Background: Even though the efficacy of pneumococcal vaccine against invasive pneumococcal infections and other closely related infections has been established, its use in the United States is only one quarter of that of influenza vaccine. The simultaneous administration of the two vaccines could be expected to raise the coverage of pneumococcal vaccination to a considerable degree. There is a paucity of data regarding the reactions associated with the simultaneous administration of pneumococcal and influenza vaccines.
Methods: All persons aged 65 years or older living in 29 administrative districts in Northern Finland were offered influenza vaccine alone or influenza and pneumococcal vaccines. A total of 9336 persons (49.6% of the target population) accepted vaccination: 4581 persons born in odd years received influenza vaccine, and 4755 persons born in even years received influenza and pneumococcal vaccines. Local reactions were recorded in a diary by vaccines on the day of vaccination and for 4 days afterward according to the following scale: no reaction, mild reaction, strong reaction, and disabling reaction. The participants who felt feverish were asked to measure and record their temperature. Ninety-three percent of those vaccinated returned the diary.
Results: No serious reactions were observed. The incidence of local reactions was 284 per 1000 vaccinations in the influenza-vaccinated group and 441 per 1000 vaccinations in the influenza-pneumococcal-vaccinated group, a difference of 157 (95% confidence interval, 137 to 176), and that of fever (temperature, at least 37.5 degrees C) was 10 and 24 per 1000, respectively, for a difference of 14 (95% confidence interval, 9 to 19). The frequency of local reactions decreased with advancing age.
Conclusion: Because the adverse reactions to the pneumococcal and influenza vaccines when given together were mild, we conclude that the simultaneous administration of the two vaccines to the elderly population, irrespective of age, is safe.