Additive preventive effect of influenza and pneumococcal vaccines in the elderly

Abstract

Elderly people are at increased risk of influenza and pneumococcal diseases. Influenza increases clinical pneumococcal disease incidence. Pneumococcal vaccination could therefore be a supplement to influenza vaccination. This study evaluated all-cause mortality and antibiotic consumption according to elderly people’s influenza and pneumococcal vaccination status. Its goal was to demonstrate that vaccination with both Influenza and pneumococcal vaccines decrease all-cause mortality and antibiotic consumption. From 2004-10-01 to 2004-12-31 (3 mo), elderly people (≥ 65 y) who lived in the Gard department (South of France) were offered both vaccinations. Among the 68,897 subjects followed-up one year after this vaccination campaign, 21,303 (30.9%) were vaccinated with both vaccines, 18,651 (27.1%) with influenza vaccine alone, 3,769 (5.5%) with pneumococcal vaccine alone; 25,174 (36.5%) subjects were unvaccinated. Mortality rate (per 1,000 inhabitants-year) adjusted on gender, age and prior underlying chronic disease was 17.9 (95% CI: 16.3–19.6), 20.8 (19.0–22.8), 22.5 (19.0–26.6) and 24.7 (22.7–26.8), respectively. It was 42.1 (38.8–45.8) in elderly people with underlying chronic disease who received both vaccines vs. 58.1 (53.7–62.9) in unvaccinated elderly people. The decrease in mortality rate was 27.0% (20.0–34.0) in subjects who received both vaccines and 16.0% (6.0–24.0) in those who received influenza vaccine. No significant reduction in mortality rate was seen with the pneumococcal vaccine alone. Influenza and/or pneumococcal vaccinations did not decrease antibiotic consumption that drastically increases during the winter period. An additive effect was observed in the prevention of all-cause mortality with influenza and pneumococcal vaccines given together in elderly people, including in those with underlying chronic disease.