One influenza vaccination RCT (125 patients) and one pneumococcal vaccination RCT (596 patients) were included in the review. Patients who received pneumococcal vaccination were followed up to three years. Quality was considered high for the influenza vaccination RCT for episodes of influenza-related acute respiratory illness and high for the pneumococcal vaccination for the first episode of community acquired pneumonia. Quality was considered low for all other outcomes.
Influenza: The overall effectiveness of the vaccination against flu virus was 76% compared to placebo (RR 0.24, 95% CI 0.09 to 0.67). Effectiveness rates by severity of chronic obstructive pulmonary disease were 84% (mild), 45% (moderate) and 85% (severe). Outcome data were not statistically significant between treatment and placebo groups for hospitalisation or mechanical ventilation.
Statistically significantly more patients who received vaccine compared to placebo experienced local adverse reactions (p=0.002), swelling (p=0.04) and itching (p=0.04).
Pneumonia: There was no statistically significant difference in the overall effectiveness between vaccination and control groups in the rate of pneumonia (RR 0.76, 95% CI 0.46 to 1.24). There were statistically significant reductions in incidence of pneumonia of unknown aetiology and pneumococcal pneumonia for some subgroups (as reported in the review). There were no statistically significant differences in hospitalisation or mortality rates. None of the patients reported local or systemic reactions to the vaccine.
Other results were reported in the review.