumococcal disease and 153 non-invasive. The relative risk of pneumococcal disease in vaccinated versus unvaccinated, respectively for invasive and non-invasive, was 1.59 (95% CI 0.69-3.68) and 1.84 (95% CI 1.33-2.54). Cox regression showed a higher risk of non-invasive disease for COPD (1.95; 95% CI 1.32-2.89), smoking (1.87; 95% CI 1.28-2.73), corticoid-therapy (1.73; 95% CI 1.08-2.79), polysaccharide vaccination (141.41; 95% CI 5.92-3,378.49) and age (1.11; 95% CI 1.08-1.14), with interaction between these 2 (0.94, 95% CI 0.91-0.98).

CONCLUSIONS

There is an increased risk of pneumococcal disease in patients≥65 years vaccinated with polysaccharide, although with a protective effect in vaccinated older.